1
|
Sun Q, Gilgen AK, Wittwer R, von Arx G, van der Heijden MGA, Klaus VH, Buchmann N. Drought effects on trait space of winter wheat are independent of land management. THE NEW PHYTOLOGIST 2024. [PMID: 38785184 DOI: 10.1111/nph.19851] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/04/2023] [Accepted: 05/06/2024] [Indexed: 05/25/2024]
Abstract
Investigating plant responses to climate change is key to develop suitable adaptation strategies. However, whether changes in land management can alleviate increasing drought threats to crops in the future is still unclear. We conducted a management × drought experiment with winter wheat (Triticum aestivum L.) to study plant water and vegetative traits in response to drought and management (conventional vs organic farming, with intensive vs conservation tillage). Water traits (root water uptake pattern, stem metaxylem area, leaf water potential, stomatal conductance) and vegetative traits (plant height, leaf area, leaf Chl content) were considered simultaneously to characterise the variability of multiple traits in a trait space, using principal component analysis. Management could not alleviate the drought impacts on plant water traits as it mainly affected vegetative traits, with yields ultimately being affected by both management and drought. Trait spaces were clearly separated between organic and conventional management as well as between drought and control conditions. Moreover, changes in trait space triggered by management and drought were independent from each other. Neither organic management nor conservation tillage eased drought impacts on winter wheat. Thus, our study raised concerns about the effectiveness of these management options as adaptation strategies to climate change.
Collapse
Affiliation(s)
- Qing Sun
- Institute of Agricultural Sciences, ETH Zurich, 8092, Zurich, Switzerland
- Climate and Environmental Physics, Physics Institute, University of Bern, 3012, Bern, Switzerland
- Oeschger Centre for Climate Change Research, University of Bern, 3012, Bern, Switzerland
| | - Anna K Gilgen
- Institute of Agricultural Sciences, ETH Zurich, 8092, Zurich, Switzerland
| | - Raphaël Wittwer
- Research Division Agroecology and Environment, Plant-Soil-Interactions, Agroscope, Reckenholzstrasse 191, 8046, Zürich, Switzerland
| | - Georg von Arx
- Oeschger Centre for Climate Change Research, University of Bern, 3012, Bern, Switzerland
- Swiss Federal Institute for Forest Snow and Landscape Research WSL, 8903, Birmensdorf, Switzerland
| | - Marcel G A van der Heijden
- Research Division Agroecology and Environment, Plant-Soil-Interactions, Agroscope, Reckenholzstrasse 191, 8046, Zürich, Switzerland
- Department of Plant and Microbial Biology, University of Zurich, Zollikersrasse 107, 8008, Zürich, Switzerland
| | - Valentin H Klaus
- Institute of Agricultural Sciences, ETH Zurich, 8092, Zurich, Switzerland
- Research Division Animal Production Systems and Animal Health, Forage Production and Grassland Systems, Agroscope, Reckenholzstrasse 191, 8046, Zurich, Switzerland
| | - Nina Buchmann
- Institute of Agricultural Sciences, ETH Zurich, 8092, Zurich, Switzerland
| |
Collapse
|
2
|
McElwain JC, Matthaeus WJ, Barbosa C, Chondrogiannis C, O' Dea K, Jackson B, Knetge AB, Kwasniewska K, Nair R, White JD, Wilson JP, Montañez IP, Buckley YM, Belcher CM, Nogué S. Functional traits of fossil plants. THE NEW PHYTOLOGIST 2024; 242:392-423. [PMID: 38409806 DOI: 10.1111/nph.19622] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/10/2023] [Accepted: 12/19/2023] [Indexed: 02/28/2024]
Abstract
A minuscule fraction of the Earth's paleobiological diversity is preserved in the geological record as fossils. What plant remnants have withstood taphonomic filtering, fragmentation, and alteration in their journey to become part of the fossil record provide unique information on how plants functioned in paleo-ecosystems through their traits. Plant traits are measurable morphological, anatomical, physiological, biochemical, or phenological characteristics that potentially affect their environment and fitness. Here, we review the rich literature of paleobotany, through the lens of contemporary trait-based ecology, to evaluate which well-established extant plant traits hold the greatest promise for application to fossils. In particular, we focus on fossil plant functional traits, those measurable properties of leaf, stem, reproductive, or whole plant fossils that offer insights into the functioning of the plant when alive. The limitations of a trait-based approach in paleobotany are considerable. However, in our critical assessment of over 30 extant traits we present an initial, semi-quantitative ranking of 26 paleo-functional traits based on taphonomic and methodological criteria on the potential of those traits to impact Earth system processes, and for that impact to be quantifiable. We demonstrate how valuable inferences on paleo-ecosystem processes (pollination biology, herbivory), past nutrient cycles, paleobiogeography, paleo-demography (life history), and Earth system history can be derived through the application of paleo-functional traits to fossil plants.
Collapse
Affiliation(s)
- Jennifer C McElwain
- School of Natural Sciences, Botany, Trinity College Dublin, Dublin, D02 PN40, Ireland
| | - William J Matthaeus
- School of Natural Sciences, Botany, Trinity College Dublin, Dublin, D02 PN40, Ireland
| | - Catarina Barbosa
- School of Natural Sciences, Botany, Trinity College Dublin, Dublin, D02 PN40, Ireland
| | | | - Katie O' Dea
- School of Natural Sciences, Botany, Trinity College Dublin, Dublin, D02 PN40, Ireland
| | - Bea Jackson
- School of Natural Sciences, Botany, Trinity College Dublin, Dublin, D02 PN40, Ireland
| | - Antonietta B Knetge
- School of Natural Sciences, Botany, Trinity College Dublin, Dublin, D02 PN40, Ireland
| | - Kamila Kwasniewska
- School of Natural Sciences, Botany, Trinity College Dublin, Dublin, D02 PN40, Ireland
| | - Richard Nair
- School of Natural Sciences, Botany, Trinity College Dublin, Dublin, D02 PN40, Ireland
| | - Joseph D White
- Department of Biology, Baylor University, Waco, 76798-7388, TX, USA
| | - Jonathan P Wilson
- Department of Environmental Studies, Haverford College, Haverford, Pennsylvania, 19041, PA, USA
| | - Isabel P Montañez
- UC Davis Institute of the Environment, University of California, Davis, CA, 95616, USA
- Department of Earth and Planetary Sciences, University of California, Davis, CA, 95616, USA
| | - Yvonne M Buckley
- School of Natural Sciences, Zoology, Trinity College Dublin, Dublin, D02 PN40, Ireland
| | | | - Sandra Nogué
- Universitat Autònoma de Barcelona, Bellaterra (Cerdanyola del Vallès), 08193, Catalonia, Spain
- CREAF, Bellaterra (Cerdanyola del Vallès), 08193, Catalonia, Spain
| |
Collapse
|
3
|
Khudykh TA, Belokopytova LV, Yang B, Kholdaenko YA, Babushkina EA, Vaganov EA. New Methods in Digital Wood Anatomy: The Use of Pixel-Contrast Densitometry with Example of Angiosperm Shrubs in Southern Siberia. BIOLOGY 2024; 13:223. [PMID: 38666835 PMCID: PMC11048334 DOI: 10.3390/biology13040223] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/07/2024] [Revised: 03/25/2024] [Accepted: 03/27/2024] [Indexed: 04/28/2024]
Abstract
This methodological study describes the adaptation of a new method in digital wood anatomy, pixel-contrast densitometry, for angiosperm species. The new method was tested on eight species of shrubs and small trees in Southern Siberia, whose wood structure varies from ring-porous to diffuse-porous, with different spatial organizations of vessels. A two-step transformation of wood cross-section photographs by smoothing and Otsu's classification algorithm was proposed to separate images into cell wall areas and empty spaces within (lumen) and between cells. Good synchronicity between measurements within the ring allowed us to create profiles of wood porosity (proportion of empty spaces) describing the growth ring structure and capturing inter-annual differences between rings. For longer-lived species, 14-32-year series from at least ten specimens were measured. Their analysis revealed that maximum (for all wood types), mean, and minimum porosity (for diffuse-porous wood) in the ring have common external signals, mostly independent of ring width, i.e., they can be used as ecological indicators. Further research directions include a comparison of this method with other approaches in densitometry, clarification of sample processing, and the extraction of ecologically meaningful data from wood structures.
Collapse
Affiliation(s)
- Timofey A. Khudykh
- Institute of Ecology and Geography, Siberian Federal University, 660041 Krasnoyarsk, Russia; (T.A.K.); (Y.A.K.); (E.A.B.); (E.A.V.)
| | - Liliana V. Belokopytova
- Institute of Ecology and Geography, Siberian Federal University, 660041 Krasnoyarsk, Russia; (T.A.K.); (Y.A.K.); (E.A.B.); (E.A.V.)
- Khakass Technical Institute, Siberian Federal University, 655017 Abakan, Russia
| | - Bao Yang
- School of Geography and Ocean Science, Nanjing University, Nanjing 210023, China;
| | - Yulia A. Kholdaenko
- Institute of Ecology and Geography, Siberian Federal University, 660041 Krasnoyarsk, Russia; (T.A.K.); (Y.A.K.); (E.A.B.); (E.A.V.)
- Khakass Technical Institute, Siberian Federal University, 655017 Abakan, Russia
| | - Elena A. Babushkina
- Institute of Ecology and Geography, Siberian Federal University, 660041 Krasnoyarsk, Russia; (T.A.K.); (Y.A.K.); (E.A.B.); (E.A.V.)
- Khakass Technical Institute, Siberian Federal University, 655017 Abakan, Russia
| | - Eugene A. Vaganov
- Institute of Ecology and Geography, Siberian Federal University, 660041 Krasnoyarsk, Russia; (T.A.K.); (Y.A.K.); (E.A.B.); (E.A.V.)
- Department of Dendroecology, V.N. Sukachev Institute of Forest, Siberian Branch of the Russian Academy of Science, 660036 Krasnoyarsk, Russia
| |
Collapse
|
4
|
Li Y, Xin Z, Yao B, Duan R, Dong X, Bao Y, Li X, Ma Y, Huang Y, Luo F, Li X, Wei X, Jiang ZR, Lozada-Gobilard S, Zhu J. Density affects plant size in the Gobi Desert. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 912:169401. [PMID: 38114032 DOI: 10.1016/j.scitotenv.2023.169401] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/16/2023] [Revised: 12/12/2023] [Accepted: 12/13/2023] [Indexed: 12/21/2023]
Abstract
Plant size is a crucial functional trait with substantial implications in agronomy and forestry. Understanding the factors influencing plant size is essential for ecosystem management and restoration efforts. Various environmental factors and plant density play significant roles in plant size. However, how plant size responds to mean annual precipitation (MAP), mean annual temperature (MAT), and density in the arid areas remains incomplete. To address this knowledge gap, we conducted comprehensive vegetation surveys in the Gobi Desert in northwestern China with a MAP below 250 mm. We also collected climate data to disentangle the respective influences of climate and density on the community-weighted plant height, crown length, and crown width. Our observations revealed that the community-weighted mean plant height, crown length, and width demonstrated a positive association with MAT but negative relationships with both MAP and density. These patterns can be attributed to the predominance of shrubs over herbs in arid regions, as shrubs tend to be larger in size. The proportion of shrubs increases with MAT, while it decreases with MAP and density, resulting in higher plant height and larger crown dimensions. Although both MAP and MAT affect plant size in the Gobi Desert, our findings highlight the stronger role of plant density in regulating plant size, indicating that the surrounding plant community and competition among individuals are crucial drivers of plant size patterns. Our findings provide valuable guidance for nature-based solutions for vegetation restoration and ecosystem management, highlighting the importance of considering plant density as a key factor when designing and implementing restoration strategies in arid areas.
Collapse
Affiliation(s)
- Yonghua Li
- Institute of Ecological Conservation and Restoration, Chinese Academy of Forestry, Beijing 100091, China; Gansu Dunhuang Desert Ecosystem National Observation and Research Station, Dunhuang 736200, China; Kumtag Desert Ecosystem National Observation and Research Station, Dunhuang 736200, China
| | - Zhiming Xin
- Experimental Center of Desert Forestry, Chinese Academy of Forestry, Dengkou County, Inner Mongolia 015200, China; Inner Mongolia Dengkou Desert Ecosystem National Observation Research Station, Dengkou 015200, China
| | - Bin Yao
- Institute of Ecological Conservation and Restoration, Chinese Academy of Forestry, Beijing 100091, China; Gansu Dunhuang Desert Ecosystem National Observation and Research Station, Dunhuang 736200, China; Kumtag Desert Ecosystem National Observation and Research Station, Dunhuang 736200, China
| | - Ruibing Duan
- Experimental Center of Desert Forestry, Chinese Academy of Forestry, Dengkou County, Inner Mongolia 015200, China; Inner Mongolia Dengkou Desert Ecosystem National Observation Research Station, Dengkou 015200, China
| | - Xue Dong
- Experimental Center of Desert Forestry, Chinese Academy of Forestry, Dengkou County, Inner Mongolia 015200, China; Inner Mongolia Dengkou Desert Ecosystem National Observation Research Station, Dengkou 015200, China
| | - Yanfeng Bao
- Institute of Ecological Conservation and Restoration, Chinese Academy of Forestry, Beijing 100091, China; Gansu Dunhuang Desert Ecosystem National Observation and Research Station, Dunhuang 736200, China; Kumtag Desert Ecosystem National Observation and Research Station, Dunhuang 736200, China
| | - Xinle Li
- Experimental Center of Desert Forestry, Chinese Academy of Forestry, Dengkou County, Inner Mongolia 015200, China; Inner Mongolia Dengkou Desert Ecosystem National Observation Research Station, Dengkou 015200, China
| | - Yuan Ma
- Experimental Center of Desert Forestry, Chinese Academy of Forestry, Dengkou County, Inner Mongolia 015200, China; Inner Mongolia Dengkou Desert Ecosystem National Observation Research Station, Dengkou 015200, China
| | - Yaru Huang
- Experimental Center of Desert Forestry, Chinese Academy of Forestry, Dengkou County, Inner Mongolia 015200, China; Inner Mongolia Dengkou Desert Ecosystem National Observation Research Station, Dengkou 015200, China
| | - Fengmin Luo
- Experimental Center of Desert Forestry, Chinese Academy of Forestry, Dengkou County, Inner Mongolia 015200, China; Inner Mongolia Dengkou Desert Ecosystem National Observation Research Station, Dengkou 015200, China
| | - Xing Li
- Experimental Center of Desert Forestry, Chinese Academy of Forestry, Dengkou County, Inner Mongolia 015200, China; Inner Mongolia Dengkou Desert Ecosystem National Observation Research Station, Dengkou 015200, China
| | - Xu Wei
- School of Life Sciences, East China Normal University, Shanghai 200241, China
| | - Zi-Ru Jiang
- Laboratory of Forest Protection, Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya 4648601, Japan
| | | | - Jinlei Zhu
- Institute of Ecological Conservation and Restoration, Chinese Academy of Forestry, Beijing 100091, China; Gansu Dunhuang Desert Ecosystem National Observation and Research Station, Dunhuang 736200, China; Kumtag Desert Ecosystem National Observation and Research Station, Dunhuang 736200, China.
