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Xu S, Su H, Ren S, Hou J, Zhu Y. Functional traits and habitat heterogeneity explain tree growth in a warm temperate forest. Oecologia 2023; 203:371-381. [PMID: 37910255 DOI: 10.1007/s00442-023-05471-1] [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: 11/25/2022] [Accepted: 10/16/2023] [Indexed: 11/03/2023]
Abstract
To explore how traits determine demographic performance is an important goal of plant community ecology in explaining the assembly and dynamics of ecological communities. However, whether the prediction of individual-level trait data is more precise compared to species average trait data is questioned. Here, we analyzed the growth and trait data for 11 species collected from October 2018 to October 2020 in a temperate forest, Donglingshan, Beijing. To quantify the relationships between traits and growth rate, we conducted linear regression models at both the species and individual levels, as well as developed structural equation models at both levels. We found there was a clear difference in growth between the warm and cold seasons, with tree growth mainly concentrated in the warm season. Growth rate was positively correlated with the specific leaf area, while negatively correlated with leaf thickness and wood density without considering environmental information. Adding important contextual information in the analysis of species-level structural equation modeling, growth rates were positively correlated with specific leaf area and leaf thickness. However, in the individual-level, there was a negative correlation between growth rate and wood density. Our study showed that individual-level trait data have better predictions for individual growth than species-level data. When we use multiple traits and establish links between traits and tree size, we generated strong predictive relationships between traits and growth rates. Furthermore, our study highlighted that the importance of incorporating topographical factors and considering different seasons to assess the relationship between tree growth and functional traits.
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Affiliation(s)
- Shuaiwei Xu
- School of Ecology and Nature Conservation, Beijing Forestry University, Beijing, 100083, China
- State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China
| | - Hongxin Su
- Key Laboratory of Environment Change and Resources Use in Beibu Gulf, Ministry of Education, Nanning Normal University, Nanning, 530001, China
| | - Siyuan Ren
- China Aero Geophysical Survey & Remote Sensing Center for Natural Resources, Beijing, 100083, China
| | - Jihua Hou
- School of Ecology and Nature Conservation, Beijing Forestry University, Beijing, 100083, China.
| | - Yan Zhu
- State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China.
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2
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Stegner M, Buchner O, Geßlbauer M, Lindner J, Flörl A, Xiao N, Holzinger A, Gierlinger N, Neuner G. Frozen mountain pine needles: The endodermis discriminates between the ice-containing central tissue and the ice-free fully functional mesophyll. PHYSIOLOGIA PLANTARUM 2023; 175:e13865. [PMID: 36717368 PMCID: PMC10107293 DOI: 10.1111/ppl.13865] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2022] [Revised: 12/22/2022] [Accepted: 01/23/2023] [Indexed: 05/19/2023]
Abstract
Conifer (Pinaceae) needles are the most frost-hardy leaves. During needle freezing, the exceptional leaf anatomy, where an endodermis separates the mesophyll from the vascular tissue, could have consequences for ice management and photosynthesis. The eco-physiological importance of needle freezing behaviour was evaluated based on the measured natural freezing strain at the alpine treeline. Ice localisation and cellular responses to ice were investigated in mountain pine needles by cryo-microscopic techniques. Their consequences for photosynthetic activity were assessed by gas exchange measurements. The freezing response was related to the microchemistry of cell walls investigated by Raman microscopy. In frozen needles, ice was confined to the central vascular cylinder bordered by the endodermis. The endodermal cell walls were lignified. In the ice-free mesophyll, cells showed no freeze-dehydration and were found photosynthetically active. Mesophyll cells had lignified tangential cell walls, which adds rigidity. Ice barriers in mountain pine needles seem to be realised by a specific lignification patterning of cell walls. This, additionally, impedes freeze-dehydration of mesophyll cells and enables gas exchange of frozen needles. At the treeline, where freezing is a dominant environmental factor, the elaborate needle freezing pattern appears of ecological importance.
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Affiliation(s)
| | - Othmar Buchner
- Department of BotanyUniversity of InnsbruckInnsbruckAustria
| | | | - Jasmin Lindner
- Department of BotanyUniversity of InnsbruckInnsbruckAustria
| | | | - Nannan Xiao
- Institute of Biophysics, University of Natural Resources and Life Sciences (BOKU)ViennaAustria
| | | | - Notburga Gierlinger
- Institute of Biophysics, University of Natural Resources and Life Sciences (BOKU)ViennaAustria
| | - Gilbert Neuner
- Department of BotanyUniversity of InnsbruckInnsbruckAustria
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3
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Responses to Climate Change of Maximum Latewood Density from Larix speciosa Cheng et Law and Abies delavayi Franch. in the Northwest of Yunnan Province, China. FORESTS 2022. [DOI: 10.3390/f13050720] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Tree-ring density has been used for climate-response analysis and climate reconstruction for many species. However, our knowledge of wood density for the responses of different species to climate remains very limited and inconclusive. To determine the relationship between maximum latewood density (MXD) and climate for deciduous and evergreen coniferous species, MXD chronologies were developed from Larix speciosa Cheng et Law and Abies delavayi Franch. growing at 3200–3300 m a.s.l. in Gongshan county, northwestern Yunnan, in China. Significant positive correlations with late summer mean temperature were found for the MXD chronologies of both species. However, the highest correlation occurred in August–September for L. speciosa (r = 0.551, p < 0.01) and in September–October for A. delavayi (r = 0.575, p < 0.01), which may be associated with the physiological habits of trees. Linear model can describe relationships between late-summer temperature and MXD index for L. speciosa (MXD = 0.0506T8–9 − 0.0509, R2 = 30.3%) and A. delavay (MXD = 0.0317T9–10 + 0.4066, R2 = 33.0%). The composite chronology from the two species can reveal a late summer temperature (August−October) signal with the explained variance 32.2% for its response model. However, in dry areas and or at high altitudes close to upper tree line, the responses of wood densities to climate require further investigation for deciduous and evergreen coniferous species.
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4
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Temperature Control of Spring CO2 Fluxes at a Coniferous Forest and a Peat Bog in Central Siberia. ATMOSPHERE 2021. [DOI: 10.3390/atmos12080984] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Climate change impacts the characteristics of the vegetation carbon-uptake process in the northern Eurasian terrestrial ecosystem. However, the currently available direct CO2 flux measurement datasets, particularly for central Siberia, are insufficient for understanding the current condition in the northern Eurasian carbon cycle. Here, we report daily and seasonal interannual variations in CO2 fluxes and associated abiotic factors measured using eddy covariance in a coniferous forest and a bog near Zotino, Krasnoyarsk Krai, Russia, for April to early June, 2013–2017. Despite the snow not being completely melted, both ecosystems became weak net CO2 sinks if the air temperature was warm enough for photosynthesis. The forest became a net CO2 sink 7–16 days earlier than the bog. After the surface soil temperature exceeded ~1 °C, the ecosystems became persistent net CO2 sinks. Net ecosystem productivity was highest in 2015 for both ecosystems because of the anomalously high air temperature in May compared with other years. Our findings demonstrate that long-term monitoring of flux measurements at the site level, particularly during winter and its transition to spring, is essential for understanding the responses of the northern Eurasian ecosystem to spring warming.
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Zhirnova DF, Belokopytova LV, Meko DM, Babushkina EA, Vaganov EA. Climate change and tree growth in the Khakass-Minusinsk Depression (South Siberia) impacted by large water reservoirs. Sci Rep 2021; 11:14266. [PMID: 34253791 PMCID: PMC8275609 DOI: 10.1038/s41598-021-93745-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2021] [Accepted: 06/30/2021] [Indexed: 11/23/2022] Open
Abstract
Regional and local climate change depends on continentality, orography, and human activities. In particular, local climate modification by water reservoirs can reach far from shore and downstream. Among the possible ecological consequences are shifts in plant performance. Tree-ring width of affected trees can potentially be used as proxies for reservoir impact. Correlation analysis and t-tests were applied to climatic data and tree-ring chronologies of Pinus sylvestris L. and Larix sibirica Ledeb. from moisture-deficit habitats in the intermontane Khakass-Minusinsk Depression, to assess modification of climate and tree growth by the Krasnoyarsk and Sayano-Shushenskoe Reservoirs on the Yenisei River. Abrupt significant cooling in May–August and warming in September-March occurred after the launch of the turbines in dams, more pronounced near the Sayano-Shushenskoe dam (up to – 0.5 °C in summer and to + 3.5 °C in winter) than near the Krasnoyarsk Reservoir headwaters (– 0.3 °C and + 1.4 °C). Significant lengthening of the warm season was also found for temperature thresholds 0–8 °C. Shifts of seasonality and intensity occurred in climatic responses of all tree-ring chronologies after development of water reservoirs. Patterns of these shifts, however, depended on species-specific sensitivity to climatic modification, distance from reservoirs, and physiographic regions. Mitigation of climate continentality and extremes by reservoirs appears to have offset possible negative effects of warming on tree growth.
