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Wigley BJ, Coetsee C, February EC, Dobelmann S, Higgins SI. Will trees or grasses profit from changing rainfall regimes in savannas? THE NEW PHYTOLOGIST 2024; 241:2379-2394. [PMID: 38245858 DOI: 10.1111/nph.19538] [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: 07/20/2023] [Accepted: 12/19/2023] [Indexed: 01/22/2024]
Abstract
Increasing rainfall variability is widely expected under future climate change scenarios. How will savanna trees and grasses be affected by growing season dry spells and altered seasonality and how tightly coupled are tree-grass phenologies with rainfall? We measured tree and grass responses to growing season dry spells and dry season rainfall. We also tested whether the phenologies of 17 deciduous woody species and the Soil Adjusted Vegetation Index of grasses were related to rainfall between 2019 and 2023. Tree and grass growth was significantly reduced during growing season dry spells. Tree growth was strongly related to growing season soil water potentials and limited to the wet season. Grasses can rapidly recover after growing season dry spells and grass evapotranspiration was significantly related to soil water potentials in both the wet and dry seasons. Tree leaf flushing commenced before the rainfall onset date with little subsequent leaf flushing. Grasses grew when moisture became available regardless of season. Our findings suggest that increased dry spell length and frequency in the growing season may slow down tree growth in some savannas, which together with longer growing seasons may allow grasses an advantage over C3 plants that are advantaged by rising CO2 levels.
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Affiliation(s)
- Benjamin J Wigley
- Plant Ecology, University of Bayreuth, Universitaetsstrasse 30, 95447, Bayreuth, Germany
- School of Natural Resource Management, Nelson Mandela University, George Campus, George, 6530, South Africa
- Savanna Node, Scientific Services, SANParks, Skukuza, 1350, South Africa
| | - Corli Coetsee
- School of Natural Resource Management, Nelson Mandela University, George Campus, George, 6530, South Africa
- Savanna Node, Scientific Services, SANParks, Skukuza, 1350, South Africa
| | - Edmund C February
- Department of Biological Sciences, University of Cape Town, HW Pearson Building, University Ave N, Rondebosch, Cape Town, 7701, South Africa
| | - Svenja Dobelmann
- Department of Remote Sensing, Institute of Geography, Julius-Maximilians-Universitaet Wuerzburg, 97074, Wuerzburg, Germany
| | - Steven I Higgins
- Plant Ecology, University of Bayreuth, Universitaetsstrasse 30, 95447, Bayreuth, Germany
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Zheng Z, Zhou F, Fonti P, Ren P, Li X, Miao G, Dong Z, Fang K. Intra-Annual Wood Formation of Cryptomeria fortunei and Cunninghamia lanceolata in Humid Subtropical China. Front Ecol Evol 2021. [DOI: 10.3389/fevo.2021.733974] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Monitoring cambial activity is important for a better understanding of the mechanisms governing xylem growth responses to climate change, providing a scientific basis for tree-ring-based climate reconstructions and projections about tree growth under future climate scenarios. It plays an even more important role in investigating evergreen tree growth in regions with less distinct seasonal cycles. Subtropical evergreen forests have been studied in recent years for their sensitivity to climate change, but it remains unclear how xylem growth is driven by subtropical climates. To further understand the climate-growth response strategies of subtropical conifers, we micro-cored Cryptomeria fortunei and Cunninghamia lanceolata weekly in 2016 and 2017 at the humid subtropical Gushan Mountain in southeastern China. Our weekly growth monitoring showed that the vegetation periods of these two species were both approximately 2–3 months longer than trees in temperate and boreal forests. The growth of C. fortunei in 2016 and 2017 and C. lanceolata in 2017 showed a bimodal pattern of xylogenesis, which was induced by summer drought. The results also indicated that the earlier end of the xylem formation was related to the yearly drought stress. These findings provide more specific information about tree growth and evidence of how climate influences wood production at the cellular level in subtropical regions.