| |
Collapse
|
5
|
Herrera JC, Savoi S, Dostal J, Elezovic K, Chatzisavva M, Forneck A, Savi T. The legacy of past droughts induces water-sparingly behaviour in Grüner Veltliner grapevines. PLANT BIOLOGY (STUTTGART, GERMANY) 2024. [PMID: 38315499 DOI: 10.1111/plb.13620] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2023] [Accepted: 01/08/2024] [Indexed: 02/07/2024]
Abstract
Drought is becoming more frequent and severe in numerous wine-growing regions. Nevertheless, limited research has examined the legacy of recurrent droughts, focusing on leaf physiology and anatomy over consecutive seasons. We investigated drought legacies (after 2 years of drought exposure) in potted grapevines, focusing on stomatal behaviour under well-watered conditions during the third year. Vines were subjected for two consecutive years to short- (SD) or long-term (LD) seasonal droughts, or well-watered conditions (WW). In the third year, all plants were grown without water limitation. Water potential and gas exchange were monitored throughout the three seasons, while leaf morpho-anatomical traits were measured at the end of the third year. During droughts (1st and 2nd year), stem water potential of SD and LD plants fell below -1.1 MPa, with a consequent 75% reduction in stomatal conductance (gs ) compared to WW. In the 3rd year, when all vines were daily irrigated to soil capacity (midday stem water potential ~ -0.3 MPa), 45% lower values of gs were observed in the ex-LD group compared to both ex-SD and ex-WW. Reduced midrib vessel diameter, lower leaf theoretical hydraulic conductivity, and smaller stomata were measured in ex-LD leaves compared to ex-SD and ex-WW, likely contributing to the reduced gas exchange. Our findings suggest that grapevines exposed to drought may adopt a more water-conserving strategy in subsequent seasons, irrespective of current soil water availability, with the degree of change influenced by the intensity and duration of past drought events.
Collapse
Affiliation(s)
- J C Herrera
- Department of Crop Sciences, Institute of Viticulture and Pomology, University of Natural Resources and Life Sciences, Vienna, Austria
| | - S Savoi
- Department of Agricultural, Forest and Food Sciences, University of Turin, Grugliasco, Italy
| | - J Dostal
- Department of Crop Sciences, Institute of Viticulture and Pomology, University of Natural Resources and Life Sciences, Vienna, Austria
| | - K Elezovic
- Department of Crop Sciences, Institute of Viticulture and Pomology, University of Natural Resources and Life Sciences, Vienna, Austria
| | - M Chatzisavva
- Department of Crop Sciences, Institute of Viticulture and Pomology, University of Natural Resources and Life Sciences, Vienna, Austria
| | - A Forneck
- Department of Crop Sciences, Institute of Viticulture and Pomology, University of Natural Resources and Life Sciences, Vienna, Austria
| | - T Savi
- Department of Integrative Biology and Biodiversity Research, Institute of Botany, University of Natural Resources and Life Sciences, Vienna, Austria
| |
Collapse
|
6
|
Ocheltree TW, Gleason SM. Grass veins are leaky pipes: vessel widening in grass leaves explain variation in stomatal conductance and vessel diameter among species. THE NEW PHYTOLOGIST 2024; 241:243-252. [PMID: 37964665 DOI: 10.1111/nph.19368] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/2023] [Accepted: 09/26/2023] [Indexed: 11/16/2023]
Abstract
The widening of xylem vessels from tip to base of trees is an adaptation to minimize the hydraulic resistance of a long pathway. Given that parallel veins of monocot leaves do not branch hierarchically, vessels should also widen basipetally but, in addition to minimizing resistance, should also account for water volume lost to transpiration since they supply water to the lamina along their lengths, that is 'leakiness'. We measured photosynthesis, stomatal conductance, and vessel diameter at five locations along each leaf of five perennial grass species. We found that the rate of conduit widening in grass leaves was larger than the widening exponent required to minimize pathlength resistance (0.35 vs c. 0.22). Furthermore, variation in the widening exponent among species was positively correlated with maximal stomatal conductance (r2 = 0.20) and net CO2 assimilation (r2 = 0.45). These results suggest that faster rates of conduit widening (> 0.22) were associated with higher rates of water loss. Taken together, our results show that the widening exponent is linked to plant function in grass leaves and that natural selection has favored parallel vein networks that are constructed to meet transpiration requirements while minimizing hydraulic resistance within grass blades.
Collapse
Affiliation(s)
- Troy W Ocheltree
- Department of Forest and Rangeland Stewardship, Colorado State University, Fort Collins, CO, 80523, USA
| | - Sean M Gleason
- Water Management and Systems Research Unit, United States Department of Agriculture, Agricultural Research Service, Fort Collins, CO, 80526, USA
| |
Collapse
|
7
|
Segovia-Rivas A, Olson ME. Temperature and Turgor "Limitation" and Environmental "Control" in Xylem Biology and Dendrochronology. Integr Comp Biol 2023; 63:1364-1375. [PMID: 37550219 DOI: 10.1093/icb/icad110] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2023] [Revised: 07/23/2023] [Accepted: 07/28/2023] [Indexed: 08/09/2023] Open
Abstract
Trees and other woody plants are immensely ecologically important, making it essential to understand the causes of relationships between tree structure and function. To help these efforts, we highlight persistent traditions in plant biology of appealing to environmental factors "limiting" or "controlling" woody plant features. Examples include the idea that inevitable drops in cell turgor with plant height limit cell expansion and thus leaf size and tree height; that low temperatures prohibit lignification of cells and thus the growth of woody plants at high elevation; and notions from dendrochronology and related fields that climate factors such as rainfall and temperature "control" growth ring features. We show that notions of "control," "limitation," and the like imply that selection would favor a given trait value, but that these would-be favored values are developmentally impossible to produce. Such "limitation" scenarios predict trait frequency distributions that are very narrow and are abruptly curtailed at the upper limit of developmental possibility (the right-hand side of the distribution). Such distributions have, to our knowledge, never been observed, so we see little empirical support for "limitation" hypotheses. We suggest that, as a more productive starting point, plant biologists should examine adaptation hypotheses, in which developmental possibility is wide (congruent with the wide ranges of trait variation that really are observed), but only some of the possible variants are favored. We suggest that (1) the traditional the proximate/ultimate causation distinction, (2) purging scenarios of teleology/anthropomorphism, and (3) stating hypotheses in terms of developmental potential and natural selection are three simple ways of making "limitation" hypotheses clearer with regard to biological process and thus empirically testable.
Collapse
Affiliation(s)
- Alí Segovia-Rivas
- Instituto de Biología, , Universidad Nacional Autónoma de México, Tercer Circuito sn de Ciudad Universitaria, Ciudad de México 04510, Mexico
| | - Mark E Olson
- Instituto de Biología, , Universidad Nacional Autónoma de México, Tercer Circuito sn de Ciudad Universitaria, Ciudad de México 04510, Mexico
| |
Collapse
|
8
|
Wu A, Anderegg LDL, Dawson TE, Trugman AT. Leaf trait coordination and variation of blue oak across topo-environmental scales. TREE PHYSIOLOGY 2023; 43:2098-2108. [PMID: 37847600 DOI: 10.1093/treephys/tpad127] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/23/2023] [Accepted: 09/27/2023] [Indexed: 10/19/2023]
Abstract
Trees are arguably the most diverse and complex macro-organisms on Earth. The equally diverse functions of trees directly impact fluxes of carbon, water and energy from the land surface. A number of recent studies have shed light on the substantial within-species variability across plant traits, including aspects of leaf morphology and plant allocation of photosynthates to leaf biomass. Yet, within-tree variability in leaf traits due to microclimatic variations, leaf hydraulic coordination across traits at different physiological scales and variations in leaf traits over a growing season remain poorly studied. This knowledge gap is stymieing the fundamental understanding of what drives trait variation and covariation from tissues to trees to landscapes. Here, we present an extensive dataset measuring within-tree heterogeneity in leaf traits in California's blue oak (Quercus douglasii) across an edaphic gradient and over the course of a growing season at an oak-grass savanna in Southern CA, USA. We found a high level of within-tree crown leaf area:sapwood area variation that was not attributable to sample height or aspect. We also found a higher level of trait integration at the tree level, rather than branch level, suggesting that trees optimize water use at the organismal level. Despite the large variance in traits within a tree crown and across trees, we did not find strong evidence for adaptive plasticity or acclimation in leaf morphological traits (e.g., changes to phenotype which increased fitness) across temporal and spatial water availability gradients. Collectively, our results highlight strong variation in drought-related physiology, but limited evidence for adaptive trait plasticity over shorter time scales.
Collapse
Affiliation(s)
- Angelica Wu
- Department of Integrative Biology, 3040 Valley Life Sciences Building, University of California, Berkeley, CA 94720, USA
| | - Leander D L Anderegg
- Department of Ecology, Evolution, and Marine Biology, Noble Hall, University of California, Santa Barbara, CA 93106, USA
| | - Todd E Dawson
- Department of Integrative Biology, 3040 Valley Life Sciences Building, University of California, Berkeley, CA 94720, USA
| | - Anna T Trugman
- Department of Geography, Ellison Hall, University of California, Santa Barbara, CA 93106, USA
| |
Collapse
|
9
|
Petrone-Mendoza E, Vergara-Silva F, Olson ME. Plant morpho evo-devo. TRENDS IN PLANT SCIENCE 2023; 28:1257-1276. [PMID: 37423784 DOI: 10.1016/j.tplants.2023.06.007] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/04/2022] [Revised: 06/02/2023] [Accepted: 06/07/2023] [Indexed: 07/11/2023]
Abstract
Evo-devo is often thought of as being the study of which genes underlie which phenotypes. However, evo-devo is much more than this, especially in plant science. In leaf scars along stems, cell changes across wood growth rings, or flowers along inflorescences, plants trace a record of their own development. Plant morpho evo-devo provides data that genes could never furnish on themes such as heterochrony, the evolution of temporal phenotypes, modularity, and phenotype-first evolution. As plant science surges into increasingly -omic realms, it is essential to keep plant morpho evo-devo in full view as an honored member of the evo-devo canon, ensuring that plant scientists can, wherever they are, generate fundamental insights at the appropriate level of biological organization.
Collapse
Affiliation(s)
- Emilio Petrone-Mendoza
- Instituto de Biología, Universidad Nacional Autónoma de México, Tercer Circuito s/n de Ciudad Universitaria, Ciudad de México 04510, México; Posgrado en Ciencias Biológicas, Unidad de Posgrado, Edificio D, 1° Piso, Circuito de Posgrados, Ciudad Universitaria, Coyoacán, C.P. 04510, CDMX, México
| | - Francisco Vergara-Silva
- Laboratorio de Teoría Evolutiva e Historia de la Ciencia, Jardín Botánico, Instituto de Biología, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Mark E Olson
- Instituto de Biología, Universidad Nacional Autónoma de México, Tercer Circuito s/n de Ciudad Universitaria, Ciudad de México 04510, México.
| |
Collapse
|
10
|
Martínez-Vilalta J, García-Valdés R, Jump A, Vilà-Cabrera A, Mencuccini M. Accounting for trait variability and coordination in predictions of drought-induced range shifts in woody plants. THE NEW PHYTOLOGIST 2023; 240:23-40. [PMID: 37501525 DOI: 10.1111/nph.19138] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/03/2023] [Accepted: 06/20/2023] [Indexed: 07/29/2023]
Abstract
Functional traits offer a promising avenue to improve predictions of species range shifts under climate change, which will entail warmer and often drier conditions. Although the conceptual foundation linking traits with plant performance and range shifts appears solid, the predictive ability of individual traits remains generally low. In this review, we address this apparent paradox, emphasizing examples of woody plants and traits associated with drought responses at the species' rear edge. Low predictive ability reflects the fact not only that range dynamics tend to be complex and multifactorial, as well as uncertainty in the identification of relevant traits and limited data availability, but also that trait effects are scale- and context-dependent. The latter results from the complex interactions among traits (e.g. compensatory effects) and between them and the environment (e.g. exposure), which ultimately determine persistence and colonization capacity. To confront this complexity, a more balanced coverage of the main functional dimensions involved (stress tolerance, resource use, regeneration and dispersal) is needed, and modelling approaches must be developed that explicitly account for: trait coordination in a hierarchical context; trait variability in space and time and its relationship with exposure; and the effect of biotic interactions in an ecological community context.
Collapse
Affiliation(s)
- Jordi Martínez-Vilalta
- CREAF, E08193, Bellaterra (Cerdanyola del Vallès), Catalonia, Spain
- Universitat Autònoma de Barcelona, E08193, Bellaterra (Cerdanyola del Vallès), Catalonia, Spain
| | - Raúl García-Valdés
- CREAF, E08193, Bellaterra (Cerdanyola del Vallès), Catalonia, Spain
- Forest Science and Technology Centre of Catalonia (CTFC), E25280, Solsona, Spain
- Department of Biology, Geology, Physics and Inorganic Chemistry, School of Experimental Sciences and Technology, Rey Juan Carlos University, E28933, Móstoles, Madrid, Spain
| | - Alistair Jump
- Biological and Environmental Sciences, University of Stirling, FK9 4LA, Stirling, UK
| | - Albert Vilà-Cabrera
- CREAF, E08193, Bellaterra (Cerdanyola del Vallès), Catalonia, Spain
- Biological and Environmental Sciences, University of Stirling, FK9 4LA, Stirling, UK
| | - Maurizio Mencuccini
- CREAF, E08193, Bellaterra (Cerdanyola del Vallès), Catalonia, Spain
- ICREA, Pg. Lluís Companys 23, E08010, Barcelona, Spain
| |
Collapse
|
11
|
Sopp SBD, Valbuena R. Vascular optimality dictates plant morphology away from Leonardo's rule. Proc Natl Acad Sci U S A 2023; 120:e2215047120. [PMID: 37722036 PMCID: PMC10523467 DOI: 10.1073/pnas.2215047120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2022] [Accepted: 06/07/2023] [Indexed: 09/20/2023] Open
Abstract
Metabolic scaling theory (MST) provides an understanding of scaling in organismal morphology. Empirical data on the apparently universal pattern of tip-to-base conduit widening across vascular plants motivate a set of generalized MST (gMST) relationships allowing for variable rates of conduit coalescence and taper and a transition between transport and diffusive domains. Our model, with coalescence limited to the distalmost part of the conductive system, reconciles previous MST-based models and extends their applicability to the entire plant. We derive an inverse relationship between stem volume taper and conduit widening, which implies that plant morphology is dictated by vascular optimality and not the assumption of constant sapwood area across all branching levels, contradicting Leonardo's rule. Thus, energy efficiency controls conduit coalescence rate, lowering the carbon cost needed to sustain the vascular network. Our model shows that as a plant grows taller, it must increase conduit widening and coalescence, which may make it more vulnerable to drought. We calculated how our gMST model implies a lower carbon cost to sustain a similar network compared to previous MST-based models. We also show that gMST predicts the cross-sectional area of vessels and their frequency along the relative length better than previous MST models for a range of plant types. We encourage further research obtaining data that would allow testing other gMST predictions that remain unconfirmed empirically, such as conduit coalescence rate in stems. The premise of energy efficiency can potentially become instrumental to our understanding of plant carbon allocation.