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Affiliation(s)
- D F Zhirnova
- Khakass Technical Institute, Siberian Federal University, Abakan, Russia
| | - L V Belokopytova
- Khakass Technical Institute, Siberian Federal University, Abakan, Russia.
| | - D M Meko
- Laboratory of Tree-Ring Research, University of Arizona, Tucson, USA
| | - E A Babushkina
- Khakass Technical Institute, Siberian Federal University, Abakan, Russia
| | - E A Vaganov
- Siberian Federal University, Krasnoyarsk, Russia.,Sukachev Institute of Forest SB RAS, Krasnoyarsk, Russia
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Fréchette E, Chang CYY, Ensminger I. Variation in the phenology of photosynthesis among eastern white pine provenances in response to warming. GLOBAL CHANGE BIOLOGY 2020; 26:5217-5234. [PMID: 32396692 DOI: 10.1111/gcb.15150] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/17/2019] [Accepted: 04/01/2020] [Indexed: 06/11/2023]
Abstract
In higher-latitude trees, temperature and photoperiod control the beginning and end of the photosynthetically active season. Elevated temperature (ET) has advanced spring warming and delayed autumn cooling while photoperiod remains unchanged. We assessed the effects of warming on the length of the photosynthetically active season of three provenances of Pinus strobus L. seedlings from different latitudes, and evaluated the accuracy of the photochemical reflectance index (PRI) and the chlorophyll/carotenoid index (CCI) for tracking the predicted variation in spring and autumn phenology of photosynthesis among provenances. Seedlings from northern, local and southern P. strobus provenances were planted in a temperature-free-air-controlled enhancement (T-FACE) experiment and exposed to ET (+1.5/3°C; day/night). Over 18 months, we assessed photosynthetic phenology by measuring chlorophyll fluorescence, gas exchange, leaf spectral reflectance and pigment content. During autumn, all seedlings regardless of provenance followed the same sequence of phenological events with the initial downregulation of photosynthesis, followed by the modulation of non-photochemical quenching and associated adjustments of zeaxanthin pool sizes. However, the timing of autumn downregulation differed between provenances, with delayed onset in the southern provenance (SP) and earlier onset in the northern relative to the local provenance, indicating that photoperiod at the provenance origin is a dominant factor controlling autumn phenology. Experimental warming further delayed the downregulation of photosynthesis during autumn in the SP. A provenance effect during spring was also observed but was generally not significant. The vegetation indices PRI and CCI were both effective at tracking the seasonal variations of energy partitioning in needles and the differences of carotenoid pigments indicative of the stress status of needles. These results demonstrate that PRI and CCI can be useful tools for monitoring conifer phenology and for the remote monitoring of the length of the photosynthetically active season of conifers in a changing climate.
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Affiliation(s)
- Emmanuelle Fréchette
- Department of Biology, University of Toronto Mississauga, Mississauga, ON, Canada
- Department of Cell and Systems Biology, University of Toronto, Toronto, ON, Canada
| | - Christine Yao-Yun Chang
- Department of Biology, University of Toronto Mississauga, Mississauga, ON, Canada
- Department of Cell and Systems Biology, University of Toronto, Toronto, ON, Canada
| | - Ingo Ensminger
- Department of Biology, University of Toronto Mississauga, Mississauga, ON, Canada
- Department of Cell and Systems Biology, University of Toronto, Toronto, ON, Canada
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, ON, Canada
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7
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Zagirova SV, Mikhaylov OA, Elsakov VV. Carbon Dioxide, Heat, and Water Vapor Fluxes between a Spruce Forest and the Atmosphere in Northeastern European Russia. BIOL BULL+ 2020. [DOI: 10.1134/s1062359020010185] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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8
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Maruta E, Kubota M, Ikeda T. Effects of xylem embolism on the winter survival of Abies veitchii shoots in an upper subalpine region of central Japan. Sci Rep 2020; 10:6594. [PMID: 32313053 PMCID: PMC7171099 DOI: 10.1038/s41598-020-62651-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2019] [Accepted: 03/11/2020] [Indexed: 11/09/2022] Open
Abstract
At high elevations, winter climatic conditions frequently cause excessive drought stress, which can induce embolism in conifer trees. We investigated the formation and repair of winter embolism in subalpine fir (Abies veitchii) growing near the timberline. We found a complete loss in xylem conductivity [100% percent loss of conductivity (PLC)] at the wind-exposed site (W+) and 40% PLC at the wind-protected site (W−). A PLC of 100% was far above the embolism rate expected from the drought-induced vulnerability analysis in the laboratory. At the W+ site, a PLC of 100% was maintained until May; this suddenly decreased to a negligible value in June, whereas the recovery at the W− site started in late winter and proceeded stepwise. The contrast between the two sites may have occurred because of the different underlying mechanisms of winter embolism. If most tracheids in the xylem of 100% PLC are air-filled, it will be difficult to refill quickly. However, embolism caused by pit aspiration could be restored rapidly, because aspirated pits isolate tracheids from each other and prevent the spread of cavitation. Although severe embolism may cause frost damage of needles, it may have a role in holding water within the stem.
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Affiliation(s)
- Emiko Maruta
- Department of Biology, Faculty of Science, Toho University, 2-2-1 Miyama, Funabashi, Chiba, 274-8520, Japan. .,Department of Biological Science, Faculty of Science, Kanagawa University, 2946 Tsuchiya, Hiratsuka, Kanagawa, 259-1293, Japan.
| | - Mitsumasa Kubota
- Department of Bioresource Science, Faculty of Agriculture, Shizuoka University, 836 Oya, Surugaku, Shizuoka, 422-8529, Japan.,Daitou Techuno Green Inc., 1-2-3 Haramachida, Machida, Tokyo, 194-0013, Japan
| | - Takefumi Ikeda
- Department of Forest Science, Graduate School of Life and Environmental Sciences, Kyoto Prefectural University, 1-5 Shimogamohangi-cho, Sakyo-ku, Kyoto, 606-8522, Japan
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9
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Machacova K, Vainio E, Urban O, Pihlatie M. Seasonal dynamics of stem N 2O exchange follow the physiological activity of boreal trees. Nat Commun 2019; 10:4989. [PMID: 31676776 PMCID: PMC6825224 DOI: 10.1038/s41467-019-12976-y] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2018] [Accepted: 10/03/2019] [Indexed: 11/28/2022] Open
Abstract
The role of trees in the nitrous oxide (N2O) balance of boreal forests has been neglected despite evidence suggesting their substantial contribution. We measured seasonal changes in N2O fluxes from soil and stems of boreal trees in Finland, showing clear seasonality in stem N2O flux following tree physiological activity, particularly processes of CO2 uptake and release. Stem N2O emissions peak during the vegetation season, decrease rapidly in October, and remain low but significant to the annual totals during winter dormancy. Trees growing on dry soils even turn to consumption of N2O from the atmosphere during dormancy, thereby reducing their overall N2O emissions. At an annual scale, pine, spruce and birch are net N2O sources, with spruce being the strongest emitter. Boreal trees thus markedly contribute to the seasonal dynamics of ecosystem N2O exchange, and their species-specific contribution should be included into forest emission inventories. Forest soil is known to be a source of the greenhouse gas N2O, but the impact of what is planted in that soil has long been overlooked. Here Machacova and colleagues quantify seasonal N2O fluxes from common boreal tree species in Finland, finding that all trees are net sources of this gas.