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Gärtner H, Farahat E. Cambial Activity of Moringa peregrina (Forssk.) Fiori in Arid Environments. FRONTIERS IN PLANT SCIENCE 2021; 12:760002. [PMID: 34795687 PMCID: PMC8592978 DOI: 10.3389/fpls.2021.760002] [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: 08/17/2021] [Accepted: 10/12/2021] [Indexed: 06/13/2023]
Abstract
Moringa peregrina (Forssk.) Fiori, one of 13 species of the Moringaceae family widely distributed throughout the dry tropics, has the potential to become one of the most economically important medicinal plants in Egypt. However, despite its tolerance for drought and heat, it is also threatened by increasing temperatures and decreasing precipitation. Although the phenophase of this species is well documented, almost nothing is known about its period of cambial activity in desert regions. Ring formation and the general environmental adaptability of trees are affected by the timing of cambial activation. In our study site, we observe a distinct coupling of the development of new green leaves at the onset of vegetative growth in October and the phase of cambial activity (November-January). The onset of cambial activity seems to be related to a drop in temperature in October and the onset of torrential rains in the region. There might even be a short phase between the end of cambial activity and the onset of bud formation without xylem formation, but with photosynthetic activity. If so, we assume that all assimilates are stored as non-structural carbohydrates (NSC) in the parenchyma of the new ring. This potential gap opens new questions regarding the correlation between NSC storage capacity and the timing of remobilization for subsequent ring formation.
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Affiliation(s)
- Holger Gärtner
- Dendrosciences, Forest Dynamics, Swiss Federal Research Institute for Forest, Snow and Landscape Research (WSL), Birmensdorf, Switzerland
| | - Emad Farahat
- Botany and Microbiology Department, Faculty of Science, Helwan University, Cairo, Egypt
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Rodriguez-Caton M, Andreu-Hayles L, Morales MS, Daux V, Christie DA, Coopman RE, Alvarez C, Rao MP, Aliste D, Flores F, Villalba R. Different climate sensitivity for radial growth, but uniform for tree-ring stable isotopes along an aridity gradient in Polylepis tarapacana, the world's highest elevation tree species. TREE PHYSIOLOGY 2021; 41:1353-1371. [PMID: 33601406 DOI: 10.1093/treephys/tpab021] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2020] [Revised: 01/22/2021] [Accepted: 02/02/2021] [Indexed: 06/12/2023]
Abstract
Tree growth is generally considered to be temperature limited at upper elevation treelines, yet climate factors controlling tree growth at semiarid treelines are poorly understood. We explored the influence of climate on stem growth and stable isotopes for Polylepis tarapacana Philipi, the world's highest elevation tree species, which is found only in the South American Altiplano. We developed tree-ring width index (RWI), oxygen (δ18O) and carbon (δ13C) chronologies for the last 60 years at four P. tarapacana stands located above 4400 m in elevation, along a 500 km latitude aridity gradient. Total annual precipitation decreased from 300 to 200 mm from the northern to the southern sites. We used RWI as a proxy of wood formation (carbon sink) and isotopic tree-ring signatures as proxies of leaf-level gas exchange processes (carbon source). We found distinct climatic conditions regulating carbon sink processes along the gradient. Current growing-season temperature regulated RWI at northern-wetter sites, while prior growing-season precipitation determined RWI at arid southern sites. This suggests that the relative importance of temperature to precipitation in regulating tree growth is driven by site water availability. By contrast, warm and dry growing seasons resulted in enriched tree-ring δ13C and δ18O at all study sites, suggesting that similar climate conditions control carbon-source processes along the gradient. Site-level δ13C and δ18O chronologies were significantly and positively related at all sites, with the strongest relationships among the southern drier stands. This indicates an overall regulation of intercellular carbon dioxide via stomatal conductance for the entire P. tarapacana network, with greater stomatal control when aridity increases. This manuscript also highlights a coupling (decoupling) between physiological processes at leaf level and wood formation as a function of similarities (differences) in their climatic sensitivity. This study contributes to a better understanding and prediction of the response of high-elevation Polylepis woodlands to rapid climate changes and projected drying in the Altiplano.