Collapse
Affiliation(s)
- S. B. D. Sopp
- School of Natural Sciences, Bangor University, BangorLL57 2UW, United Kingdom
| | - R. Valbuena
- School of Natural Sciences, Bangor University, BangorLL57 2UW, United Kingdom
- Division of Remote Sensing of Forests, Swedish University of Agricultural Sciences, UmeåSE-901 83, Sweden
| |
Collapse
|
12
|
Petit G, Mencuccini M, Carrer M, Prendin AL, Hölttä T. Axial conduit widening, tree height, and height growth rate set the hydraulic transition of sapwood into heartwood. JOURNAL OF EXPERIMENTAL BOTANY 2023; 74:5072-5087. [PMID: 37352139 DOI: 10.1093/jxb/erad227] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Accepted: 06/12/2023] [Indexed: 06/25/2023]
Abstract
The size-related xylem adjustments required to maintain a constant leaf-specific sapwood conductance (KLEAF) with increasing height (H) are still under discussion. Alternative hypotheses are that: (i) the conduit hydraulic diameter (Dh) at any position in the stem and/or (ii) the number of sapwood rings at stem base (NSWr) increase with H. In addition, (iii) reduced stem elongation (ΔH) increases the tip-to-base conductance through inner xylem rings, thus possibly the NSWr contributing to KLEAF. A detailed stem analysis showed that Dh increased with the distance from the ring apex (DCA) in all rings of a Picea abies and a Fagus sylvatica tree. Net of DCA effect, Dh did not increase with H. Using sapwood traits from a global dataset, NSWr increased with H, decreased with ΔH, and the mean sapwood ring width (SWrw) increased with ΔH. A numerical model based on anatomical patterns predicted the effects of H and ΔH on the conductance of inner xylem rings. Our results suggest that the sapwood/heartwood transition depends on both H and ΔH, and is set when the carbon allocation to maintenance respiration of living cells in inner sapwood rings produces a lower gain in total conductance than investing the same carbon in new vascular conduits.
Collapse
Affiliation(s)
- Giai Petit
- Università degli Studi di Padova, Dept. TeSAF, Viale dell'Università 16, 35020 Legnaro (PD), Italy
| | - Maurizio Mencuccini
- CREAF, Bellaterra (Cerdanyola del Vallès), E08193, Spain
- ICREA, Pg. Lluís Companys 23, Barcelona, 08010, Spain
| | - Marco Carrer
- Università degli Studi di Padova, Dept. TeSAF, Viale dell'Università 16, 35020 Legnaro (PD), Italy
| | - Angela Luisa Prendin
- Università degli Studi di Padova, Dept. TeSAF, Viale dell'Università 16, 35020 Legnaro (PD), Italy
- Department of Biology, Ecoinformatics and Biodiversity, Aarhus University, Ny Munkegade 114-116, building 1540, 8000 Aarhus C, Denmark University of Aarhus, Denmark
| | - Teemu Hölttä
- Institute for Atmospheric and Earth System Research/ Forest Sciences, Faculty of Agriculture and Forestry, University of Helsinki, Latokartanonkaari 7, FI 00014 Helsinki, Finland
| |
Collapse
|
13
|
Fickle JC, Pratt RB, Jacobsen AL. Xylem structure and hydraulic function in roots and stems of chaparral shrub species from high and low elevation in the Sierra Nevada, California. PHYSIOLOGIA PLANTARUM 2023; 175:e13970. [PMID: 37401910 DOI: 10.1111/ppl.13970] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/14/2023] [Revised: 06/16/2023] [Accepted: 06/25/2023] [Indexed: 07/05/2023]
Abstract
Xylem structure and hydraulics were compared between individuals at lower and upper elevation distribution limits for five chaparral shrub species along a steep transect in the southern Sierra Nevada, California, USA. Higher-elevation plants experienced frequent winter freeze-thaw events and increased precipitation. We hypothesized that environmental differences would lead to xylem trait differences between high and low elevations, but predictions were complicated because both water stress (low elevation) and freeze-thaw events (high elevation) may select for similar traits, such as narrow vessel diameter. We found significant changes in the ratio of stem xylem area to leaf area (Huber value) between elevations, with more xylem area required to support leaves at low elevations. Co-occurring species significantly differed in their xylem traits, suggesting diverse strategies to cope with the highly seasonal environment of this Mediterranean-type climate region. Roots were more hydraulically efficient and more vulnerable to embolism relative to stems, potentially due to roots being buffered from freeze-thaw stress, which allows them to maintain wider diameter vessels. Knowledge of the structure and function of both roots and stems is likely important in understanding whole-plant response to environmental gradients.
Collapse
Affiliation(s)
- Jaycie C Fickle
- Department of Biology, California State University, Bakersfield, California, USA
- University of Utah, Salt Lake City, Utah, USA
| | - R Brandon Pratt
- Department of Biology, California State University, Bakersfield, California, USA
| | - Anna L Jacobsen
- Department of Biology, California State University, Bakersfield, California, USA
| |
Collapse
|
14
|
Schönauer M, Hietz P, Schuldt B, Rewald B. Root and branch hydraulic functioning and trait coordination across organs in drought-deciduous and evergreen tree species of a subtropical highland forest. FRONTIERS IN PLANT SCIENCE 2023; 14:1127292. [PMID: 37377798 PMCID: PMC10291250 DOI: 10.3389/fpls.2023.1127292] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/19/2022] [Accepted: 04/26/2023] [Indexed: 06/29/2023]
Abstract
Vessel traits are key in understanding trees' hydraulic efficiency, and related characteristics like growth performance and drought tolerance. While most plant hydraulic studies have focused on aboveground organs, our understanding of root hydraulic functioning and trait coordination across organs remains limited. Furthermore, studies from seasonally dry (sub-)tropical ecosystems and mountain forests are virtually lacking and uncertainties remain regarding potentially different hydraulic strategies of plants differing in leaf habit. Here, we compared wood anatomical traits and specific hydraulic conductivities between coarse roots and small branches of five drought-deciduous and eight evergreen angiosperm tree species in a seasonally dry subtropical Afromontane forest in Ethiopia. We hypothesized that largest vessels and highest hydraulic conductivities are found in roots, with greater vessel tapering between roots and equally-sized branches in evergreen angiosperms due to their drought-tolerating strategy. We further hypothesized that the hydraulic efficiencies of root and branches cannot be predicted from wood density, but that wood densities across organs are generally related. Root-to-branch ratios of conduit diameters varied between 0.8 and 2.8, indicating considerable differences in tapering from coarse roots to small branches. While deciduous trees showed larger branch xylem vessels compared to evergreen angiosperms, root-to-branch ratios were highly variable within both leaf habit types, and evergreen species did not show a more pronounced degree of tapering. Empirically determined hydraulic conductivity and corresponding root-to-branch ratios were similar between both leaf habit types. Wood density of angiosperm roots was negatively related to hydraulic efficiency and vessel dimensions; weaker relationships were found in branches. Wood density of small branches was neither related to stem nor coarse root wood densities. We conclude that in seasonally dry subtropical forests, similar-sized coarse roots hold larger xylem vessels than small branches, but the degree of tapering from roots to branches is highly variable. Our results indicate that leaf habit does not necessarily influence the relationship between coarse root and branch hydraulic traits. However, larger conduits in branches and a low carbon investment in less dense wood may be a prerequisite for high growth rates of drought-deciduous trees during their shortened growing season. The correlation of stem and root wood densities with root hydraulic traits but not branch wood points toward large trade-offs in branch xylem towards mechanical properties.
Collapse
Affiliation(s)
- Marian Schönauer
- Department of Forest and Soil Sciences, Institute of Forest Ecology, University of Natural Resources and Life Sciences, Vienna, Austria
- Department of Forest Work Science and Engineering, Department of Forest Sciences and Forest Ecology, Georg-August-Universität Göttingen, Göttingen, Germany
| | - Peter Hietz
- Department of Integrative Biology and Biodiversity Research, Institute of Botany, University of Natural Resources and Life Sciences Vienna, Vienna, Austria
| | - Bernhard Schuldt
- Chair of Forest Botany, Institute of Forest Botany and Forest Zoology, Technical University of Dresden, Tharandt, Germany
| | - Boris Rewald
- Department of Forest and Soil Sciences, Institute of Forest Ecology, University of Natural Resources and Life Sciences, Vienna, Austria
| |
Collapse
|
15
|
Power CC, Assmann JJ, Prendin AL, Treier UA, Kerby JT, Normand S. Improving ecological insights from dendroecological studies of Arctic shrub dynamics: Research gaps and potential solutions. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 851:158008. [PMID: 35988628 DOI: 10.1016/j.scitotenv.2022.158008] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/28/2022] [Revised: 08/01/2022] [Accepted: 08/09/2022] [Indexed: 06/15/2023]
Abstract
Rapid climate change has been driving changes in Arctic vegetation in recent decades, with increased shrub dominance in many tundra ecosystems. Dendroecological observations of tundra shrubs can provide insight into current and past growth and recruitment patterns, both key components for understanding and predicting ongoing and future Arctic shrub dynamics. However, generalizing these dynamics is challenging as they are highly scale-dependent and vary among sites, species, and individuals. Here, we provide a perspective on how some of these challenges can be overcome. Based on a targeted literature search of dendrochronological studies from 2005 to 2022, we highlight five research gaps that currently limit dendro-based studies from revealing cross-scale ecological insight into shrub dynamics across the Arctic biome. We further discuss the related research priorities, suggesting that future studies could consider: 1) increasing focus on intra- and interspecific variation, 2) including demographic responses other than radial growth, 3) incorporating drivers, in addition to warming, at different spatial and temporal scales, 4) implementing systematic and unbiased sampling approaches, and 5) investigating the cellular mechanisms behind the observed responses. Focusing on these aspects in dendroecological studies could improve the value of the field for addressing cross-scale and plant community-framed ecological questions. We outline how this could be facilitated through the integration of community-based dendroecology and dendroanatomy with remote sensing approaches. Integrating new technologies and a more multidisciplinary approach in dendroecological research could provide key opportunities to close important knowledge gaps in our understanding of scale-dependencies, as well as intra- and inter-specific variation, in vegetation community dynamics across the Arctic tundra.
Collapse
Affiliation(s)
- Candice C Power
- Ecoinformatics and Biodiversity, Department of Biology, Aarhus University, Ny Munkegade 114-116, DK-8000 Aarhus C, Denmark; Center for Biodiversity Dynamics in a Changing World, Aarhus University, Ny Munkegade 114-116, DK-8000 Aarhus C, Denmark.
| | - Jakob J Assmann
- Ecoinformatics and Biodiversity, Department of Biology, Aarhus University, Ny Munkegade 114-116, DK-8000 Aarhus C, Denmark; Center for Biodiversity Dynamics in a Changing World, Aarhus University, Ny Munkegade 114-116, DK-8000 Aarhus C, Denmark
| | - Angela L Prendin
- Ecoinformatics and Biodiversity, Department of Biology, Aarhus University, Ny Munkegade 114-116, DK-8000 Aarhus C, Denmark; Center for Biodiversity Dynamics in a Changing World, Aarhus University, Ny Munkegade 114-116, DK-8000 Aarhus C, Denmark
| | - Urs A Treier
- Ecoinformatics and Biodiversity, Department of Biology, Aarhus University, Ny Munkegade 114-116, DK-8000 Aarhus C, Denmark; Center for Biodiversity Dynamics in a Changing World, Aarhus University, Ny Munkegade 114-116, DK-8000 Aarhus C, Denmark
| | - Jeffrey T Kerby
- Center for Biodiversity Dynamics in a Changing World, Aarhus University, Ny Munkegade 114-116, DK-8000 Aarhus C, Denmark; Aarhus Institute of Advanced Studies, Aarhus University, Høegh-Guldbergs Gade 6B, DK-8000 Aarhus C, Denmark
| | - Signe Normand
- Ecoinformatics and Biodiversity, Department of Biology, Aarhus University, Ny Munkegade 114-116, DK-8000 Aarhus C, Denmark; Center for Biodiversity Dynamics in a Changing World, Aarhus University, Ny Munkegade 114-116, DK-8000 Aarhus C, Denmark
| |
Collapse
|
16
|
Weithmann G, Paligi SS, Schuldt B, Leuschner C. Branch xylem vascular adjustments in European beech in response to decreasing water availability across a precipitation gradient. TREE PHYSIOLOGY 2022; 42:2224-2238. [PMID: 35861677 DOI: 10.1093/treephys/tpac080] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/11/2021] [Accepted: 07/02/2022] [Indexed: 06/15/2023]
Abstract
Crucial for the climate adaptation of trees is a xylem anatomical structure capable of adjusting to changing water regimes. Although species comparisons across climate zones have demonstrated anatomical change in response to altered water availability and tree height, less is known about the adaptability of tree vascular systems to increasing water deficits at the intraspecific level. Information on the between-population and within-population variability of xylem traits helps assessing a species' ability to cope with climate change. We investigated the variability of wood anatomical and related hydraulic traits in terminal branches of European beech (Fagus sylvatica L.) trees across a precipitation gradient (520-890 mm year-1) and examined the influence of climatic water balance (CWB), soil water capacity (AWC), neighborhood competition (CI), tree height and branch age on these traits. Furthermore, the relationship between xylem anatomical traits and embolism resistance (P50) was tested. Within-population trait variation was larger than between-population variation. Vessel diameter, lumen-to-sapwood area ratio and potential conductivity of terminal branches decreased with decreasing CWB, but these traits were not affected by AWC, whereas vessel density increased with an AWC decrease. In contrast, none of the studied anatomical traits were influenced by variation in tree height (21-34 m) or CI. Branch age was highly variable (2-22 years) despite equal diameter and position in the flow path, suggesting different growth trajectories in the past. Vessel diameter decreased, and vessel density increased, with increasing branch age, reflecting negative annual radial growth trends. Although vessel diameter was not related to P50, vessel grouping index and lumen-to-sapwood area ratio showed a weak, though highly significant, positive relationship to P50. We conclude that the xylem anatomy of terminal tree-top branches in European beech is modified in response to increasing climatic aridity and/or decreasing soil water availability, independent of a tree height effect.