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Affiliation(s)
- Katerina Machacova
- Global Change Research Institute of the Czech Academy of Sciences, Belidla 4a, CZ-60300, Brno, Czech Republic.
| | - Elisa Vainio
- Environmental Soil Science, Department of Agricultural Sciences, University of Helsinki, P.O.Box 56, FI-00014, Helsinki, Finland.,Institute for Atmospheric and Earth System Research/Forest Sciences, University of Helsinki, P.O.Box 27, FI-00014, Helsinki, Finland
| | - Otmar Urban
- Global Change Research Institute of the Czech Academy of Sciences, Belidla 4a, CZ-60300, Brno, Czech Republic
| | - Mari Pihlatie
- Environmental Soil Science, Department of Agricultural Sciences, University of Helsinki, P.O.Box 56, FI-00014, Helsinki, Finland.,Institute for Atmospheric and Earth System Research/Forest Sciences, University of Helsinki, P.O.Box 27, FI-00014, Helsinki, Finland.,Viikki Plant Science Centre (ViPS), University of Helsinki, P.O.Box 56, FI-00014, Helsinki, Finland
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10
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Zagirova SV, Mikhailov OA, Elsakov VV. Carbon Dioxide and Water Exchange between Spruce Forest and Atmosphere in Spring—Summer under Different Weather Conditions. CONTEMP PROBL ECOL+ 2019. [DOI: 10.1134/s1995425519010116] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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11
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Adhikari P, Shin MS, Jeon JY, Kim HW, Hong S, Seo C. Potential impact of climate change on the species richness of subalpine plant species in the mountain national parks of South Korea. ACTA ACUST UNITED AC 2018. [DOI: 10.1186/s41610-018-0095-y] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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12
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Ren P, Rossi S, Camarero JJ, Ellison AM, Liang E, Peñuelas J. Critical temperature and precipitation thresholds for the onset of xylogenesis of Juniperus przewalskii in a semi-arid area of the north-eastern Tibetan Plateau. ANNALS OF BOTANY 2018; 121:617-624. [PMID: 29300821 PMCID: PMC5853012 DOI: 10.1093/aob/mcx188] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/03/2017] [Accepted: 11/20/2017] [Indexed: 05/11/2023]
Abstract
Background and Aims The onset of xylogenesis plays an important role in tree growth and carbon sequestration, and it is thus a key variable in modelling the responses of forest ecosystems to climate change. Temperature regulates the resumption of cambial activity, but little is known about the effect of water availability on the onset of xylogenesis in cold but semi-arid regions. Methods The onset of xylogenesis during 2009-2014 was monitored by weekly microcoring Juniperus przewalskii trees at upper and lower treelines on the north-eastern Tibetan Plateau. A logistic regression was used to calculate the probability of xylogenic activity at a given temperature and a two-dimensional reverse Gaussian model to fit the differences between the observed and estimated days of xylogenesis onset at given temperatures and precipitation within a certain time window. Key Results The thermal thresholds at the beginning of the growing season were highly variable, suggesting that temperature was not the only factor initiating xylem growth under cold and dry climatic conditions. The onset of xylogenesis was well predicted for climatic thresholds characterized by a cumulative precipitation of 17.0 ± 5.6 mm and an average minimum temperature of 1.5 ± 1.4 °C for a period of 12 d. Conclusions Xylogenesis in semi-arid regions with dry winters and springs can start when both critical temperature and precipitation thresholds are reached. Such findings contribute to our knowledge of the environmental drivers of growth resumption that previously had been investigated largely in cold regions without water shortages during early growing seasons. Models of the onset of xylogenesis should include water availability to improve predictions of xylem phenology in dry areas. A mismatch between the thresholds of temperature and moisture for the onset of xylogenesis may increase forest vulnerability in semi-arid areas under forecasted warmer and drier conditions.
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Affiliation(s)
- Ping Ren
- Key Laboratory of Alpine Ecology and Biodiversity, Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing, China
- Key Laboratory of Tibetan Environment Changes and Land Surface Processes, Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing, China
| | - Sergio Rossi
- University of Quebec in Chicoutimi, Département des Sciences Fondamentales, Boulevard de l’Université, Canada
- Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, China
| | - J Julio Camarero
- Instituto Pirenaico de Ecología (IPE, CSIC), Avda. Montañana, Zaragoza, Spain
| | | | - Eryuan Liang
- Key Laboratory of Alpine Ecology and Biodiversity, Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing, China
- Key Laboratory of Tibetan Environment Changes and Land Surface Processes, Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing, China
- CAS Centre for Excellence in Tibetan Plateau Earth Sciences, Beijing, China
| | - Josep Peñuelas
- CSIC, Global Ecology Unit CREAF-CSIC-UAB, Bellaterra, Catalonia, Spain
- CREAF, Cerdanyola del Vallès, Catalonia, Spain
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13
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Yu H, Cao J, Chen Z, Shang H. Effects of elevated O 3 on physiological and biochemical responses in three kinds of trees native to subtropical forest in China during non-growing period. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2018; 234:716-725. [PMID: 29245146 DOI: 10.1016/j.envpol.2017.12.012] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2017] [Revised: 12/03/2017] [Accepted: 12/04/2017] [Indexed: 06/07/2023]
Abstract
Numerous studies have documented the negative effects of ozone (O3) on tree species in growing season, however, little is done in non-growing season. Three evergreen tree species, Phoebe bournei (Hemsl.) Yang (P. bournei), Machilus pauhoi Kanehira (M. pauhoi) and Taxus chinensis (Pilger) Rehd (T. chinensis), were exposed to non-filtered air, 100 nmol mol-1 O3 air (E1) and 150 nmol mol-1 O3 air (E2) in open-top chambers in subtropical China. In the entire period of experiment, O3 fumigation decreased net photosynthesis rate (Pn) through stomatal limitation during the transition period from growing to non-growing season (TGN), and through non-stomatal limitation during the period of non-growing season (NGS) in all species tested. Meanwhile, O3 fumigation reduced and delayed the resilience of Pn in all species tested during the transition period from non-growing to growing season (TNG). O3 fumigation significantly decreased chlorophyll contents during NGS, whereas no obvious injury symptoms were observed till the end of experiment. O3 fumigation induced increases in levels of malondialdehyde, superoxide dismutase, total phenolics and reduced ascorbic acid, and changes in four plant endogenous hormones as well in all species tested during NGS. During NGS, E1 and E2 reduced Pn by an average of 80.11% in P. bournei, 94.56% in M. pauhoi and 12.57% in T. chinensis, indicating that the O3 sensitivity was in an order of M. pauhoi > P. bournei > T. chinensis. Overall, O3 fumigation inhibited carbon fixation in all species tested during NGS. Furthermore, O3-induced physiological activities also consumed the dry matter. All these suggested that elevated O3, which is likely to come true during NGS in the future, will adversely affect the accumulation of dry matter and the resilience of Pn during TNG in evergreen tree species, and further inhibit their growth and development in the upcoming growing season.
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Affiliation(s)
- Hao Yu
- Key Laboratory of Forest Ecology and Environment, State Forestry Administration of China, Research Institute of Forest Ecology, Environment and Protection, Chinese Academy of Forestry, Beijing 100091, China
| | - Jixin Cao
- Key Laboratory of Forest Ecology and Environment, State Forestry Administration of China, Research Institute of Forest Ecology, Environment and Protection, Chinese Academy of Forestry, Beijing 100091, China
| | - Zhan Chen
- Key Laboratory of Forest Ecology and Environment, State Forestry Administration of China, Research Institute of Forest Ecology, Environment and Protection, Chinese Academy of Forestry, Beijing 100091, China
| | - He Shang
- Key Laboratory of Forest Ecology and Environment, State Forestry Administration of China, Research Institute of Forest Ecology, Environment and Protection, Chinese Academy of Forestry, Beijing 100091, China.