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Affiliation(s)
| | - Laia Andreu-Hayles
- Lamont-Doherty Earth Observatory, Columbia University, 61 Route 9W, Palisades, NY 10964, USA
- CREAF, Bellaterra (Cerdanyola del Vallés), Barcelona, Spain
- ICREA, Pg. Lluís Companys 23, Barcelona, Spain
| | - Mariano S Morales
- Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales (IANIGLA), CONICET, Av. Ruiz Leal s/n, Mendoza 5500, Argentina
- Laboratorio de Dendrocronología, Universidad Continental, Av. San Carlos 1980, Huancayo 12003, Perú
| | - Valérie Daux
- Laboratoire des Sciences du Climat et de l'Environnement, CEA/CNRS/UVSQ/IPSL, Gif-sur-Yvette, France
| | - Duncan A Christie
- Laboratorio de Dendrocronología y Cambio Global, Instituto de Conservación Biodiversidad y Territorio, Universidad Austral de Chile, Campus Isla Teja, Valdivia 5110566, Los Ríos, Chile
- Center for Climate and Resilience Research, (CR)2, Blanco Encalada 2002, Santiago 8370415, Chile
| | - Rafael E Coopman
- Ecophysiology Laboratory for Forest Conservation, Instituto de Conservación, Biodiversidad y Territorio, Facultad de Ciencias Forestales y Recursos Naturales, Universidad Austral de Chile, Independencia 631, Valdivia 5110566, Los Ríos, Chile
| | - Claudio Alvarez
- Laboratorio de Dendrocronología y Cambio Global, Instituto de Conservación Biodiversidad y Territorio, Universidad Austral de Chile, Campus Isla Teja, Valdivia 5110566, Los Ríos, Chile
| | - Mukund Palat Rao
- Lamont-Doherty Earth Observatory, Columbia University, 61 Route 9W, Palisades, NY 10964, USA
- Department of Earth and Environmental Sciences, Columbia University, 5th Floor Schermerhorn Extension, 1200 Amsterdam Ave., New York, NY 10027, USA
| | - Diego Aliste
- Laboratorio de Dendrocronología y Cambio Global, Instituto de Conservación Biodiversidad y Territorio, Universidad Austral de Chile, Campus Isla Teja, Valdivia 5110566, Los Ríos, Chile
- Center for Climate and Resilience Research, (CR)2, Blanco Encalada 2002, Santiago 8370415, Chile
| | - Felipe Flores
- Laboratorio de Dendrocronología y Cambio Global, Instituto de Conservación Biodiversidad y Territorio, Universidad Austral de Chile, Campus Isla Teja, Valdivia 5110566, Los Ríos, Chile
| | - Ricardo Villalba
- Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales (IANIGLA), CONICET, Av. Ruiz Leal s/n, Mendoza 5500, Argentina
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Rahman MH, Kudo K, Yamagishi Y, Nakamura Y, Nakaba S, Begum S, Nugroho WD, Arakawa I, Kitin P, Funada R. Winter-spring temperature pattern is closely related to the onset of cambial reactivation in stems of the evergreen conifer Chamaecyparis pisifera. Sci Rep 2020; 10:14341. [PMID: 32868796 PMCID: PMC7458908 DOI: 10.1038/s41598-020-70356-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2019] [Accepted: 06/10/2020] [Indexed: 11/16/2022] Open
Abstract
Temperature is an important factor for the cambial growth in temperate trees. We investigated the way daily temperatures patterns (maximum, average and minimum) from late winter to early spring affected the timing of cambial reactivation and xylem differentiation in stems of the conifer Chamaecyparis pisifera. When the daily temperatures started to increase earlier from late winter to early spring, cambial reactivation occurred earlier. Cambium became active when it achieves the desired accumulated temperature above the threshold (cambial reactivation index; CRI) of 13 °C in 11 days in 2013 whereas 18 days in 2014. This difference in duration required for achieving accumulated temperature can be explained with the variations in the daily temperature patterns in 2013 and 2014. Our formula for calculation of CRI predicted the cambial reactivation in 2015. A hypothetical increase of 1-4 °C to the actual daily maximum temperatures of 2013 and 2014 shifted the timing of cambial reactivation and had different effects on cambial reactivation in the two consecutive years because of variations in the actual daily temperatures patterns. Thus, the specific annual pattern of accumulation of temperature from late winter to early spring is a critical factor in determining the timing of cambial reactivation in trees.