Collapse
Affiliation(s)
- Greta Weithmann
- Plant Ecology, Albrecht von Haller Institute for Plant Sciences, University of Goettingen, Untere Karspüle 2, 37073 Goettingen, Germany
| | - Sharath Shyamappa Paligi
- Plant Ecology, Albrecht von Haller Institute for Plant Sciences, University of Goettingen, Untere Karspüle 2, 37073 Goettingen, Germany
| | - Bernhard Schuldt
- Plant Ecology, Albrecht von Haller Institute for Plant Sciences, University of Goettingen, Untere Karspüle 2, 37073 Goettingen, Germany
- Ecophysiology and Vegetation Ecology, Julius-von-Sachs-Institute of Biological Sciences, University of Würzburg, Julius-von-Sachs-Platz, 97082 Würzburg, Germany
| | - Christoph Leuschner
- Plant Ecology, Albrecht von Haller Institute for Plant Sciences, University of Goettingen, Untere Karspüle 2, 37073 Goettingen, Germany
- Centre for Biodiversity and Sustainable Land Use (CBL), University of Goettingen, 37075 Goettingen, Germany
| |
Collapse
|
17
|
Pritzkow C, Brown MJM, Carins-Murphy MR, Bourbia I, Mitchell PJ, Brodersen C, Choat B, Brodribb TJ. Conduit position and connectivity affect the likelihood of xylem embolism during natural drought in evergreen woodland species. ANNALS OF BOTANY 2022; 130:431-444. [PMID: 35420657 PMCID: PMC9486930 DOI: 10.1093/aob/mcac053] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2021] [Accepted: 04/11/2022] [Indexed: 06/14/2023]
Abstract
BACKGROUND AND AIMS Hydraulic failure is considered a main cause of drought-induced forest mortality. Yet, we have a limited understanding of how the varying intensities and long time scales of natural droughts induce and propagate embolism within the xylem. METHODS X-ray computed tomography (microCT) images were obtained from different aged branch xylem to study the number, size and spatial distribution of in situ embolized conduits among three dominant tree species growing in a woodland community. KEY RESULTS Among the three studied tree species, those with a higher xylem vulnerability to embolism (higher water potential at 50 % loss of hydraulic conductance; P50) were more embolized than species with lower P50. Within individual stems, the probability of embolism was independent of conduit diameter but associated with conduit position. Rather than the occurrence of random or radial embolism, we observed circumferential clustering of high and low embolism density, suggesting that embolism spreads preferentially among conduits of the same age. Older xylem also appeared more likely to accumulate embolisms than young xylem, but there was no pattern suggesting that branch tips were more vulnerable to cavitation than basal regions. CONCLUSIONS The spatial analysis of embolism occurrence in field-grown trees suggests that embolism under natural drought probably propagates by air spreading from embolized into neighbouring conduits in a circumferential pattern. This pattern offers the possibility to understand the temporal aspects of embolism occurrence by examining stem cross-sections.
Collapse
Affiliation(s)
- Carola Pritzkow
- School of Biology, University of Tasmania, Hobart, TAS, 7005, Australia
| | - Matilda J M Brown
- School of Biology, University of Tasmania, Hobart, TAS, 7005, Australia
| | | | - Ibrahim Bourbia
- School of Biology, University of Tasmania, Hobart, TAS, 7005, Australia
| | | | - Craig Brodersen
- School of the Environment, Yale University, New Haven, CT 06511, USA
| | - Brendan Choat
- Hawkesbury Institute for the Environment, Western Sydney University, Penrith, NSW 2750, Australia
| | | |
Collapse
|
18
|
Wang L, Dai Y, Zhang J, Meng P, Wan X. Xylem structure and hydraulic characteristics of deep roots, shallow roots and branches of walnut under seasonal drought. BMC PLANT BIOLOGY 2022; 22:440. [PMID: 36104814 PMCID: PMC9472371 DOI: 10.1186/s12870-022-03815-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/14/2021] [Accepted: 08/24/2022] [Indexed: 06/15/2023]
Abstract
BACKGROUND Despite the importance of root hydraulics, there is little research on the in situ dynamic responses of embolism formation and embolism repair of roots distributed in different soil depths in response to different water regimes. RESULTS The vessel diameter, hydraulic conductivity, and vulnerability to cavitation were in the order of deep root > shallow root > branch. The midday PLC of shallow root was the highest in the dry season, while the midday PLC of deep root slightly higher than that of branch with no significant difference in the two seasons. The capacity of embolism repair of roots was significantly greater than that of branch both in dry season and wet season. The xylem pressure was in the order of deep roots > shallow root > branch, and it was negative in most of the time for the latter two in the dry season, but positive for both of the roots during the observation period in the wet season. The NSC and starch content in roots were significantly higher than those in branches, especially in the dry season. In contrast, roots had lower content of soluble sugar. CONCLUSIONS The relatively stable water condition in soil, especially in the deep layers, is favorable for the development of larger-diameter vessels in root xylem, however it cannot prevent the root from forming embolism. The mechanism of embolism repair may be different in different parts of plants. Deep roots mainly depend on root pressure to refill the embolized vessels, while branches mainly depend on starch hydrolysis to soluble sugars to do the work, with shallow roots shifted between the two mechanisms in different moisture regimes. There is theoretically an obvious trade-off between conducting efficiency and safety over deep roots, shallow roots and branches. But in natural conditions, roots do not necessarily suffer more severe embolism than branches, maybe due to their root pressure-driven embolism repair and relatively good water conditions.
Collapse
Affiliation(s)
- Lin Wang
- College of Forestry, Shanxi Agricultural University, Taigu, Shanxi, 030801, People's Republic of China
- Institute of New Forestry Technology, Chinese Academy of Forestry, Beijing, 100091, People's Republic of China
| | - Yongxin Dai
- College of Forestry, Shanxi Agricultural University, Taigu, Shanxi, 030801, People's Republic of China
- Institute of New Forestry Technology, Chinese Academy of Forestry, Beijing, 100091, People's Republic of China
| | - Jinsong Zhang
- Research Institute of Forestry, Chinese Academy of Forestry, Beijing, 100091, People's Republic of China
| | - Ping Meng
- Research Institute of Forestry, Chinese Academy of Forestry, Beijing, 100091, People's Republic of China
| | - Xianchong Wan
- Institute of New Forestry Technology, Chinese Academy of Forestry, Beijing, 100091, People's Republic of China.
| |
Collapse
|
19
|
Bittencourt PRDL, Bartholomew DC, Banin LF, Bin Suis MAF, Nilus R, Burslem DFRP, Rowland L. Divergence of hydraulic traits among tropical forest trees across topographic and vertical environment gradients in Borneo. THE NEW PHYTOLOGIST 2022; 235:2183-2198. [PMID: 35633119 PMCID: PMC9545514 DOI: 10.1111/nph.18280] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2022] [Accepted: 05/23/2022] [Indexed: 06/13/2023]
Abstract
Fine-scale topographic-edaphic gradients are common in tropical forests and drive species spatial turnover and marked changes in forest structure and function. We evaluate how hydraulic traits of tropical tree species relate to vertical and horizontal spatial niche specialization along such a gradient. Along a topographic-edaphic gradient with uniform climate in Borneo, we measured six key hydraulic traits in 156 individuals of differing heights in 13 species of Dipterocarpaceae. We investigated how hydraulic traits relate to habitat, tree height and their interaction on this gradient. Embolism resistance increased in trees on sandy soils but did not vary with tree height. By contrast, water transport capacity increased on sandier soils and with increasing tree height. Habitat and height only interact for hydraulic efficiency, with slope for height changing from positive to negative from the clay-rich to the sandier soil. Habitat type influenced trait-trait relationships for all traits except wood density. Our data reveal that variation in the hydraulic traits of dipterocarps is driven by a combination of topographic-edaphic conditions, tree height and taxonomic identity. Our work indicates that hydraulic traits play a significant role in shaping forest structure across topographic-edaphic and vertical gradients and may contribute to niche specialization among dipterocarp species.
Collapse
Affiliation(s)
| | - David C. Bartholomew
- College of Life and Environmental SciencesUniversity of ExeterExeterEX4 4QEUK
- Department of Ecology and Environmental ScienceUmeå University90736UmeåSweden
| | | | | | - Reuben Nilus
- Sabah Forestry DepartmentForest Research CentrePO Box 1407Sandakan90715SabahMalaysia
| | | | - Lucy Rowland
- College of Life and Environmental SciencesUniversity of ExeterExeterEX4 4QEUK
| |
Collapse
|
20
|
Azuma WA, Kawai K, Tanabe T, Nakahata R, Hiura T. Intraspecific variation in growth‐related traits—from leaf to whole‐tree—in three provenances of
Cryptomeria japonica
canopy trees grown in a common garden. Ecol Res 2022. [DOI: 10.1111/1440-1703.12349] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Wakana A. Azuma
- Graduate School of Agricultural Science Kobe University Kobe Japan
- Graduate School of Agriculture Kyoto University Kyoto Japan
| | - Kiyosada Kawai
- Center for Ecological Research Kyoto University Otsu Japan
- Forestry Division Japan International Research Center for Agricultural Sciences (JIRCAS) Tsukuba Japan
| | - Tomoko Tanabe
- Graduate School of Global Environmental Studies Kyoto University Kyoto Japan
| | - Ryo Nakahata
- Graduate School of Agriculture Kyoto University Kyoto Japan
- Graduate School of Agricultural and Life Sciences The University of Tokyo Tokyo Japan
| | - Tsutom Hiura
- Department of Ecosystem Studies The University of Tokyo Tokyo Japan
| |
Collapse
|
21
|
Johnson DM, Katul G, Domec J. Catastrophic hydraulic failure and tipping points in plants. PLANT, CELL & ENVIRONMENT 2022; 45:2231-2266. [PMID: 35394656 PMCID: PMC9544843 DOI: 10.1111/pce.14327] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2021] [Revised: 03/14/2022] [Accepted: 03/20/2022] [Indexed: 06/12/2023]
Abstract
Water inside plants forms a continuous chain from water in soils to the water evaporating from leaf surfaces. Failures in this chain result in reduced transpiration and photosynthesis and are caused by soil drying and/or cavitation-induced xylem embolism. Xylem embolism and plant hydraulic failure share several analogies to 'catastrophe theory' in dynamical systems. These catastrophes are often represented in the physiological and ecological literature as tipping points when control variables exogenous (e.g., soil water potential) or endogenous (e.g., leaf water potential) to the plant are allowed to vary on time scales much longer than time scales associated with cavitation events. Here, plant hydraulics viewed from the perspective of catastrophes at multiple spatial scales is considered with attention to bubble expansion within a xylem conduit, organ-scale vulnerability to embolism, and whole-plant biomass as a proxy for transpiration and hydraulic function. The hydraulic safety-efficiency tradeoff, hydraulic segmentation and maximum plant transpiration are examined using this framework. Underlying mechanisms for hydraulic failure at fine scales such as pit membranes and cell-wall mechanics, intermediate scales such as xylem network properties and at larger scales such as soil-tree hydraulic pathways are discussed. Understudied areas in plant hydraulics are also flagged where progress is urgently needed.
Collapse
Affiliation(s)
- Daniel M. Johnson
- Warnell School of Forestry and Natural ResourcesUniversity of GeorgiaAthensGeorgiaUSA
| | - Gabriel Katul
- Department of Civil and Environmental EngineeringDuke UniversityDurhamNorth CarolinaUSA
- Nicholas School of the EnvironmentDuke UniversityDurhamNorth CarolinaUSA
| | - Jean‐Christophe Domec
- Nicholas School of the EnvironmentDuke UniversityDurhamNorth CarolinaUSA
- Department of ForestryBordeaux Sciences Agro, UMR INRAE‐ISPA 1391GradignanFrance
| |
Collapse
|
22
|
Savage JA, Kiecker T, McMann N, Park D, Rothendler M, Mosher K. Leaf out time correlates with wood anatomy across large geographic scales and within local communities. THE NEW PHYTOLOGIST 2022; 235:953-964. [PMID: 35179794 PMCID: PMC9313884 DOI: 10.1111/nph.18041] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Accepted: 01/24/2022] [Indexed: 06/14/2023]
Abstract
There is a long-standing idea that the timing of leaf production in seasonally cold climates is linked to xylem anatomy, specifically vessel diameter because of the hydraulic requirements of expanding leaves. We tested for a relationship between the timing of leaf out and vessel diameter in 220 plants in three common gardens accounting for species' phylogenetic relationships. We investigated how vessel diameter related to wood porosity, plant height and leaf length. We also used dye perfusion tests to determine whether plants relied on xylem produced during the previous growing season at the time of leaf out. In all three gardens, there was later leaf out in species with wider vessels. Ring-porous species had the widest vessels, exhibited latest leaf out and relied less on xylem made during the previous growing season than diffuse-porous species. Wood anatomy and leaf phenology did not exhibit a phylogenetic signal. The timing of leaf out is correlated with wood anatomy across species regardless of species' geographic origin and phylogenetic relationships. This correlation could be a result of developmental and physiological links between leaves and wood or tied to a larger safety efficiency trade-off.
Collapse
Affiliation(s)
| | - Thomas Kiecker
- Department of BiologyUniversity of MinnesotaDuluthMN55812USA
| | - Natalie McMann
- Department of BiologyUniversity of MinnesotaDuluthMN55812USA
| | - Daniel Park
- Department of Biological SciencesPurdue UniversityWest LafayetteIN47907USA
| | | | - Kennedy Mosher
- Department of BiologyUniversity of MinnesotaDuluthMN55812USA
| |
Collapse
|
23
|
Tree height effects on vascular anatomy of upper-canopy twigs across a wide range of tropical rainforest species. JOURNAL OF TROPICAL ECOLOGY 2022. [DOI: 10.1017/s0266467422000335] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Abstract
Vessel diameter variation along the hydraulic pathway determines how much water can be moved against the force of gravity from roots to leaves. While it is well-documented that tree size scales with vessel diameter variation at the stem base due to the effect of basipetal vessel widening, much less is known whether this likewise applies to terminal sun-exposed twigs. To analyze the effect of tree height on twig xylem anatomy, we compiled data for 279 tropical rainforest tree species belonging to 56 families in the lowlands of Jambi Province, Indonesia. Terminal upper-canopy twigs of fully grown individuals were collected and used for wood anatomical analysis.