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14
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Lintunen A, Mayr S, Salmon Y, Cochard H, Hölttä T. Drivers of apoplastic freezing in gymnosperm and angiosperm branches. Ecol Evol 2018; 8:333-343. [PMID: 29321875 PMCID: PMC5756836 DOI: 10.1002/ece3.3665] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2017] [Revised: 11/02/2017] [Accepted: 11/03/2017] [Indexed: 11/11/2022] Open
Abstract
It is not well understood what determines the degree of supercooling of apoplastic sap in trees, although it determines the number and duration of annual freeze-thaw cycles in a given environment. We studied the linkage between apoplastic ice nucleation temperature, tree water status, and conduit size. We used branches of 10 gymnosperms and 16 angiosperms collected from an arboretum in Helsinki (Finland) in winter and spring. Branches with lower relative water content froze at lower temperatures, and branch water content was lower in winter than in spring. A bench drying experiment with Picea abies confirmed that decreasing branch water potential decreases apoplastic ice nucleation temperature. The studied angiosperms froze on average 2.0 and 1.8°C closer to zero Celsius than the studied gymnosperms during winter and spring, respectively. This was caused by higher relative water content in angiosperms; when branches were saturated with water, apoplastic ice nucleation temperature of gymnosperms increased to slightly higher temperature than that of angiosperms. Apoplastic ice nucleation temperature in sampled branches was positively correlated with xylem conduit diameter as shown before, but saturating the branches removed the correlation. Decrease in ice nucleation temperature decreased the duration of freezing, which could have an effect on winter embolism formation via the time available for gas escape during ice propagation. The apoplastic ice nucleation temperature varied not only between branches but also within a branch between consecutive freeze-thaw cycles demonstrating the stochastic nature of ice nucleation.
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Affiliation(s)
- Anna Lintunen
- Department of Forest SciencesUniversity of HelsinkiHelsinkiFinland
- Department of PhysicsUniversity of HelsinkiHelsinkiFinland
| | - Stefan Mayr
- Institute of BotanyUniversity of InnsbruckInnsbruckAustria
| | - Yann Salmon
- Department of PhysicsUniversity of HelsinkiHelsinkiFinland
| | - Hervé Cochard
- University of Clermont‐AuvergneClermont‐FerrandFrance
| | - Teemu Hölttä
- Department of Forest SciencesUniversity of HelsinkiHelsinkiFinland
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Jump AS, Ruiz-Benito P, Greenwood S, Allen CD, Kitzberger T, Fensham R, Martínez-Vilalta J, Lloret F. Structural overshoot of tree growth with climate variability and the global spectrum of drought-induced forest dieback. GLOBAL CHANGE BIOLOGY 2017; 23:3742-3757. [PMID: 28135022 DOI: 10.1111/gcb.13636] [Citation(s) in RCA: 105] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/25/2016] [Accepted: 12/26/2016] [Indexed: 05/25/2023]
Abstract
Ongoing climate change poses significant threats to plant function and distribution. Increased temperatures and altered precipitation regimes amplify drought frequency and intensity, elevating plant stress and mortality. Large-scale forest mortality events will have far-reaching impacts on carbon and hydrological cycling, biodiversity, and ecosystem services. However, biogeographical theory and global vegetation models poorly represent recent forest die-off patterns. Furthermore, as trees are sessile and long-lived, their responses to climate extremes are substantially dependent on historical factors. We show that periods of favourable climatic and management conditions that facilitate abundant tree growth can lead to structural overshoot of aboveground tree biomass due to a subsequent temporal mismatch between water demand and availability. When environmental favourability declines, increases in water and temperature stress that are protracted, rapid, or both, drive a gradient of tree structural responses that can modify forest self-thinning relationships. Responses ranging from premature leaf senescence and partial canopy dieback to whole-tree mortality reduce canopy leaf area during the stress period and for a lagged recovery window thereafter. Such temporal mismatches of water requirements from availability can occur at local to regional scales throughout a species geographical range. As climate change projections predict large future fluctuations in both wet and dry conditions, we expect forests to become increasingly structurally mismatched to water availability and thus overbuilt during more stressful episodes. By accounting for the historical context of biomass development, our approach can explain previously problematic aspects of large-scale forest mortality, such as why it can occur throughout the range of a species and yet still be locally highly variable, and why some events seem readily attributable to an ongoing drought while others do not. This refined understanding can facilitate better projections of structural overshoot responses, enabling improved prediction of changes in forest distribution and function from regional to global scales.
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Affiliation(s)
- Alistair S Jump
- Biological and Environmental Sciences, University of Stirling, Scotland, FK9 4LA, UK
- CREAF, Campus de Bellaterra (UAB), Edifici C, Cerdanyola del Vallès 08193, Catalonia, Spain
| | - Paloma Ruiz-Benito
- Biological and Environmental Sciences, University of Stirling, Scotland, FK9 4LA, UK
- Forest Ecology and Restoration Group, Department of Life Sciences, Science Building, Universidad de Alcalá, Campus Universitario, 28805 Alcalá de Henares, Madrid, Spain
| | - Sarah Greenwood
- Biological and Environmental Sciences, University of Stirling, Scotland, FK9 4LA, UK
| | - Craig D Allen
- U.S. Geological Survey, Fort Collins Science Center, New Mexico Landscapes Field Station, Los Alamos, NM, 87544, USA
| | - Thomas Kitzberger
- Laboratorio Ecotono, INIBIOMA, CONICET-Universidad Nacional del Comahue, Bariloche, 8400, Río Negro, Argentina
| | - Rod Fensham
- Queensland Herbarium, Environmental Protection Agency, Mt Coot-tha Road, Toowong, Qld, 4066, Australia
- School of Biological Sciences, University of Queensland, St Lucia, Qld, 4072, Australia
| | - Jordi Martínez-Vilalta
- CREAF, Campus de Bellaterra (UAB), Edifici C, Cerdanyola del Vallès 08193, Catalonia, Spain
- Autonomous University of Barcelona, Cerdanyola del Vallès 08193, Catalonia, Spain
| | - Francisco Lloret
- CREAF, Campus de Bellaterra (UAB), Edifici C, Cerdanyola del Vallès 08193, Catalonia, Spain
- Autonomous University of Barcelona, Cerdanyola del Vallès 08193, Catalonia, Spain
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16
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Chan AM, Bowling DR. Assessing the thermal dissipation sap flux density method for monitoring cold season water transport in seasonally snow-covered forests. TREE PHYSIOLOGY 2017; 37:984-995. [PMID: 28549168 DOI: 10.1093/treephys/tpx049] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2016] [Accepted: 05/03/2017] [Indexed: 06/07/2023]
Abstract
Productivity of conifers in seasonally snow-covered forests is high before and during snowmelt when environmental conditions are optimal for photosynthesis. Climate change is altering the timing of spring in many locations, and changes in the date of transition from winter dormancy can have large impacts on annual productivity. Sap flow methods provide a promising approach to monitor tree activity during the cold season and the winter-spring and fall-winter transitions. Although sap flow techniques have been widely used, cold season results are generally not reported. Here we examine the feasibility of using the Granier thermal dissipation (TD) sap flux density method to monitor transpiration and dormancy of evergreen conifers during the cold season. We conducted a laboratory experiment which demonstrated that the TD method reliably detects xylem water transport (when it occurs) both at near freezing temperature and at low flow rate, and that the sensors can withstand repeated freeze-thaw events. However, the dependence between sensor output and water transport rate in these experiments differed from the established TD relation. In field experiments, sensors installed in two Abies forests lasted through two winters and a summer with low failure. The baseline (no-flow) sensor output varied considerably with temperature during the cold season, and a new baseline algorithm was developed to accommodate this variation. The Abies forests differed in elevation (2070 and 2620 m), and there was a clear difference in timing of initiation and cessation of transpiration between them. We conclude that the TD method can be reliably used to examine water transport during cold periods with associated low flow conditions.