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Affiliation(s)
- Md Hasnat Rahman
- Faculty of Agriculture, Tokyo University of Agriculture and Technology, Fuchu, Tokyo, 183-8509, Japan
- Institute of Global Innovation Research, Tokyo University of Agriculture and Technology, Fuchu, Tokyo, 183-8538, Japan
| | - Kayo Kudo
- Institute of Wood Technology, Akita Prefectural University, Noshiro, Akita, 016-0876, Japan
| | - Yusuke Yamagishi
- Research Faculty of Agriculture, Hokkaido University, Sapporo, 060-8589, Japan
| | - Yusuke Nakamura
- Faculty of Agriculture, Tokyo University of Agriculture and Technology, Fuchu, Tokyo, 183-8509, Japan
| | - Satoshi Nakaba
- Faculty of Agriculture, Tokyo University of Agriculture and Technology, Fuchu, Tokyo, 183-8509, Japan
- Institute of Global Innovation Research, Tokyo University of Agriculture and Technology, Fuchu, Tokyo, 183-8538, Japan
| | - Shahanara Begum
- Faculty of Agriculture, Bangladesh Agricultural University, Mymensingh, 2202, Bangladesh
| | - Widyanto Dwi Nugroho
- Faculty of Forestry, Universitas Gadjah Mada, Jalan Agro No. 1 Bulaksumur, Yogyakarta, 55281, Indonesia
| | - Izumi Arakawa
- Faculty of Agriculture, Tokyo University of Agriculture and Technology, Fuchu, Tokyo, 183-8509, Japan
- Institute of Global Innovation Research, Tokyo University of Agriculture and Technology, Fuchu, Tokyo, 183-8538, Japan
| | - Peter Kitin
- Institute of Global Innovation Research, Tokyo University of Agriculture and Technology, Fuchu, Tokyo, 183-8538, Japan
- Department of Bacteriology, University of Wisconsin, Madison, WI, 53706, USA
| | - Ryo Funada
- Faculty of Agriculture, Tokyo University of Agriculture and Technology, Fuchu, Tokyo, 183-8509, Japan.
- Institute of Global Innovation Research, Tokyo University of Agriculture and Technology, Fuchu, Tokyo, 183-8538, Japan.
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Kitin P, Nakaba S, Hunt CG, Lim S, Funada R. Direct fluorescence imaging of lignocellulosic and suberized cell walls in roots and stems. AOB PLANTS 2020; 12:plaa032. [PMID: 32793329 PMCID: PMC7415075 DOI: 10.1093/aobpla/plaa032] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/13/2020] [Accepted: 06/21/2020] [Indexed: 05/05/2023]
Abstract
Investigating plant structure is fundamental in botanical science and provides crucial knowledge for the theories of plant evolution, ecophysiology and for the biotechnological practices. Modern plant anatomy often targets the formation, localization and characterization of cellulosic, lignified or suberized cell walls. While classical methods developed in the 1960s are still popular, recent innovations in tissue preparation, fluorescence staining and microscopy equipment offer advantages to the traditional practices for investigation of the complex lignocellulosic walls. Our goal is to enhance the productivity and quality of microscopy work by focusing on quick and cost-effective preparation of thick sections or plant specimen surfaces and efficient use of direct fluorescent stains. We discuss popular histochemical microscopy techniques for visualization of cell walls, such as autofluorescence or staining with calcofluor, Congo red (CR), fluorol yellow (FY) and safranin, and provide detailed descriptions of our own approaches and protocols. Autofluorescence of lignin in combination with CR and FY staining can clearly differentiate between lignified, suberized and unlignified cell walls in root and stem tissues. Glycerol can serve as an effective clearing medium as well as the carrier of FY for staining of suberin and lipids allowing for observation of thick histological preparations. Three-dimensional (3D) imaging of all cell types together with chemical information by wide-field fluorescence or confocal laser scanning microscopy (CLSM) was achieved.
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Affiliation(s)
- Peter Kitin
- School of Environmental and Forest Sciences, University of Washington, Seattle, WA, USA
- Institute of Global Innovation Research, Tokyo University of Agriculture and Technology, Fuchu-Tokyo, Japan
| | - Satoshi Nakaba
- Institute of Global Innovation Research, Tokyo University of Agriculture and Technology, Fuchu-Tokyo, Japan
- Faculty of Agriculture, Tokyo University of Agriculture and Technology, Fuchu-Tokyo, Japan
| | | | - Sierin Lim
- School of Chemical and Biomedical Engineering, Nanyang Technological University, Singapore, Singapore
| | - Ryo Funada
- Institute of Global Innovation Research, Tokyo University of Agriculture and Technology, Fuchu-Tokyo, Japan
- Faculty of Agriculture, Tokyo University of Agriculture and Technology, Fuchu-Tokyo, Japan
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