We show that hydraulically weighted vessel diameter (Dh) and potential hydraulic conductivity (Kp) of upper canopy twigs increase with tree height across species although the relationship was weak. When averaged across given tree height classes irrespectively of species identity, however, a strong dependency of tree height on Dh and Kp was observed, but not on the lumen-to-sapwood area ratio (Al:Ax) or vessel density (VD).
According to the comparison between actual tree height and the maximum tree height reported for a given species in the stand, we show that the vascular xylem anatomy of their terminal twigs reflects their canopy position and thus ecological niche (understory versus overstory) at maturity. We conclude that the capacity to move large quantities of water during the diurnal peak in evaporative demand is a prerequisite for growing tall in a humid tropical environment.
Collapse
|
24
|
Wood Anatomical Traits Respond to Climate but More Individualistically as Compared to Radial Growth: Analyze Trees, Not Means. FORESTS 2022. [DOI: 10.3390/f13060956] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Wood encodes environmental information that can be recovered through the study of tree-ring width and wood anatomical variables such as lumen area or cell-wall thickness. Anatomical variables often provide a stronger hydroclimate signal than tree-ring width, but they show a low tree-to-tree coherence. We investigate the sources of variation in tree-ring width, lumen area, and cell-wall thickness in three pine species inhabiting sites with contrasting climate conditions: Pinus lumholtzii in wet-summer northern Mexico, and Pinus halepensis and Pinus sylvestris in dry-summer north-eastern Spain. We quantified the amount of variance of these three variables explained by spring and summer water balance and how it varied among trees. Wood anatomical variables accounted for a larger inter-individual variability than tree-ring width data. Anatomical traits responded to hydroclimate more individualistically than tree-ring width. This individualistic response represents an important issue in long-term studies on wood anatomical characteristics. We emphasized the degree of variation among individuals of the same population, which has far-reaching implications for understanding tree species’ responses to climate change. Dendroclimatic and wood anatomical studies should focus on trees rather than on the mean population series.
Collapse
|
25
|
Echeverría A, Petrone‐Mendoza E, Segovia‐Rivas A, Figueroa‐Abundiz VA, Olson ME. The vessel wall thickness-vessel diameter relationship across woody angiosperms. AMERICAN JOURNAL OF BOTANY 2022; 109:856-873. [PMID: 35435252 PMCID: PMC9328290 DOI: 10.1002/ajb2.1854] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2021] [Revised: 03/30/2022] [Accepted: 03/31/2022] [Indexed: 05/26/2023]
Abstract
PREMISE Comparative anatomy is necessary to identify the extremes of combinations of functionally relevant structural traits, to ensure that physiological data cover xylem anatomical diversity adequately, and thus achieve a global understanding of xylem structure-function relations. A key trait relationship is that between xylem vessel diameter and wall thickness of both the single vessel and the double vessel+adjacent imperforate tracheary element (ITE). METHODS We compiled a comparative data set with 1093 samples, 858 species, 350 genera, 86 families, and 33 orders. We used broken linear regression and an algorithm to explore changes in parameter values from linear regressions using subsets of the data set to identify a threshold, at 90-µm vessel diameter, in the wall thickness-diameter relationship. RESULTS Below 90 µm diameter for vessels, virtually any wall thickness could be associated with virtually any diameter. Below this threshold, selection is free to favor a very wide array of combinations, such as very thick walls and narrow vessels in ITE-free herbs, or very thin-walled, wide vessels in evergreen dryland pioneers. Above 90 µm, there was a moderate positive relationship. CONCLUSIONS Our analysis shows that the space of vessel wall thickness-diameter combinations is very wide, with selection apparently eliminating individuals with vessel walls "too thin" for their diameter. Most importantly, our survey revealed poorly studied plant hydraulic syndromes (functionally significant trait combinations). These data suggest that the full span of trait combinations, and thus the minimal set of hydraulic syndromes requiring study to span woody plant functional diversity adequately, remains to be documented.
Collapse
Affiliation(s)
- Alberto Echeverría
- Instituto de Biología, Universidad Nacional Autónoma de México, Tercer Circuito s/n de Ciudad Universitaria, Ciudad de México, 04510México
| | - Emilio Petrone‐Mendoza
- Instituto de Biología, Universidad Nacional Autónoma de México, Tercer Circuito s/n de Ciudad Universitaria, Ciudad de México, 04510México
| | - Alí Segovia‐Rivas
- Instituto de Biología, Universidad Nacional Autónoma de México, Tercer Circuito s/n de Ciudad Universitaria, Ciudad de México, 04510México
| | - Víctor A. Figueroa‐Abundiz
- Instituto de Biología, Universidad Nacional Autónoma de México, Tercer Circuito s/n de Ciudad Universitaria, Ciudad de México, 04510México
| | - Mark E. Olson
- Instituto de Biología, Universidad Nacional Autónoma de México, Tercer Circuito s/n de Ciudad Universitaria, Ciudad de México, 04510México
| |
Collapse
|
26
|
Fajardo A, Piper FI, García‐Cervigón AI. The intraspecific relationship between wood density, vessel diameter and other traits across environmental gradients. Funct Ecol 2022. [DOI: 10.1111/1365-2435.14069] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Affiliation(s)
- Alex Fajardo
- Instituto de Investigación Interdisciplinario (I3), Universidad de Talca, Campus Lircay Talca 3460000 Chile
| | - Frida I. Piper
- Instituto de Investigación Interdisciplinario (I3), Universidad de Talca, Campus Lircay Talca 3460000 Chile
| | - Ana I. García‐Cervigón
- Departamento de Biología, Geología, Física y Química Inorgánica, Universidad Rey Juan Carlos, c/Tulipán s/n Móstoles 28933 Spain
| |
Collapse
|
27
|
Lira-Martins D, Quesada CA, Strekopytov S, Humphreys-Williams E, Herault B, Lloyd J. Wood Nutrient-Water-Density Linkages Are Influenced by Both Species and Environment. FRONTIERS IN PLANT SCIENCE 2022; 13:778403. [PMID: 35444675 PMCID: PMC9014131 DOI: 10.3389/fpls.2022.778403] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/16/2021] [Accepted: 02/11/2022] [Indexed: 06/14/2023]
Abstract
Tropical trees store a large amount of nutrients in their woody tissues, thus triggering the question of what the functional association of these elements with other wood traits is. Given the osmotic activity of mineral elements such as potassium, sodium, and calcium, these elements should be strong candidates in mediating the water storing capacity in tropical trees. We investigated the role of wood nutrients in facilitating wood water storage in trees by using branch samples from 48 tropical tree species in South America and examined their associations with wood density (ρ). Wood density varied from 316 kg/m3 in Peru plots, where the soil nutrient status is relatively higher, to 908 kg/m3 in Brazil plots, where the nutrient availability is lower. Phosphorus content in wood varied significantly between plots with lowest values found in French Guiana (1.2 mol/m3) and plots with highest values found in Peru (43.6 mol/m3). Conversely, potassium in woody tissues showed a significant cross-species variation with Minquartia guianensis in Brazil showing the lowest values (8.8 mol/m3) and with Neea divaricata in Peru having the highest values (114 mol/m3). We found that lower wood density trees store more water in their woody tissues with cations, especially potassium, having a positive association with water storage. Specific relationships between wood cation concentrations and stem water storage potential nevertheless depend on both species' identity and growing location. Tropical trees with increased water storage capacity show lower wood density and have an increased reliance on cations to regulate this reservoir. Our study highlights that cations play a more important role in tropical tree water relations than has previously been thought, with potassium being particularly important.
Collapse
Affiliation(s)
- Demetrius Lira-Martins
- Department of Life Sciences, Imperial College London, London, United Kingdom
- Department of Plant Biology, Institute of Biology, University of Campinas (UNICAMP), Campinas, Brazil
| | - Carlos Alberto Quesada
- Coordination of Environmental Dynamics, National Institute for Amazonian Research (INPA), Manaus, Brazil
| | - Stanislav Strekopytov
- Imaging and Analysis Centre, Natural History Museum, London, United Kingdom
- National Measurement Laboratory, LGC, Teddington, United Kingdom
| | | | - Bruno Herault
- UR Forests and Societies, Centre de Coopération Internationale en Recherche Agronomique Pour le Développement (Cirad), Montpellier, France
- Université de Montpellier, Montpellier, France
- Institut National Polytechnique Félix Houphouët-Boigny, Yamoussoukro, Ivory Coast
| | - Jon Lloyd
- Department of Life Sciences, Imperial College London, London, United Kingdom
- Centre for Tropical, Environmental and Sustainability Sciences, College of Science and Engineering, James Cook University, Smithfield, QLD, Australia
- Faculdade de Filosofia, Ciencias e Letras de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, Brazil
| |
Collapse
|
28
|
Zhang G, Mao Z, Fortunel C, Martínez-Vilalta J, Viennois G, Maillard P, Stokes A. Parenchyma fractions drive the storage capacity of nonstructural carbohydrates across a broad range of tree species. AMERICAN JOURNAL OF BOTANY 2022; 109:535-549. [PMID: 35266560 DOI: 10.1002/ajb2.1838] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2021] [Accepted: 02/17/2022] [Indexed: 06/14/2023]
Abstract
PREMISE Nonstructural carbohydrates (NSCs) play a key role in tree performance and functioning and are stored in radial and axial parenchyma (RAP) cells. Whether this relationship is altered among species and climates or is linked to functional traits describing xylem structure (wood density) and tree stature is not known. METHODS In a systematic review, we collated data for NSC content and the proportion of RAP in stems for 68 tree species. To examine the relationships of NSCs and RAP with climatic factors and other functional traits, we also collected climatic data at each tree's location, as well as wood density and maximum height. A phylogenetic tree was constructed to examine the influence of species' evolutionary relationships on the associations among NSCs, RAP, and functional traits. RESULTS Across all 68 tree species, NSCs were positively correlated with RAP and mean annual temperature, but relationships were only weakly significant in temperate species and angiosperms. When separating RAP into radial parenchyma (RP) and axial parenchyma (AP), both NSCs and wood density were positively correlated with RP but not with AP. Wood in taller trees was less dense and had lower RAP than in shorter trees, but height was not related to NSCs. CONCLUSIONS In trees, NSCs are stored mostly in the RP fraction, which has a larger surface area in warmer climates. Additionally, NSCs were only weakly linked to wood density and tree height. Our analysis of evolutionary relationships demonstrated that RAP fractions and NSC content were always closely related across all 68 tree species, suggesting that RAP can act as a reliable proxy for potential NSC storage capacity in tree stems.
Collapse
Affiliation(s)
- Guangqi Zhang
- AMAP, Univ Montpellier, CIRAD, CNRS, INRAE, IRD, 34000 Montpellier, France
| | - Zhun Mao
- AMAP, Univ Montpellier, CIRAD, CNRS, INRAE, IRD, 34000 Montpellier, France
| | - Claire Fortunel
- AMAP, Univ Montpellier, CIRAD, CNRS, INRAE, IRD, 34000 Montpellier, France
| | - Jordi Martínez-Vilalta
- CREAF, E08193 Bellaterra (Cerdanyola del Vallès), Catalonia, Spain
- Universitat Autònoma Barcelona, E08193 Bellaterra (Cerdanyola del Vallès), Catalonia, Spain
| | - Gaëlle Viennois
- AMAP, Univ Montpellier, CIRAD, CNRS, INRAE, IRD, 34000 Montpellier, France
| | - Pascale Maillard
- SILVA, INRAE, Université de Lorraine, Agroparistech, Centre de Recherche Grand-Est Nancy, 54280 Champenoux, France
| | - Alexia Stokes
- AMAP, Univ Montpellier, CIRAD, CNRS, INRAE, IRD, 34000 Montpellier, France
| |
Collapse
|
29
|
Giles AL, Rowland L, Bittencourt PRL, Bartholomew DC, Coughlin I, Costa PB, Domingues T, Miatto RC, Barros FV, Ferreira LV, Groenendijk P, Oliveira AAR, da Costa ACL, Meir P, Mencuccini M, Oliveira RS. Small understorey trees have greater capacity than canopy trees to adjust hydraulic traits following prolonged experimental drought in a tropical forest. TREE PHYSIOLOGY 2022; 42:537-556. [PMID: 34508606 DOI: 10.1093/treephys/tpab121] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Accepted: 09/08/2021] [Indexed: 06/13/2023]
Abstract
Future climate change predictions for tropical forests highlight increased frequency and intensity of extreme drought events. However, it remains unclear whether large and small trees have differential strategies to tolerate drought due to the different niches they occupy. The future of tropical forests is ultimately dependent on the capacity of small trees (<10 cm in diameter) to adjust their hydraulic system to tolerate drought. To address this question, we evaluated whether the drought tolerance of neotropical small trees can adjust to experimental water stress and was different from tall trees. We measured multiple drought resistance-related hydraulic traits across nine common neotropical genera at the world's longest-running tropical forest throughfall-exclusion experiment and compared their responses with surviving large canopy trees. Small understorey trees in both the control and the throughfall-exclusion treatment had lower minimum stomatal conductance and maximum hydraulic leaf-specific conductivity relative to large trees of the same genera, as well as a greater hydraulic safety margin (HSM), percentage loss of conductivity and embolism resistance, demonstrating that they occupy a distinct hydraulic niche. Surprisingly, in response to the drought treatment, small trees increased specific hydraulic conductivity by 56.3% and leaf:sapwood area ratio by 45.6%. The greater HSM of small understorey trees relative to large canopy trees likely enabled them to adjust other aspects of their hydraulic systems to increase hydraulic conductivity and take advantage of increases in light availability in the understorey resulting from the drought-induced mortality of canopy trees. Our results demonstrate that differences in hydraulic strategies between small understorey and large canopy trees drive hydraulic niche segregation. Small understorey trees can adjust their hydraulic systems in response to changes in water and light availability, indicating that natural regeneration of tropical forests following long-term drought may be possible.