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Affiliation(s)
- Allison M Chan
- Department of Biology, University of Utah, 257 South 1400 East, Salt Lake City, UT 84112, USA
- Los Alamos National Laboratory, Environmental Management Division, Los Alamos, NM 87545, USA
| | - David R Bowling
- Department of Biology, University of Utah, 257 South 1400 East, Salt Lake City, UT 84112, USA
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Sensitivity of Korean fir ( Abies koreana Wils.), a threatened climate relict species, to increasing temperature at an island subalpine area. Ecol Modell 2017. [DOI: 10.1016/j.ecolmodel.2017.01.018] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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18
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Lintunen A, Lindfors L, Nikinmaa E, Hölttä T. Xylem diameter changes during osmotic stress, desiccation and freezing in Pinus sylvestris and Populus tremula. TREE PHYSIOLOGY 2017; 37:491-500. [PMID: 27998974 DOI: 10.1093/treephys/tpw114] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2016] [Accepted: 10/24/2016] [Indexed: 06/06/2023]
Abstract
Trees experience low apoplastic water potential frequently in most environments. Low apoplastic water potential increases the risk of embolism formation in xylem conduits and creates dehydration stress for the living cells. We studied the magnitude and rate of xylem diameter change in response to decreasing apoplastic water potential and the role of living parenchyma cells in it to better understand xylem diameter changes in different environmental conditions. We compared responses of control and heat-injured xylem of Pinus sylvestris (L.) and Populus tremula (L.) branches to decreasing apoplastic water potential created by osmotic stress, desiccation and freezing. It was shown that xylem in control branches shrank more in response to decreasing apoplastic water potential in comparison with the samples that were preheated to damage living xylem parenchyma. By manipulating the osmotic pressure of the xylem sap, we observed xylem shrinkage due to decreasing apoplastic water potential even in the absence of water tension within the conduits. These results indicate that decreasing apoplastic water potential led to withdrawal of intracellular water from the xylem parenchyma, causing tissue shrinkage. The amount of xylem shrinkage per decrease in apoplastic water potential was higher during osmotic stress or desiccation compared with freezing. During desiccation, xylem diameter shrinkage involved both dehydration-related shrinkage of xylem parenchyma and water tension-induced shrinkage of conduits, whereas dehydration-related shrinkage of xylem parenchyma was accompanied by swelling of apoplastic ice during freezing. It was also shown that the exchange of water between symplast and apoplast within xylem is clearly faster than previously reported between the phloem and the xylem. Time constant of xylem shrinkage was 40 and 2 times higher during osmotic stress than during freezing stress in P. sylvestris and P. tremula, respectively. Finally, it was concluded that the amount of water stored in the xylem parenchyma is an important reservoir for trees to buffer daily fluctuations in water relations.
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Affiliation(s)
- Anna Lintunen
- Department of Forest Sciences, University of Helsinki, P.O. BOX 27, FI-00014 Helsinki, Finland
| | - Lauri Lindfors
- Department of Forest Sciences, University of Helsinki, P.O. BOX 27, FI-00014 Helsinki, Finland
- Department of Physics, University of Helsinki, P.O. BOX 64, FI-00014 Helsinki, Finland
| | - Eero Nikinmaa
- Department of Forest Sciences, University of Helsinki, P.O. BOX 27, FI-00014 Helsinki, Finland
| | - Teemu Hölttä
- Department of Forest Sciences, University of Helsinki, P.O. BOX 27, FI-00014 Helsinki, Finland
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19
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Environmental Factors Effect on Stem Radial Variations of Picea crassifolia in Qilian Mountains, Northwestern China. FORESTS 2016. [DOI: 10.3390/f7100210] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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20
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Liu X, Nie Y, Luo T, Yu J, Shen W, Zhang L. Seasonal Shift in Climatic Limiting Factors on Tree Transpiration: Evidence from Sap Flow Observations at Alpine Treelines in Southeast Tibet. FRONTIERS IN PLANT SCIENCE 2016; 7:1018. [PMID: 27468289 PMCID: PMC4942459 DOI: 10.3389/fpls.2016.01018] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/24/2016] [Accepted: 06/27/2016] [Indexed: 06/06/2023]
Abstract
Alpine and northern treelines are primarily controlled by low temperatures. However, little is known about the impact of low soil temperature on tree transpiration at treelines. We aim to test the hypothesis that in cold-limited forests, the main limiting factors for tree transpiration switch from low soil temperature before summer solstice to atmospheric evaporative demand after summer solstice, which generally results in low transpiration in the early growing season. Sap flow, meteorological factors and predawn needle water potential were continuously monitored throughout one growing season across Smith fir (Abies georgei var. smithii) and juniper (Juniperus saltuaria) treelines in southeast Tibet. Sap flow started in early May and corresponded to a threshold mean air-temperature of 0°C. Across tree species, transpiration was mainly limited by low soil temperature prior to the summer solstice but by vapor pressure deficit and solar radiation post-summer solstice, which was further confirmed on a daily scale. As a result, tree transpiration for both tree species was significantly reduced in the pre-summer solstice period as compared to post-summer solstice, resulting in a lower predawn needle water potential for Smith fir trees in the early growing season. Our data supported the hypothesis, suggesting that tree transpiration mainly responds to soil temperature variations in the early growing season. The results are important for understanding the hydrological response of cold-limited forest ecosystems to climate change.
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Affiliation(s)
- Xinsheng Liu
- College of Tourism and Territorial Resources, Jiujiang University, JiujiangJiangxi Province, China
- Key Laboratory of Alpine Ecology and Biodiversity, Institute of Tibetan Plateau Research, Chinese Academy of SciencesBeijing, China
| | - Yuqin Nie
- College of Tourism and Territorial Resources, Jiujiang University, JiujiangJiangxi Province, China
| | - Tianxiang Luo
- Key Laboratory of Alpine Ecology and Biodiversity, Institute of Tibetan Plateau Research, Chinese Academy of SciencesBeijing, China
- CAS Center for Excellence in Tibetan Plateau Earth SciencesBeijing, China
| | - Jiehui Yu
- Key Laboratory of Alpine Ecology and Biodiversity, Institute of Tibetan Plateau Research, Chinese Academy of SciencesBeijing, China
| | - Wei Shen
- Key Laboratory of Alpine Ecology and Biodiversity, Institute of Tibetan Plateau Research, Chinese Academy of SciencesBeijing, China
| | - Lin Zhang
- Key Laboratory of Alpine Ecology and Biodiversity, Institute of Tibetan Plateau Research, Chinese Academy of SciencesBeijing, China
- CAS Center for Excellence in Tibetan Plateau Earth SciencesBeijing, China
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21
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Evaluating Biosphere Model Estimates of the Start of the Vegetation Active Season in Boreal Forests by Satellite Observations. REMOTE SENSING 2016. [DOI: 10.3390/rs8070580] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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22
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DOrangeville L, Duchesne L, Houle D, Kneeshaw D, Cote B, Pederson N. Northeastern North America as a potential refugium for boreal forests in a warming climate. Science 2016; 352:1452-5. [DOI: 10.1126/science.aaf4951] [Citation(s) in RCA: 91] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2016] [Accepted: 05/19/2016] [Indexed: 11/02/2022]
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23
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Moser JG, Oberbauer SF, Sternberg LDSL, Ellsworth PZ, Starr G, Mortazavi B, Olivas PC. Water uptake of Alaskan tundra evergreens during the winter-spring transition. AMERICAN JOURNAL OF BOTANY 2016; 103:298-306. [PMID: 26823378 DOI: 10.3732/ajb.1500358] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/03/2015] [Accepted: 11/19/2015] [Indexed: 05/26/2023]
Abstract
PREMISE OF THE STUDY The cold season in the Arctic extends over 8 to 9 mo, yet little is known about vascular plant physiology during this period. Evergreen species photosynthesize under the snow, implying that they are exchanging water with the atmosphere. However, liquid water available for plant uptake may be limited at this time. The study objective was to determine whether evergreen plants are actively taking up water while under snow and/or immediately following snowmelt during spring thaw. METHODS In two in situ experiments, one at the plot level and another at the individual species level, (2)H-labeled water was used as a tracer injected beneath the snow, after which plant stems and leaves were tested for the presence of the label. In separate experiments, excised shoots of evergreen species were exposed to (2)H-labeled water for ∼5 s or 60 min and tested for foliar uptake of the label. KEY RESULTS In both the plot-level and the species-level experiments, some (2)H-labeled water was found in leaves and stems. Additionally, excised individual plant shoots exposed to labeled water for 60 min took up significantly more (2)H-label than shoots exposed ∼5 s. CONCLUSIONS Evergreen tundra plants take up water under snow cover, some via roots, but also likely by foliar uptake. The ability to take up water in the subnivean environment allows evergreen tundra plants to take advantage of mild spring conditions under the snow and replenish carbon lost by winter respiration.