Collapse
Affiliation(s)
- A L Giles
- Instituto de Biologia, University of Campinas (UNICAMP), R. Monteiro Lobato, 255 - Barão Geraldo, Campinas SP 13083-970, Brazil
| | - L Rowland
- College of Life and Environmental Sciences, University of Exeter, Exeter EX4 4RJ, UK
| | - P R L Bittencourt
- College of Life and Environmental Sciences, University of Exeter, Exeter EX4 4RJ, UK
| | - D C Bartholomew
- College of Life and Environmental Sciences, University of Exeter, Exeter EX4 4RJ, UK
| | - I Coughlin
- Departamento de Biologia, FFCLRP, Universidade de São Paulo, Av. Bandeirantes, 3900 - Vila Monte Alegre, Ribeirão Preto SP 14040-900, Brazil
- Research School of Biology, Australian National University, 134 Linnaeus Way, Canberra ACT 2601, Australia
| | - P B Costa
- Instituto de Biologia, University of Campinas (UNICAMP), R. Monteiro Lobato, 255 - Barão Geraldo, Campinas SP 13083-970, Brazil
- Biological Sciences, Stirling Highway, Perth, WA 6009, Australia
| | - T Domingues
- Departamento de Biologia, FFCLRP, Universidade de São Paulo, Av. Bandeirantes, 3900 - Vila Monte Alegre, Ribeirão Preto SP 14040-900, Brazil
| | - R C Miatto
- Departamento de Biologia, FFCLRP, Universidade de São Paulo, Av. Bandeirantes, 3900 - Vila Monte Alegre, Ribeirão Preto SP 14040-900, Brazil
| | - F V Barros
- College of Life and Environmental Sciences, University of Exeter, Exeter EX4 4RJ, UK
| | - L V Ferreira
- Museu Paraense Emílio Goeldi, Av. Gov Magalhães Barata, 376 - São Brás, Belém PA 66040-170, Brazil
| | - P Groenendijk
- Instituto de Biologia, University of Campinas (UNICAMP), R. Monteiro Lobato, 255 - Barão Geraldo, Campinas SP 13083-970, Brazil
| | - A A R Oliveira
- Museu Paraense Emílio Goeldi, Av. Gov Magalhães Barata, 376 - São Brás, Belém PA 66040-170, Brazil
| | - A C L da Costa
- Museu Paraense Emílio Goeldi, Av. Gov Magalhães Barata, 376 - São Brás, Belém PA 66040-170, Brazil
- Biological Sciences, Stirling Highway, Perth, WA 6009, Australia
| | - P Meir
- Research School of Biology, Australian National University, 134 Linnaeus Way, Canberra ACT 2601, Australia
- School of GeoSciences, University of Edinburgh, Drummond St Edinburgh EH9 3FF, UK
| | - M Mencuccini
- CREAF, Campus UAB, Edifici C Campus de Bellaterra Cerdanyola del Vallés 08193, Spain
- ICREA, Passeig de Lluís Companys, 23, Barcelona 08010, Spain
| | - R S Oliveira
- Instituto de Biologia, University of Campinas (UNICAMP), R. Monteiro Lobato, 255 - Barão Geraldo, Campinas SP 13083-970, Brazil
| |
Collapse
|
30
|
Weithmann G, Link RM, Banzragch BE, Würzberg L, Leuschner C, Schuldt B. Soil water availability and branch age explain variability in xylem safety of European beech in Central Europe. Oecologia 2022; 198:629-644. [PMID: 35212818 PMCID: PMC8956530 DOI: 10.1007/s00442-022-05124-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2021] [Accepted: 01/24/2022] [Indexed: 12/17/2022]
Abstract
Xylem embolism resistance has been identified as a key trait with a causal relation to drought-induced tree mortality, but not much is known about its intra-specific trait variability (ITV) in dependence on environmental variation. We measured xylem safety and efficiency in 300 European beech (Fagus sylvatica L.) trees across 30 sites in Central Europe, covering a precipitation reduction from 886 to 522 mm year−1. A broad range of variables that might affect embolism resistance in mature trees, including climatic and soil water availability, competition, and branch age, were examined. The average P50 value varied by up to 1 MPa between sites. Neither climatic aridity nor structural variables had a significant influence on P50. However, P50 was less negative for trees with a higher soil water storage capacity, and positively related to branch age, while specific conductivity (Ks) was not significantly associated with either of these variables. The greatest part of the ITV for xylem safety and efficiency was attributed to random variability within populations. We conclude that the influence of site water availability on P50 and Ks is low in European beech, and that the high degree of within-population variability for P50, partly due to variation in branch age, hampers the identification of a clear environmental signal.
Collapse
Affiliation(s)
- Greta Weithmann
- Plant Ecology, Albrecht Von Haller Institute for Plant Sciences, University of Goettingen, Untere Karspüle 2, 37073, Göttingen, Germany
| | - Roman M Link
- Plant Ecology, Albrecht Von Haller Institute for Plant Sciences, University of Goettingen, Untere Karspüle 2, 37073, Göttingen, Germany.,Ecophysiology and Vegetation Ecology, Julius-von-Sachs-Institute of Biological Sciences, University of Würzburg, Julius-von-Sachs-Platz, 97082, Würzburg, Germany
| | - Bat-Enerel Banzragch
- Plant Ecology, Albrecht Von Haller Institute for Plant Sciences, University of Goettingen, Untere Karspüle 2, 37073, Göttingen, Germany
| | - Laura Würzberg
- Plant Ecology, Albrecht Von Haller Institute for Plant Sciences, University of Goettingen, Untere Karspüle 2, 37073, Göttingen, Germany
| | - Christoph Leuschner
- Plant Ecology, Albrecht Von Haller Institute for Plant Sciences, University of Goettingen, Untere Karspüle 2, 37073, Göttingen, Germany.,Centre for Biodiversity and Sustainable Land Use (CBL), University of Goettingen, 37075, Göttingen, Germany
| | - Bernhard Schuldt
- Plant Ecology, Albrecht Von Haller Institute for Plant Sciences, University of Goettingen, Untere Karspüle 2, 37073, Göttingen, Germany. .,Ecophysiology and Vegetation Ecology, Julius-von-Sachs-Institute of Biological Sciences, University of Würzburg, Julius-von-Sachs-Platz, 97082, Würzburg, Germany.
| |
Collapse
|
31
|
Zheng J, Li Y, Morris H, Vandelook F, Jansen S. Variation in Tracheid Dimensions of Conifer Xylem Reveals Evidence of Adaptation to Environmental Conditions. FRONTIERS IN PLANT SCIENCE 2022; 13:774241. [PMID: 35251072 PMCID: PMC8893226 DOI: 10.3389/fpls.2022.774241] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/11/2021] [Accepted: 01/25/2022] [Indexed: 06/14/2023]
Abstract
Globally distributed extant conifer species must adapt to various environmental conditions, which would be reflected in their xylem structure, especially in the tracheid characteristics of earlywood and latewood. With an anatomical trait dataset of 78 conifer species growing throughout China, an interspecific study within a phylogenetic context was conducted to quantify variance of tracheid dimensions and their response to climatic and soil conditions. There was a significant difference in tracheid diameter between earlywood and latewood while no significant difference was detected in tracheid wall thickness through a phylogenetically paired t-test. Through a phylogenetic principle component analysis, Pinaceae species were found to be strongly divergent in their tracheid structure in contrast to a conservative tracheid structure in species of Cupressaceae, Taxaceae, and Podocarpaceae. Tracheid wall thickness decreased from high to low latitudes in both earlywood and latewood, with tracheid diameter decreasing for latewood only. According to the most parsimonious phylogenetic general least square models, environment and phylogeny together could explain about 21∼56% of tracheid structure variance. Our results provide insights into the effects of climate and soil on the xylem structure of conifer species thus furthering our understanding of the trees' response to global change.
Collapse
Affiliation(s)
- Jingming Zheng
- Beijing Key Laboratory for Forest Resources and Ecosystem Processes, School of Ecology and Nature Conservation, Beijing Forestry University, Beijing, China
| | - Yajin Li
- Beijing Key Laboratory for Forest Resources and Ecosystem Processes, School of Ecology and Nature Conservation, Beijing Forestry University, Beijing, China
| | - Hugh Morris
- Department of Integrative Biology and Biodiversity Research, Institute of Botany, University of Natural Resources and Life Sciences, Vienna, Austria
| | - Filip Vandelook
- Living Collections Department, Meise Botanic Garden, Meise, Belgium
| | - Steven Jansen
- Institute of Systematic Botany and Ecology, Ulm University, Ulm, Germany
| |
Collapse
|
32
|
Cabon A, Anderegg WRL. Turgor-driven tree growth: scaling-up sink limitations from the cell to the forest. TREE PHYSIOLOGY 2022; 42:225-228. [PMID: 34788863 DOI: 10.1093/treephys/tpab146] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/03/2021] [Accepted: 11/02/2021] [Indexed: 06/13/2023]
Affiliation(s)
- Antoine Cabon
- School of Biological Sciences, University of Utah, Salt Lake City, UT84113, USA
| | | |
Collapse
|
33
|
Bok ECPM, Brodribb TJ, Jordan GJ, Carriquí M. Convergent tip-to-base widening of water-conducting conduits in the tallest bryophytes. AMERICAN JOURNAL OF BOTANY 2022; 109:322-332. [PMID: 34713894 DOI: 10.1002/ajb2.1795] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/16/2021] [Revised: 10/02/2021] [Accepted: 10/26/2021] [Indexed: 06/13/2023]
Abstract
PREMISE Tip-to-base conduit widening is considered a key mechanism that enables vascular plants to grow tall by decreasing the hydraulic resistance imposed by increasing height. Widening of hydraulic anatomy (larger conducting elements toward the base of the vascular system) minimizes gradients in leaf-specific hydraulic conductance with plant height, allowing uniform photosynthesis across the crown of trees. Tip-to-base conduit widening has also been associated with changes in conduit number. However, in bryophytes, despite having representatives with internal water-conducting tissue, conduit widening has been scarcely investigated. METHODS Here, we examined the changes in hydroid diameter and number with distance from plant tip in Dawsonia superba and D. polytrichoides, two representatives of the genus containing the tallest extant bryophytes. RESULTS The position of these moss species on the global scale of conduit size and plant size was consistent with a general scaling among plants with internal water transport. Within plants, patterns of conduit widening and number with distance from plant tip in endohydric mosses were similar to those observed in vascular plants. CONCLUSIONS This study demonstrated that land plants growing upward in the atmosphere show analogous conduit widening of hydraulic structures, suggesting that efficient internal water transport is a convergent adaptation for photosynthesis on land.
Collapse
Affiliation(s)
- Erin C P M Bok
- Biological Sciences, University of Tasmania, Hobart, Tasmania, Australia
| | - Timothy J Brodribb
- Biological Sciences, University of Tasmania, Hobart, Tasmania, Australia
| | - Gregory J Jordan
- Biological Sciences, University of Tasmania, Hobart, Tasmania, Australia
| | - Marc Carriquí
- Biological Sciences, University of Tasmania, Hobart, Tasmania, Australia
- Department of Biology, University of the Balearic Islands, Palma, Illes Balears, Spain
| |
Collapse
|
34
|
Climate variability supersedes grazing to determine the anatomy and physiology of a dominant grassland species. Oecologia 2022; 198:345-355. [PMID: 35018484 PMCID: PMC8858925 DOI: 10.1007/s00442-022-05106-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2021] [Accepted: 01/03/2022] [Indexed: 10/29/2022]
Abstract
Grassland ecosystems are historically shaped by climate, fire, and grazing which are essential ecological drivers. These grassland drivers influence morphology and productivity of grasses via physiological processes, resulting in unique water and carbon-use strategies among species and populations. Leaf-level physiological responses in plants are constrained by the underlying anatomy, previously shown to reflect patterns of carbon assimilation and water-use in leaf tissues. However, the magnitude to which anatomy and physiology are impacted by grassland drivers remains unstudied. To address this knowledge gap, we sampled from three locations along a latitudinal gradient in the mesic grassland region of the central Great Plains, USA during the 2018 (drier) and 2019 (wetter) growing seasons. We measured annual biomass and forage quality at the plot level, while collecting physiological and anatomical traits at the leaf-level in cattle grazed and ungrazed locations at each site. Effects of ambient drought conditions superseded local grazing treatments and reduced carbon assimilation and total productivity in A. gerardii. Leaf-level anatomical traits, particularly those associated with water-use, varied within and across locations and between years. Specifically, xylem area increased when water was more available (2019), while xylem resistance to cavitation was observed to increase in the drier growing season (2018). Our results highlight the importance of multi-year studies in natural systems and how trait plasticity can serve as vital tool and offer insight to understanding future grassland responses from climate change as climate played a stronger role than grazing in shaping leaf physiology and anatomy.
Collapse
|
35
|
McMann N, Peichel A, Savage JA. Early spring flowers rely on xylem hydration but are not limited by stem xylem conductivity. THE NEW PHYTOLOGIST 2022; 233:838-850. [PMID: 34618926 DOI: 10.1111/nph.17782] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/08/2021] [Accepted: 09/13/2021] [Indexed: 06/13/2023]
Abstract
Many woody plants produce large floral displays early in the spring when xylem transport can be variable and often reduced. To determine whether stem hydraulics impact floral water use, we quantified floral transpiration and tested whether it was correlated with stem xylem conductivity in five temperate woody species that flower before producing leaves. We measured inflorescence gas exchange, examined the relationship between diffusive conductance and inflorescence morphology, and estimated the amount of water supplied to an inflorescence by the phloem. We also tested for correlation between transpiration and native stem xylem conductivity for branches with leaves and branches with flowers. The flowers of our study species obtain most of their water from the xylem. Diffusive conductance was higher in small inflorescences, but water content and daily transpiration rates were greater for larger inflorescences. We found no correlation between floral transpiration per branch and stem xylem conductivity within species. The data suggest that inflorescence water loss during anthesis is not limited by the xylem in our study species. We highlight the impact of floral morphology on hydraulic traits and encourage exploration into temporal shifts in floral hydration.
Collapse
Affiliation(s)
- Natalie McMann
- Department of Biology, University of Minnesota Duluth, 207 Swenson Science Building, 1035 Kirby Drive, Duluth, MN, 55812, USA
| | - Alexander Peichel
- Department of Biology, University of Minnesota Duluth, 207 Swenson Science Building, 1035 Kirby Drive, Duluth, MN, 55812, USA
| | - Jessica A Savage
- Department of Biology, University of Minnesota Duluth, 207 Swenson Science Building, 1035 Kirby Drive, Duluth, MN, 55812, USA
| |
Collapse
|
36
|
Held M, Ganthaler A, Lintunen A, Oberhuber W, Mayr S. Tracheid and Pit Dimensions Hardly Vary in the Xylem of Pinus sylvestris Under Contrasting Growing Conditions. FRONTIERS IN PLANT SCIENCE 2021; 12:786593. [PMID: 34992621 PMCID: PMC8725801 DOI: 10.3389/fpls.2021.786593] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Accepted: 11/16/2021] [Indexed: 06/14/2023]
Abstract
Maintaining sufficient water transport via the xylem is crucial for tree survival under variable environmental conditions. Both efficiency and safety of the water transport are based on the anatomical structure of conduits and their connections, the pits. Yet, the plasticity of the xylem anatomy, particularly that of the pit structures, remains unclear. Also, trees adjust conduit dimensions to the water transport distance (i.e., tree size), but knowledge on respective adjustments in pit dimensions is scarce. We compared tracheid traits [mean tracheid diameter d, mean hydraulic diameter d h , cell wall reinforcement (t/b)2], pit dimensions (diameters of pit aperture D a , torus D t , margo D m , and pit border D p ), and pit functional properties (margo flexibility F, absolute overlap O a , torus overlap O, and valve effect V ef ) of two Scots pine (Pinus sylvestris L.) stands of similar tree heights but contrasting growth rates. Furthermore, we analyzed the trends of these xylem anatomical parameters across tree rings. Tracheid traits and pit dimensions were similar on both sites, whereas O a , O, and F were higher at the site with a lower growth rate. On the lower growth rate site, d h and pit dimensions increased across tree rings from pith to bark, and in trees from both sites, d h scaled with pit dimensions. Adjusted pit functional properties indicate slightly higher hydraulic safety in trees with a lower growth rate, although a lack of major differences in measured traits indicated overall low plasticity of the tracheid and pit architecture. Mean hydraulic diameter and pit dimension are well coordinated to increase the hydraulic efficiency toward the outer tree rings and thus with increasing tree height. Our results contribute to a better understanding of tree hydraulics under variable environmental conditions.