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Affiliation(s)
- Jonathan G Moser
- Department of Biological Sciences, Florida International University 11200 SW 8th Street, Miami, Florida 33199 USA
| | - Steven F Oberbauer
- Department of Biological Sciences, Florida International University 11200 SW 8th Street, Miami, Florida 33199 USA
| | - Leonel da S L Sternberg
- Department of Biology, University of Miami, 215 Cox Science Center, 1301 Memorial Drive, Coral Gables, Florida 33124-0421 USA
| | - Patrick Z Ellsworth
- Department of Biology, University of Miami, 215 Cox Science Center, 1301 Memorial Drive, Coral Gables, Florida 33124-0421 USA
| | - Gregory Starr
- Department of Biological Sciences, University of Alabama, Box 870344, Tuscaloosa, Alabama 35487 USA
| | - Behzad Mortazavi
- Dauphin Island Sea Laboratory, 101 Bienville Boulevard, Dauphin Island, Alabama 36528 USA
| | - Paulo C Olivas
- Department of Biological Sciences, Florida International University 11200 SW 8th Street, Miami, Florida 33199 USA
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24
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Charra-Vaskou K, Badel E, Charrier G, Ponomarenko A, Bonhomme M, Foucat L, Mayr S, Améglio T. Cavitation and water fluxes driven by ice water potential in Juglans regia during freeze-thaw cycles. JOURNAL OF EXPERIMENTAL BOTANY 2016; 67:739-50. [PMID: 26585223 PMCID: PMC4737071 DOI: 10.1093/jxb/erv486] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
Freeze-thaw cycles induce major hydraulic changes due to liquid-to-ice transition within tree stems. The very low water potential at the ice-liquid interface is crucial as it may cause lysis of living cells as well as water fluxes and embolism in sap conduits, which impacts whole tree-water relations. We investigated water fluxes induced by ice formation during freeze-thaw cycles in Juglans regia L. stems using four non-invasive and complementary approaches: a microdendrometer, magnetic resonance imaging, X-ray microtomography, and ultrasonic acoustic emissions analysis. When the temperature dropped, ice nucleation occurred, probably in the cambium or pith areas, inducing high water potential gradients within the stem. The water was therefore redistributed within the stem toward the ice front. We could thus observe dehydration of the bark's living cells leading to drastic shrinkage of this tissue, as well as high tension within wood conduits reaching the cavitation threshold in sap vessels. Ultrasonic emissions, which were strictly emitted only during freezing, indicated cavitation events (i.e. bubble formation) following ice formation in the xylem sap. However, embolism formation (i.e. bubble expansion) in stems was observed only on thawing via X-ray microtomography for the first time on the same sample. Ultrasonic emissions were detected during freezing and were not directly related to embolism formation. These results provide new insights into the complex process and dynamics of water movements and ice formation during freeze-thaw cycles in tree stems.
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Affiliation(s)
- Katline Charra-Vaskou
- INRA, UMR PIAF, F-63100 Clermont-Ferrand, France Clermont Université, Blaise Pascal University, UMR PIAF, F-63100 Clermont-Ferrand, France
| | - Eric Badel
- INRA, UMR PIAF, F-63100 Clermont-Ferrand, France Clermont Université, Blaise Pascal University, UMR PIAF, F-63100 Clermont-Ferrand, France
| | - Guillaume Charrier
- Department of Botany, University of Innsbruck, A-6020 Innsbruck, Austria
| | - Alexandre Ponomarenko
- INRA, UMR PIAF, F-63100 Clermont-Ferrand, France Clermont Université, Blaise Pascal University, UMR PIAF, F-63100 Clermont-Ferrand, France
| | - Marc Bonhomme
- INRA, UMR PIAF, F-63100 Clermont-Ferrand, France Clermont Université, Blaise Pascal University, UMR PIAF, F-63100 Clermont-Ferrand, France
| | | | - Stefan Mayr
- Department of Botany, University of Innsbruck, A-6020 Innsbruck, Austria
| | - Thierry Améglio
- INRA, UMR PIAF, F-63100 Clermont-Ferrand, France Clermont Université, Blaise Pascal University, UMR PIAF, F-63100 Clermont-Ferrand, France
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25
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Jensen AM, Warren JM, Hanson PJ, Childs J, Wullschleger SD. Needle age and season influence photosynthetic temperature response and total annual carbon uptake in mature Picea mariana trees. ANNALS OF BOTANY 2015; 116:821-32. [PMID: 26220656 PMCID: PMC4590327 DOI: 10.1093/aob/mcv115] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/06/2014] [Revised: 02/06/2015] [Accepted: 06/22/2015] [Indexed: 05/24/2023]
Abstract
BACKGROUND AND AIMS The carbon (C) balance of boreal terrestrial ecosystems is sensitive to increasing temperature, but the direction and thresholds of responses are uncertain. Annual C uptake in Picea and other evergreen boreal conifers is dependent on seasonal- and cohort-specific photosynthetic and respiratory temperature response functions, so this study examined the physiological significance of maintaining multiple foliar cohorts for Picea mariana trees within an ombrotrophic bog ecosystem in Minnesota, USA. METHODS Measurements were taken on multiple cohorts of needles for photosynthetic capacity, foliar respiration (Rd) and leaf biochemistry and morphology of mature trees from April to October over 4 years. The results were applied to a simple model of canopy photosynthesis in order to simulate annual C uptake by cohort age under ambient and elevated temperature scenarios. KEY RESULTS Temperature responses of key photosynthetic parameters [i.e. light-saturated rate of CO2 assimilation (Asat), rate of Rubisco carboxylation (Vcmax) and electron transport rate (Jmax)] were dependent on season and generally less responsive in the developing current-year (Y0) needles compared with 1-year-old (Y1) or 2-year-old (Y2) foliage. Temperature optimums ranged from 18·7 to 23·7, 31·3 to 38·3 and 28·7 to 36·7 °C for Asat, Vcmax and Jmax, respectively. Foliar cohorts differed in their morphology and photosynthetic capacity, which resulted in 64 % of modelled annual stand C uptake from Y1&2 cohorts (LAI 0·67 m(2 )m(-2)) and just 36 % from Y0 cohorts (LAI 0·52 m(2 )m(-2)). Under warmer climate change scenarios, the contribution of Y0 cohorts was even less; e.g. 31 % of annual C uptake for a modelled 9 °C rise in mean summer temperatures. Results suggest that net annual C uptake by P. mariana could increase under elevated temperature, and become more dependent on older foliar cohorts. CONCLUSIONS Collectively, this study illustrates the physiological and ecological significance of different foliar cohorts, and indicates the need for seasonal- and cohort-specific model parameterization when estimating C uptake capacity of boreal forest ecosystems under ambient or future temperature scenarios.
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Affiliation(s)
- Anna M Jensen
- Climate Change Science Institute, Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831-6301, USA
| | - Jeffrey M Warren
- Climate Change Science Institute, Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831-6301, USA
| | - Paul J Hanson
- Climate Change Science Institute, Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831-6301, USA
| | - Joanne Childs
- Climate Change Science Institute, Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831-6301, USA
| | - Stan D Wullschleger
- Climate Change Science Institute, Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831-6301, USA
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26
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Koo KA, Kong WS, Nibbelink NP, Hopkinson CS, Lee JH. Potential Effects of Climate Change on the Distribution of Cold-Tolerant Evergreen Broadleaved Woody Plants in the Korean Peninsula. PLoS One 2015; 10:e0134043. [PMID: 26262755 PMCID: PMC4532508 DOI: 10.1371/journal.pone.0134043] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2015] [Accepted: 07/04/2015] [Indexed: 12/04/2022] Open
Abstract
Climate change has caused shifts in species' ranges and extinctions of high-latitude and altitude species. Most cold-tolerant evergreen broadleaved woody plants (shortened to cold-evergreens below) are rare species occurring in a few sites in the alpine and subalpine zones in the Korean Peninsula. The aim of this research is to 1) identify climate factors controlling the range of cold-evergreens in the Korean Peninsula; and 2) predict the climate change effects on the range of cold-evergreens. We used multimodel inference based on combinations of climate variables to develop distribution models of cold-evergreens at a physiognomic-level. Presence/absence data of 12 species at 204 sites and 6 climatic factors, selected from among 23 candidate variables, were used for modeling. Model uncertainty was estimated by mapping a total variance calculated by adding the weighted average of within-model variation to the between-model variation. The range of cold-evergreens and model performance were validated by true skill statistics, the receiver operating characteristic curve and the kappa statistic. Climate change effects on the cold-evergreens were predicted according to the RCP 4.5 and RCP 8.5 scenarios. Multimodel inference approach excellently projected the spatial distribution of cold-evergreens (AUC = 0.95, kappa = 0.62 and TSS = 0.77). Temperature was a dominant factor in model-average estimates, while precipitation was minor. The climatic suitability increased from the southwest, lowland areas, to the northeast, high mountains. The range of cold-evergreens declined under climate change. Mountain-tops in the south and most of the area in the north remained suitable in 2050 and 2070 under the RCP 4.5 projection and 2050 under the RCP 8.5 projection. Only high-elevations in the northeastern Peninsula remained suitable under the RCP 8.5 projection. A northward and upper-elevational range shift indicates change in species composition at the alpine and subalpine ecosystems in the Korean Peninsula.
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Affiliation(s)
- Kyung Ah Koo
- National Institute of Ecology, Seocheon-gun, Chungnam, Republic of Korea
| | | | | | | | - Joon Ho Lee
- Kyung Hee University, Seoul, Republic of Korea
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Kolari P, Chan T, Porcar-Castell A, Bäck J, Nikinmaa E, Juurola E. Field and controlled environment measurements show strong seasonal acclimation in photosynthesis and respiration potential in boreal Scots pine. FRONTIERS IN PLANT SCIENCE 2014; 5:717. [PMID: 25566291 PMCID: PMC4264410 DOI: 10.3389/fpls.2014.00717] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2014] [Accepted: 11/28/2014] [Indexed: 05/26/2023]
Abstract
Understanding the seasonality of photosynthesis in boreal evergreen trees and its control by the environment requires separation of the instantaneous and slow responses, as well as the dynamics of light reactions, carbon reactions, and respiration. We determined the seasonality of photosynthetic light response and respiration parameters of Scots pine (Pinus sylvestris L.) in the field in southern Finland and in controlled laboratory conditions. CO2 exchange and chlorophyll fluorescence were measured in the field using a continuously operated automated chamber setup and fluorescence monitoring systems. We also carried out monthly measurements of photosynthetic light, CO2 and temperature responses in standard conditions with a portable IRGA and fluorometer instrument. The field and response measurements indicated strong seasonal variability in the state of the photosynthetic machinery with a deep downregulation during winter. Despite the downregulation, the photosynthetic machinery retained a significant capacity during winter, which was not visible in the field measurements. Light-saturated photosynthesis (P sat) and the initial slope of the photosynthetic light response (α) obtained in standard conditions were up to 20% of their respective summertime values. Respiration also showed seasonal acclimation with peak values of respiration in standard temperature in spring and decline in autumn. Spring recovery of all photosynthetic parameters could be predicted with temperature history. On the other hand, the operating quantum yield of photosystem II and the initial slope of photosynthetic light response stayed almost at the summertime level until late autumn while at the same time P sat decreased following the prevailing temperature. Comparison of photosynthetic parameters with the environmental drivers suggests that light and minimum temperature are also decisive factors in the seasonal acclimation of photosynthesis in boreal evergreen trees.
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Affiliation(s)
- Pasi Kolari
- Department of Physics, University of HelsinkiHelsinki, Finland
| | - Tommy Chan
- Department of Forest Sciences, University of HelsinkiHelsinki, Finland
| | | | - Jaana Bäck
- Department of Forest Sciences, University of HelsinkiHelsinki, Finland
| | - Eero Nikinmaa
- Department of Forest Sciences, University of HelsinkiHelsinki, Finland
| | - Eija Juurola
- Department of Physics, University of HelsinkiHelsinki, Finland
- Department of Forest Sciences, University of HelsinkiHelsinki, Finland
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Kasurinen V, Alfredsen K, Kolari P, Mammarella I, Alekseychik P, Rinne J, Vesala T, Bernier P, Boike J, Langer M, Belelli Marchesini L, van Huissteden K, Dolman H, Sachs T, Ohta T, Varlagin A, Rocha A, Arain A, Oechel W, Lund M, Grelle A, Lindroth A, Black A, Aurela M, Laurila T, Lohila A, Berninger F. Latent heat exchange in the boreal and arctic biomes. GLOBAL CHANGE BIOLOGY 2014; 20:3439-3456. [PMID: 24889888 DOI: 10.1111/gcb.12640] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2014] [Accepted: 03/13/2014] [Indexed: 06/03/2023]
Abstract
In this study latent heat flux (λE) measurements made at 65 boreal and arctic eddy-covariance (EC) sites were analyses by using the Penman-Monteith equation. Sites were stratified into nine different ecosystem types: harvested and burnt forest areas, pine forests, spruce or fir forests, Douglas-fir forests, broadleaf deciduous forests, larch forests, wetlands, tundra and natural grasslands. The Penman-Monteith equation was calibrated with variable surface resistances against half-hourly eddy-covariance data and clear differences between ecosystem types were observed. Based on the modeled behavior of surface and aerodynamic resistances, surface resistance tightly control λE in most mature forests, while it had less importance in ecosystems having shorter vegetation like young or recently harvested forests, grasslands, wetlands and tundra. The parameters of the Penman-Monteith equation were clearly different for winter and summer conditions, indicating that phenological effects on surface resistance are important. We also compared the simulated λE of different ecosystem types under meteorological conditions at one site. Values of λE varied between 15% and 38% of the net radiation in the simulations with mean ecosystem parameters. In general, the simulations suggest that λE is higher from forested ecosystems than from grasslands, wetlands or tundra-type ecosystems. Forests showed usually a tighter stomatal control of λE as indicated by a pronounced sensitivity of surface resistance to atmospheric vapor pressure deficit. Nevertheless, the surface resistance of forests was lower than for open vegetation types including wetlands. Tundra and wetlands had higher surface resistances, which were less sensitive to vapor pressure deficits. The results indicate that the variation in surface resistance within and between different vegetation types might play a significant role in energy exchange between terrestrial ecosystems and atmosphere. These results suggest the need to take into account vegetation type and phenology in energy exchange modeling.
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Affiliation(s)
- Ville Kasurinen
- Department of Forest Sciences, University of Helsinki, POBox 27, Helsinki, 00014, Finland; Department of Hydraulic and Environmental Engineering, Norwegian University of Science and Technology, Trondheim, Norway
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Lintunen A, Hölttä T, Kulmala M. Anatomical regulation of ice nucleation and cavitation helps trees to survive freezing and drought stress. Sci Rep 2014; 3:2031. [PMID: 23778457 PMCID: PMC3686780 DOI: 10.1038/srep02031] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2013] [Accepted: 05/31/2013] [Indexed: 11/25/2022] Open
Abstract
Water in the xylem, the water transport system of plants, is vulnerable to freezing and cavitation, i.e. to phase change from liquid to ice or gaseous phase. The former is a threat in cold and the latter in dry environmental conditions. Here we show that a small xylem conduit diameter, which has previously been shown to be associated with lower cavitation pressure thus making a plant more drought resistant, is also associated with a decrease in the temperature required for ice nucleation in the xylem. Thus the susceptibility of freezing and cavitation are linked together in the xylem of plants. We explain this linkage by the regulation of the sizes of the nuclei catalysing freezing and drought cavitation. Our results offer better understanding of the similarities of adaption of plants to cold and drought stress, and offer new insights into the ability of plants to adapt to the changing environment.
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Affiliation(s)
- A Lintunen
- Department of Forest Sciences, University of Helsinki, Helsinki, Finland.