Collapse
Affiliation(s)
- Magdalena Held
- Department of Botany, University of Innsbruck, Innsbruck, Austria
- Institute for Atmospheric and Earth System Research (INAR)/Forest Sciences, University of Helsinki, Helsinki, Finland
| | - Andrea Ganthaler
- Department of Botany, University of Innsbruck, Innsbruck, Austria
| | - Anna Lintunen
- Institute for Atmospheric and Earth System Research (INAR)/Forest Sciences, University of Helsinki, Helsinki, Finland
| | - Walter Oberhuber
- Department of Botany, University of Innsbruck, Innsbruck, Austria
| | - Stefan Mayr
- Department of Botany, University of Innsbruck, Innsbruck, Austria
| |
Collapse
|
37
|
Levionnois S, Salmon C, Alméras T, Clair B, Ziegler C, Coste S, Stahl C, González-Melo A, Heinz C, Heuret P. Anatomies, vascular architectures, and mechanics underlying the leaf size-stem size spectrum in 42 Neotropical tree species. JOURNAL OF EXPERIMENTAL BOTANY 2021; 72:7957-7969. [PMID: 34390333 DOI: 10.1093/jxb/erab379] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/05/2021] [Accepted: 08/13/2021] [Indexed: 06/13/2023]
Abstract
The leaf size-stem size spectrum is one of the main dimensions of plant ecological strategies. Yet the anatomical, mechanical, and hydraulic implications of small versus large shoots are still poorly understood. We investigated 42 tropical rainforest tree species in French Guiana, with a wide range of leaf areas at the shoot level. We quantified the scaling of hydraulic and mechanical constraints with shoot size, estimated as the water potential difference (ΔΨ) and the bending angle (ΔΦ), respectively. We investigated how anatomical tissue area, flexural stiffness and xylem vascular architecture affect such scaling by deviating (or not) from theoretical isometry with shoot size variation. Vessel diameter and conductive path length were found to be allometrically related to shoot size, thereby explaining the independence between ΔΨ and shoot size. Leaf mass per area, stem length, and the modulus of elasticity were allometrically related to shoot size, explaining the independence between ΔΦ and shoot size. Our study also shows that the maintenance of both water supply and mechanical stability across the shoot size range are not in conflict.
Collapse
Affiliation(s)
- Sébastien Levionnois
- UMR EcoFoG, AgroParisTech, CIRAD, CNRS, INRAE, Université des Antilles, Université de Guyane, 97310 Kourou, France
- UMR AMAP, Université de Montpellier, CIRAD, CNRS, INRAE, IRD, Université de Montpellier, 34000 Montpellier, France
| | - Camille Salmon
- UMR AMAP, Université de Montpellier, CIRAD, CNRS, INRAE, IRD, Université de Montpellier, 34000 Montpellier, France
| | - Tancrède Alméras
- LMGC, CNRS, Université de Montpellier, 34090 Montpellier, France
| | - Bruno Clair
- LMGC, CNRS, Université de Montpellier, 34090 Montpellier, France
| | - Camille Ziegler
- UMR EcoFoG, AgroParisTech, CIRAD, CNRS, INRAE, Université des Antilles, Université de Guyane, 97310 Kourou, France
- UMR SILVA, INRAE, Université de Lorraine, 54000 Nancy, France
| | - Sabrina Coste
- UMR EcoFoG, AgroParisTech, CIRAD, CNRS, INRAE, Université des Antilles, Université de Guyane, 97310 Kourou, France
| | - Clément Stahl
- UMR EcoFoG, AgroParisTech, CIRAD, CNRS, INRAE, Université des Antilles, Université de Guyane, 97310 Kourou, France
| | | | - Christine Heinz
- UMR AMAP, Université de Montpellier, CIRAD, CNRS, INRAE, IRD, Université de Montpellier, 34000 Montpellier, France
| | - Patrick Heuret
- UMR AMAP, Université de Montpellier, CIRAD, CNRS, INRAE, IRD, Université de Montpellier, 34000 Montpellier, France
| |
Collapse
|
38
|
Baer AB, Fickle JC, Medina J, Robles C, Pratt RB, Jacobsen AL. Xylem biomechanics, water storage, and density within roots and shoots of an angiosperm tree species. JOURNAL OF EXPERIMENTAL BOTANY 2021; 72:7984-7997. [PMID: 34410349 DOI: 10.1093/jxb/erab384] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/03/2021] [Accepted: 08/17/2021] [Indexed: 06/13/2023]
Abstract
Xylem is a complex tissue that forms the bulk of tree bodies and has several functions, including to conduct water, store water and nutrients, and biomechanically support the plant body. We examined how xylem functional traits varied at different positions within 9-year-old Populus balsamifera subsp. trichocarpa. Whole trees were excavated, and xylem samples were collected at 1-m increments along the main root-to-shoot axis of six trees, from root tip to shoot tip. We examined biomechanical and water-storage traits of the xylem, including using a non-invasive imaging technique to examine water content within long, intact branches (high-resolution computed tomography; microCT). Xylem density, strength, and stiffness were greater in shoots than roots. Along the main root-to-shoot axis, xylem strength and stiffness were greatest at shoot tips, and the tissue became linearly weaker and less stiff down the plant and through the root. Roots had greater water storage with lower biomechanical support, and shoots had biomechanically stronger and stiffer xylem with lower water storage. These findings support trade-offs among xylem functions between roots and shoots. Understanding how xylem functions differ throughout tree bodies is important in understanding whole-tree functioning and how terrestrial plants endure numerous environmental challenges over decades of growth.
Collapse
Affiliation(s)
- Alex B Baer
- Department of Biology, California State University, Bakersfield, CA, 93311, USA
| | - Jaycie C Fickle
- Department of Biology, California State University, Bakersfield, CA, 93311, USA
| | - Jackeline Medina
- Department of Biology, California State University, Bakersfield, CA, 93311, USA
| | - Catherine Robles
- Department of Biology, California State University, Bakersfield, CA, 93311, USA
| | - R Brandon Pratt
- Department of Biology, California State University, Bakersfield, CA, 93311, USA
| | - Anna L Jacobsen
- Department of Biology, California State University, Bakersfield, CA, 93311, USA
| |
Collapse
|
39
|
Kašpar J, Šamonil P, Krůček M, Vašíčková I, Daněk P. Hillslope Processes Affect Vessel Lumen Area and Tree Dimensions. FRONTIERS IN PLANT SCIENCE 2021; 12:778802. [PMID: 34925420 PMCID: PMC8678277 DOI: 10.3389/fpls.2021.778802] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/17/2021] [Accepted: 11/03/2021] [Indexed: 06/14/2023]
Abstract
The height growth of the trees depends on sufficient mechanical support given by the stem and an effective hydraulic system. On unstable slopes, tree growth is affected by soil pressure from above and potential soil erosion from below the position of tree. The necessary stabilization is then provided by the production of mechanically stronger wood of reduced hydraulic conductivity. Unfortunately, the interaction between tree growth (both radial and axial) and stabilization in the soil is still insufficiently understood. Therefore, in this study, we aimed to quantify the impact of hillslope dynamics on the degree of tree growth and hydraulic limitation, and the potential effect on tree height growth and growth plasticity. To evaluate this effect, we took four cores from 80 individuals of Quercus robur and Fraxinus excelsior and measured tree-ring widths (TRWs) and vessel lumen areas (VLAs). The tree heights were evaluated using a terrestrial laser scanner, and local soil depth was measured by a soil auger. Our data showed a significant limitation of the tree hydraulic system related with the formation of eccentric tree-rings. The stem eccentricity decreased with increasing stem diameter, but at the same time, the negative effect of stem eccentricity on conduit size increased with the increasing stem diameter. Even though this anatomical adaptation associated with the effect of stem eccentricity differed between the tree species (mainly in the different degree of limitations in conduit size), the trees showed an increase in the proportion of hydraulically inactive wood elements and a lowered effectiveness of their hydraulic system. In addition, we observed a larger negative effect of stem eccentricity on VLA in Quercus. We conclude that the stabilization of a tree in unstable soil is accompanied by an inability to create sufficiently effective hydraulic system, resulting in severe height-growth limitation. This affects the accumulation of aboveground biomass and carbon sequestration.
Collapse
Affiliation(s)
- Jakub Kašpar
- Department of Forest Ecology, The Silva Tarouca Research Institute, Brno, Czechia
| | - Pavel Šamonil
- Department of Forest Ecology, The Silva Tarouca Research Institute, Brno, Czechia
- Department of Forest Botany, Dendrology and Geobiocoenology, Faculty of Forestry and Wood Technology, Mendel University in Brno, Brno, Czechia
| | - Martin Krůček
- Department of Forest Ecology, The Silva Tarouca Research Institute, Brno, Czechia
| | - Ivana Vašíčková
- Department of Forest Ecology, The Silva Tarouca Research Institute, Brno, Czechia
| | - Pavel Daněk
- Department of Forest Ecology, The Silva Tarouca Research Institute, Brno, Czechia
- Department of Botany and Zoology, Faculty of Science, Masaryk University, Brno, Czechia
| |
Collapse
|
40
|
Onyenedum JG, Pace MR. The role of ontogeny in wood diversity and evolution. AMERICAN JOURNAL OF BOTANY 2021; 108:2331-2355. [PMID: 34761812 DOI: 10.1002/ajb2.1801] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/28/2021] [Accepted: 09/16/2021] [Indexed: 06/13/2023]
Abstract
Evolutionary developmental biology (evo-devo) explores the link between developmental patterning and phenotypic change through evolutionary time. In this review, we highlight the scientific advancements in understanding xylem evolution afforded by the evo-devo approach, opportunities for further engagement, and future research directions for the field. We review evidence that (1) heterochrony-the change in rate and timing of developmental events, (2) homeosis-the ontogenetic replacement of features, (3) heterometry-the change in quantity of a feature, (4) exaptation-the co-opting and repurposing of an ancestral feature, (5) the interplay between developmental and capacity constraints, and (6) novelty-the emergence of a novel feature, have all contributed to generating the diversity of woods. We present opportunities for future research engagement, which combine wood ontogeny within the context of robust phylogenetic hypotheses, and molecular biology.
Collapse
Affiliation(s)
- Joyce G Onyenedum
- School of Integrative Plant Sciences and L. H. Bailey Hortorium, Cornell University, Ithaca, New York, 14853, USA
| | - Marcelo R Pace
- Department of Botany, Instituto de Biología, Universidad Nacional Autónoma de México, Tercer Circuito s/n de Ciudad Universitaria, Mexico City, 04510, Mexico
| |
Collapse
|
41
|
Xu H, Wang H, Prentice IC, Harrison SP, Wright IJ. Coordination of plant hydraulic and photosynthetic traits: confronting optimality theory with field measurements. THE NEW PHYTOLOGIST 2021; 232:1286-1296. [PMID: 34324717 PMCID: PMC9291854 DOI: 10.1111/nph.17656] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/22/2021] [Accepted: 07/26/2021] [Indexed: 05/13/2023]
Abstract
Close coupling between water loss and carbon dioxide uptake requires coordination of plant hydraulics and photosynthesis. However, there is still limited information on the quantitative relationships between hydraulic and photosynthetic traits. We propose a basis for these relationships based on optimality theory, and test its predictions by analysis of measurements on 107 species from 11 sites, distributed along a nearly 3000-m elevation gradient. Hydraulic and leaf economic traits were less plastic, and more closely associated with phylogeny, than photosynthetic traits. The two sets of traits were linked by the sapwood to leaf area ratio (Huber value, vH ). The observed coordination between vH and sapwood hydraulic conductivity (KS ) and photosynthetic capacity (Vcmax ) conformed to the proposed quantitative theory. Substantial hydraulic diversity was related to the trade-off between KS and vH . Leaf drought tolerance (inferred from turgor loss point, -Ψtlp ) increased with wood density, but the trade-off between hydraulic efficiency (KS ) and -Ψtlp was weak. Plant trait effects on vH were dominated by variation in KS , while effects of environment were dominated by variation in temperature. This research unifies hydraulics, photosynthesis and the leaf economics spectrum in a common theoretical framework, and suggests a route towards the integration of photosynthesis and hydraulics in land-surface models.
Collapse
Affiliation(s)
- Huiying Xu
- Ministry of Education Key Laboratory for Earth System ModelingDepartment of Earth System ScienceTsinghua UniversityBeijing100084China
- Joint Center for Global Change Studies (JCGCS)Beijing100875China
| | - Han Wang
- Ministry of Education Key Laboratory for Earth System ModelingDepartment of Earth System ScienceTsinghua UniversityBeijing100084China
- Joint Center for Global Change Studies (JCGCS)Beijing100875China
| | - I. Colin Prentice
- Ministry of Education Key Laboratory for Earth System ModelingDepartment of Earth System ScienceTsinghua UniversityBeijing100084China
- Department of Life SciencesGeorgina Mace Centre for the Living PlanetImperial College LondonSilwood Park Campus, Buckhurst RoadAscotSL5 7PYUK
- Department of Biological SciencesMacquarie UniversityNorth RydeNSW2109Australia
| | - Sandy P. Harrison
- Ministry of Education Key Laboratory for Earth System ModelingDepartment of Earth System ScienceTsinghua UniversityBeijing100084China
- School of Archaeology, Geography and Environmental Sciences (SAGES)University of ReadingReadingRG6 6AHUK
| | - Ian J. Wright
- Department of Biological SciencesMacquarie UniversityNorth RydeNSW2109Australia
| |
Collapse
|
42
|
Mashukov DA, Ben’kova AV, Ben’kova VE, Shashkin AV, Prokushkin AS. Distribution of Tracheid Lumen Areas within Annual Rings at Different Heights of Larch Stem under Permafrost Conditions. Crown Dieback. RUSS J ECOL+ 2021. [DOI: 10.1134/s1067413621050106] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
|
43
|
Frankiewicz KE, Banasiak Ł, Oskolski AA, Magee AR, Alsarraf M, Trzeciak P, Spalik K. Derived woodiness and annual habit evolved in African umbellifers as alternative solutions for coping with drought. BMC PLANT BIOLOGY 2021; 21:383. [PMID: 34416875 PMCID: PMC8377965 DOI: 10.1186/s12870-021-03151-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/03/2021] [Accepted: 07/28/2021] [Indexed: 06/13/2023]
Abstract
BACKGROUND One of the major trends in angiosperm evolution was the shift from woody to herbaceous habit. However, reversals known as derived woodiness have also been reported in numerous, distantly related clades. Among theories evoked to explain the factors promoting the evolution of derived woodiness are moderate climate theory and cavitation theory. The first assumes that woody habit evolves in response to mild climate allowing for prolonged life span, which in turn leads to bigger and woodier bodies. The second sees woodiness as a result of natural selection for higher cavitation resistance in seasonally dry environments. Here, we compare climatic niches of woody and herbaceous, mostly southern African, umbellifers from the Lefebvrea clade to assess whether woody taxa in fact occur in markedly drier habitats. We also calibrate their phylogeny to estimate when derived woodiness evolved. Finally, we describe the wood anatomy of selected woody and herbaceous taxa to see if life forms are linked to any particular wood traits. RESULTS The evolution of derived woodiness in chamaephytes and phanerophytes as well as the shifts to short-lived annual therophytes in the Lefebvrea clade took place at roughly the same time: in the Late Miocene during a trend of global climate aridification. Climatic niches of woody and herbaceous genera from the Cape Floristic Region overlap. There are only two genera with distinctly different climatic preferences: they are herbaceous and occur outside of the Cape Floristic Region. Therefore, studied herbs have an overall climatic niche wider than their woody cousins. Woody and herbaceous species do not differ in qualitative wood anatomy, which is more affected by stem architecture and, probably, reproductive strategy than by habit. CONCLUSIONS Palaeodrought was likely a stimulus for the evolution of derived woodiness in the Lefebvrea clade, supporting the cavitation theory. The concurrent evolution of short-lived annuals withering before summer exemplifies an alternative solution to the same problem of drought-induced cavitation. Changes of the life form were most likely neither spurred nor precluded by any qualitative wood traits, which in turn are more affected by internode length and probably also reproductive strategy.
Collapse
Affiliation(s)
- Kamil E Frankiewicz
- Institute of Evolutionary Biology, Faculty of Biology, University of Warsaw, Biological and Chemical Research Centre, Żwirki i Wigury 101, 02-089, Warsaw, Poland.
| | - Łukasz Banasiak
- Institute of Evolutionary Biology, Faculty of Biology, University of Warsaw, Biological and Chemical Research Centre, Żwirki i Wigury 101, 02-089, Warsaw, Poland
| | - Alexei A Oskolski
- Department of Botany and Plant Biotechnology, University of Johannesburg, PO Box 524, Auckland Park, Johannesburg, 2006, South Africa
- Komarov Botanical Institute, Prof. Popov 2, 197376, St. Petersburg, Russia
| | - Anthony R Magee
- Department of Botany and Plant Biotechnology, University of Johannesburg, PO Box 524, Auckland Park, Johannesburg, 2006, South Africa
- Compton Herbarium, South African National Biodiversity Institute, Kirstenbosch Research Centre, Rhodes Drive, Cape Town, 7700, South Africa
| | - Mohammad Alsarraf
- Institute of Evolutionary Biology, Faculty of Biology, University of Warsaw, Biological and Chemical Research Centre, Żwirki i Wigury 101, 02-089, Warsaw, Poland
| | - Paulina Trzeciak
- Faculty of Biology and Veterinary Sciences, Nicolaus Copernicus University, Lwowska 1, 87-100, Toruń, Poland
| | - Krzysztof Spalik
- Institute of Evolutionary Biology, Faculty of Biology, University of Warsaw, Biological and Chemical Research Centre, Żwirki i Wigury 101, 02-089, Warsaw, Poland
| |
Collapse
|
44
|
Yang D, Zhang Y, Zhou D, Zhang YJ, Peng G, Tyree MT. The hydraulic architecture of an arborescent monocot: ontogeny-related adjustments in vessel size and leaf area compensate for increased resistance. THE NEW PHYTOLOGIST 2021; 231:273-284. [PMID: 33621370 DOI: 10.1111/nph.17294] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/27/2020] [Accepted: 02/15/2021] [Indexed: 06/12/2023]
Abstract
Bamboos are arborescent monocotyledons that have no secondary growth, but can continually produce conduits with diameters appropriate to the current size of the plant. Here, we studied bamboo hydraulic architecture to address the mechanisms involved in compensating for the increase in hydraulic resistance during ontogeny. We measured the hydraulic weighted vessel diameters (Dh ) at different distances from the apex along the stem of Bambusa textilis. The hydraulic resistance of different components and individuals of different heights were quantified using the high-pressure flowmeter method. The Dh showed tip-to-base widening with a scaling exponent in the range of those reported for trees. Although theoretical hydraulic conductivity decreased from base-to-tip, leaf-specific conductivity did not change. Leaves contributed the most to the whole-shoot hydraulic resistance, followed by the leaf-bearing branches. Roots contributed c. 13% to whole-plant resistance. Interestingly, taller individuals showed lower whole-shoot resistance owing to an increased number of resistances in parallel (side-branches), while leaf-specific resistance was independent of plant size. Tip-to-base vessel widening and height-independent constant leaf-specific conductance could be mechanisms for hydraulic optimization in B. textilis. Similar patterns have also been found in woody plants with secondary growth, but this bamboo exhibits them without secondary growth.
Collapse
Affiliation(s)
- Dongmei Yang
- College of Chemistry and Life Sciences, Zhejiang Normal University, Jinhua, Zhejiang, 321004, China
| | - Yinshuang Zhang
- College of Chemistry and Life Sciences, Zhejiang Normal University, Jinhua, Zhejiang, 321004, China
| | - Dan Zhou
- College of Chemistry and Life Sciences, Zhejiang Normal University, Jinhua, Zhejiang, 321004, China
| | - Yong-Jiang Zhang
- School of Biology and Ecology, University of Maine, Orono, ME, 04469, USA
| | - Guoquan Peng
- College of Chemistry and Life Sciences, Zhejiang Normal University, Jinhua, Zhejiang, 321004, China
| | - Melvin T Tyree
- College of Chemistry and Life Sciences, Zhejiang Normal University, Jinhua, Zhejiang, 321004, China
| |
Collapse
|
45
|
Abstract
Shaping global water and carbon cycles, plants lift water from roots to leaves through xylem conduits. The importance of xylem water conduction makes it crucial to understand how natural selection deploys conduit diameters within and across plants. Wider conduits transport more water but are likely more vulnerable to conduction-blocking gas embolisms and cost more for a plant to build, a tension necessarily shaping xylem conduit diameters along plant stems. We build on this expectation to present the Widened Pipe Model (WPM) of plant hydraulic evolution, testing it against a global dataset. The WPM predicts that xylem conduits should be narrowest at the stem tips, widening quickly before plateauing toward the stem base. This universal profile emerges from Pareto modeling of a trade-off between just two competing vectors of natural selection: one favoring rapid widening of conduits tip to base, minimizing hydraulic resistance, and another favoring slow widening of conduits, minimizing carbon cost and embolism risk. Our data spanning terrestrial plant orders, life forms, habitats, and sizes conform closely to WPM predictions. The WPM highlights carbon economy as a powerful vector of natural selection shaping plant function. It further implies that factors that cause resistance in plant conductive systems, such as conduit pit membrane resistance, should scale in exact harmony with tip-to-base conduit widening. Furthermore, the WPM implies that alterations in the environments of individual plants should lead to changes in plant height, for example, shedding terminal branches and resprouting at lower height under drier climates, thus achieving narrower and potentially more embolism-resistant conduits.
Collapse
|
46
|
Garcia LF, Silva GP, Geremia EV, Goulart LBL, Dias CTDS, da Silva SC. Central rib and the nutritive value of leaves in forage grasses. Sci Rep 2021; 11:5440. [PMID: 33686178 PMCID: PMC7940471 DOI: 10.1038/s41598-021-84844-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Accepted: 02/22/2021] [Indexed: 11/16/2022] Open
Abstract
In grasses, leaf expansion and central rib growth occur in a non-proportional manner, with potential implications to the nutritive value of leaves. The objective of this study was to evaluate the relationship among blade length, percentage of central rib, anatomical characteristics and the nutritive value along the length of leaf blades of different sizes and hierarchical order of insertion on the tiller axis of Napier elephant grass (Pennisetum purpureum Schum. cv. Napier). Two experiments were carried out with isolated growing plants during the summer of 2017 (January to March). Central rib mass increased linearly with the increase in leaf blade mass and its percentage relative to blade mass decreased from the base to the tip of the leaf. There were no significant variations in anatomical characteristics along the length of leaf blades when central rib was not taken into account. The central rib showed negative relationship with nutritive value. The apical portions of long leaves showed similar digestibility to short leaves. The multivariate analysis of Cluster and Principal Components grouped the response variables according to leaf hierarchical order, final blade length and percentage of structural tissues, highlighting the relationship between leaf size, structural tissues and nutritive value.
Collapse
Affiliation(s)
- Larissa Fernanda Garcia
- Animal Science Department, University of Sao Paulo, "Luiz de Queiroz" College of Agriculture (USP/ESALQ), Av. Pádua Dias, 11, Piracicaba, Sao Paulo, 13418-900, Brazil.
| | - Guilherme Portes Silva
- Animal Science Department, University of Sao Paulo, "Luiz de Queiroz" College of Agriculture (USP/ESALQ), Av. Pádua Dias, 11, Piracicaba, Sao Paulo, 13418-900, Brazil
| | - Eliana Vera Geremia
- Animal Science Department, University of Sao Paulo, "Luiz de Queiroz" College of Agriculture (USP/ESALQ), Av. Pádua Dias, 11, Piracicaba, Sao Paulo, 13418-900, Brazil
| | - Laura Beatriz Lima Goulart
- Animal Science Department, University of Sao Paulo, "Luiz de Queiroz" College of Agriculture (USP/ESALQ), Av. Pádua Dias, 11, Piracicaba, Sao Paulo, 13418-900, Brazil
| | - Carlos Tadeu Dos Santos Dias
- Math, Chemistry and Statistics Department, University of Sao Paulo, "Luiz de Queiroz" College of Agriculture (USP/ESALQ), Av. Pádua Dias, 11, Piracicaba, Sao Paulo, 13418-900, Brazil.,Soil Science Department, University of Ceara, Campus do Pici. Bloco 807, Av. Mister Hull, s/n, Fortaleza, CE, 60455-760, Brazil
| | - Sila Carneiro da Silva
- Animal Science Department, University of Sao Paulo, "Luiz de Queiroz" College of Agriculture (USP/ESALQ), Av. Pádua Dias, 11, Piracicaba, Sao Paulo, 13418-900, Brazil
| |
Collapse
|
47
|
Effects of Intra-Seasonal Drought on Kinetics of Tracheid Differentiation and Seasonal Growth Dynamics of Norway Spruce along an Elevational Gradient. FORESTS 2021. [DOI: 10.3390/f12030274] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Research Highlights: Our results provide novel perspectives on the effectiveness and collapse of compensatory mechanisms of tracheid development of Norway spruce during intra-seasonal drought and the environmental control of intra-annual density fluctuations. Background and Objectives: This study aimed to compare and integrate complementary methods for investigating intra-annual wood formation dynamics to gain a better understanding of the endogenous and environmental control of tree-ring development and the impact of anticipated climatic changes on forest growth and productivity. Materials and Methods: We performed an integrated analysis of xylogenesis observations, quantitative wood anatomy, and point-dendrometer measurements of Norway spruce (Picea abies (L.) Karst.) trees growing along an elevational gradient in South-western Germany during a growing season with an anomalous dry June followed by an extraordinary humid July. Results: Strong endogenous control of tree-ring formation was suggested at the highest elevation where the decreasing rates of tracheid enlargement and wall thickening during drought were effectively compensated by increased cell differentiation duration. A shift to environmental control of tree-ring formation during drought was indicated at the lowest elevation, where we detected absence of compensatory mechanisms, eventually stimulating the formation of an intra-annual density fluctuation. Transient drought stress in June also led to bimodal patterns and decreasing daily rates of stem radial displacement, radial xylem growth, and woody biomass production. Comparing xylogenesis data with dendrometer measurements showed ambivalent results and it appears that, with decreasing daily rates of radial xylem growth, the signal-to-noise ratio in dendrometer time series between growth and fluctuations of tree water status becomes increasingly detrimental. Conclusions: Our study provides new perspectives into the complex interplay between rates and durations of tracheid development during dry-wet cycles, and, thereby, contributes to an improved and mechanistic understanding of the environmental control of wood formation processes, leading to the formation of intra-annual density fluctuations in tree-rings of Norway spruce.
Collapse
|
48
|
Olson ME. The comparative method is not macroevolution: across-species evidence for within-species process. Syst Biol 2021; 70:1272-1281. [PMID: 33410880 DOI: 10.1093/sysbio/syaa086] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2019] [Revised: 10/28/2020] [Accepted: 11/03/2020] [Indexed: 11/14/2022] Open
Abstract
It is common for studies that employ the comparative method for the study of adaptation, i.e. documentation of potentially adaptive across-species patterns of trait-environment or trait-trait correlation, to be designated as "macroevolutionary." Authors are justified in using "macroevolution" in this way by appeal to definitions such as "evolution above the species level." I argue that regarding the comparative method as "macroevolutionary" is harmful because it hides in serious ways the true causal content of hypotheses tested with the comparative method. The comparative method is a means of testing hypotheses of adaptation and their alternatives. Adaptation is a population level phenomenon, involving heritable interindividual variation that is associated with fitness differences. For example, given heritable intrapopulational variation, more streamlined individuals in populations of fast-moving aquatic animals have higher locomotory efficiency and thus better survivorship and more resources directed to reproduction than less streamlined ones. Direct evidence consistent with this population-level scenario includes the observation that many unrelated species of fast-moving aquatic animals have similar streamlined shapes, an example of the comparative method. Crucial to note in this example is that although the data are observed across species, the comparative method for studying adaptation tests hypotheses regarding standard population-level natural selection with no content that can be construed as "macro." Even less "macro," individual-level developmental dynamics can limit or bias the range of variants available for selection. Calling any of these studies "macroevolutionary" implies that some additional process is at work, shrouding the need to test adaptation hypotheses and study the range of variants that can be produced in development.
Collapse
Affiliation(s)
- Mark E Olson
- Instituto de Biología, Universidad Nacional Autónoma de México, Tercer Circuito sn de Ciudad Universitaria, Ciudad de México, Mexico
| |
Collapse
|