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Wallin G, Hall M, Slaney M, Räntfors M, Medhurst J, Linder S. Spring photosynthetic recovery of boreal Norway spruce under conditions of elevated [CO(2)] and air temperature. TREE PHYSIOLOGY 2013; 33:1177-1191. [PMID: 24169104 DOI: 10.1093/treephys/tpt066] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Accumulated carbon uptake, apparent quantum yield (AQY) and light-saturated net CO2 assimilation (Asat) were used to assess the responses of photosynthesis to environmental conditions during spring for three consecutive years. Whole-tree chambers were used to expose 40-year-old field-grown Norway spruce trees in northern Sweden to an elevated atmospheric CO2 concentration, [CO2], of 700 μmol CO2 mol(-1) (CE) and an air temperature (T) between 2.8 and 5.6 °C above ambient T (TE), during summer and winter. Net shoot CO2 exchange (Anet) was measured continuously on 1-year-old shoots and was used to calculate the accumulated carbon uptake and daily Asat and AQY. The accumulated carbon uptake, from 1 March to 30 June, was stimulated by 33, 44 and 61% when trees were exposed to CE, TE, and CE and TE combined, respectively. Air temperature strongly influenced the timing and extent of photosynthetic recovery expressed as AQY and Asat during the spring. Under elevated T (TE), the recovery of AQY and Asat commenced ∼10 days earlier and the activity of these parameters was significantly higher throughout the recovery period. In the absence of frost events, the photosynthetic recovery period was less than a week. However, frost events during spring slowed recovery so that full recovery could take up to 60 days to complete. Elevated [CO2] stimulated AQY and Asat on average by ∼10 and ∼50%, respectively, throughout the recovery period, but had minimal or no effect on the onset and length of the photosynthetic recovery period during the spring. However, AQY, Asat and Anet all recovered at significantly higher T (average +2.2 °C) in TE than in TA, possibly caused by acclimation or by shorter days and lower light levels during the early part of the recovery in TE compared with TA. The results suggest that predicted future climate changes will cause prominent stimulation of photosynthetic CO2 uptake in boreal Norway spruce forest during spring, mainly caused by elevated T, but also elevated [CO2]. However, the effects of elevated T may not be linearly extrapolated to future warmer climates.
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Affiliation(s)
- Göran Wallin
- Department of Biological and Environmental Sciences, University of Gothenburg, PO Box 461, SE-405 30 Göteborg, Sweden
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31
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Wu J, Guan D, Yuan F, Wang A, Jin C. Soil temperature triggers the onset of photosynthesis in Korean pine. PLoS One 2013; 8:e65401. [PMID: 23755227 PMCID: PMC3670906 DOI: 10.1371/journal.pone.0065401] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2012] [Accepted: 04/25/2013] [Indexed: 11/19/2022] Open
Abstract
In forest ecosystems, the onset of spring photosynthesis may have an important influence on the annual carbon balance. However, triggers for the onset of photosynthesis have yet to be clearly identified, especially for temperate evergreen conifers. The effects of climatic factors on recovery of photosynthetic capacity in a Korean pine forest were investigated in the field. No photosynthesis was detectable when the soil temperature was below 0 °C even if the air temperature was far beyond 15 °C. The onset of photosynthesis and sap flow was coincident with the time of soil thawing. The rates of recovery of photosynthetic capacity highly fluctuated with air temperature after onset of photosynthesis, and intermittent frost events remarkably inhibited the photosynthetic capacity of the needles. The results suggest that earlier soil thawing is more important than air temperature increases in triggering the onset of photosynthesis in Korean pine in temperate zones under global warming scenarios.
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Affiliation(s)
- Jiabing Wu
- State Key Laboratory of Forest and Soil Ecology, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang, P.R. China
| | - Dexin Guan
- State Key Laboratory of Forest and Soil Ecology, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang, P.R. China
| | - Fenhui Yuan
- State Key Laboratory of Forest and Soil Ecology, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang, P.R. China
| | - Anzhi Wang
- State Key Laboratory of Forest and Soil Ecology, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang, P.R. China
| | - Changjie Jin
- State Key Laboratory of Forest and Soil Ecology, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang, P.R. China
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Koo KA, Patten BC, Teskey RO. Assessing environmental factors in red spruce (Picea rubens Sarg.) growth in the Great Smoky Mountains National Park, USA: From conceptual model, envirogram, to simulation model. Ecol Modell 2011. [DOI: 10.1016/j.ecolmodel.2010.11.020] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Hall M, Räntfors M, Slaney M, Linder S, Wallin G. Carbon dioxide exchange of buds and developing shoots of boreal Norway spruce exposed to elevated or ambient CO2 concentration and temperature in whole-tree chambers. TREE PHYSIOLOGY 2009; 29:467-81. [PMID: 19203983 DOI: 10.1093/treephys/tpn047] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Effects of ambient and elevated temperature and atmospheric carbon dioxide concentration ([CO2]) on CO2 assimilation rate and the structural and phenological development of shoots during their first growing season were studied in 45-year-old Norway spruce trees (Picea abies (L.) Karst.) enclosed in whole-tree chambers. Continuous measurements of net assimilation rate (NAR) in individual buds and shoots were made from early bud development to late August in two consecutive years. The largest effect of elevated temperature (TE) was manifest early in the season as an earlier start and completion of shoot length development, and a 1-3-week earlier shift from negative to positive NAR compared with the ambient temperature (TA) treatments. The largest effect of elevated [CO2] (CE) was found later in the season, with a 30% increase in maximum NAR compared with trees in the ambient [CO2] treatments (CA), and shoots assimilating their own mass in terms of carbon earlier in the CE treatments than in the CA treatments. Once the net carbon assimilation compensation point (NACP) had been reached, TE had little or no effect on the development of NAR performance, whereas CE had little effect before the NACP. No interactive effects of TE and CE on NAR were found. We conclude that in a climate predicted for northern Sweden in 2100, current-year shoots of P. abies will assimilate their own mass in terms of carbon 20-30 days earlier compared with the current climate, and thereby significantly contribute to canopy assimilation during their first year.
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Affiliation(s)
- Marianne Hall
- Department of Plant and Environmental Sciences, University of Gothenburg, P.O. Box 461, SE-405 30 Göteborg, Sweden.
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Rutter N, Essery R, Pomeroy J, Altimir N, Andreadis K, Baker I, Barr A, Bartlett P, Boone A, Deng H, Douville H, Dutra E, Elder K, Ellis C, Feng X, Gelfan A, Goodbody A, Gusev Y, Gustafsson D, Hellström R, Hirabayashi Y, Hirota T, Jonas T, Koren V, Kuragina A, Lettenmaier D, Li WP, Luce C, Martin E, Nasonova O, Pumpanen J, Pyles RD, Samuelsson P, Sandells M, Schädler G, Shmakin A, Smirnova TG, Stähli M, Stöckli R, Strasser U, Su H, Suzuki K, Takata K, Tanaka K, Thompson E, Vesala T, Viterbo P, Wiltshire A, Xia K, Xue Y, Yamazaki T. Evaluation of forest snow processes models (SnowMIP2). ACTA ACUST UNITED AC 2009. [DOI: 10.1029/2008jd011063] [Citation(s) in RCA: 255] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Krishnan P, Black TA, Barr AG, Grant NJ, Gaumont-Guay D, Nesic Z. Factors controlling the interannual variability in the carbon balance of a southern boreal black spruce forest. ACTA ACUST UNITED AC 2008. [DOI: 10.1029/2007jd008965] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Ensminger I, Schmidt L, Lloyd J. Soil temperature and intermittent frost modulate the rate of recovery of photosynthesis in Scots pine under simulated spring conditions. THE NEW PHYTOLOGIST 2008; 177:428-442. [PMID: 18181961 DOI: 10.1111/j.1469-8137.2007.02273.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
An earlier onset of photosynthesis in spring for boreal forest trees is predicted as the climate warms, yet the importance of soil vs air temperatures for spring recovery remains to be determined. Effects of various soil- and air-temperature conditions on spring recovery of photosynthesis in Scots pine (Pinus sylvestris) seedlings were assessed under controlled environmental conditions. Using winter-acclimated seedlings, photosynthetic responses were followed after transfer to different simulated spring conditions. Recovery rates for photosynthetic electron transport and net CO(2) uptake were slower in plants from cold or frozen soil compared with controls. In addition, a greater fraction of light absorbed was not used photochemically, but was dissipated thermally via xanthophyll cycle pigments. Intermittent frost events decreased photosynthetic capacity and increased thermal energy dissipation. Within a few days after frost events, photosynthetic capacity recovered to prefrost levels. After 18 d under spring conditions, no difference in the optimum quantum yield of photosynthesis was observed between seedlings that had been exposed to intermittent frost and control plants. These results show that, if air temperatures remain favourable and spells of subfreezing air temperatures are only of short duration, intermittent frost events delay but do not severely inhibit photosynthetic recovery in evergreen conifers during spring. Cold and/or frozen soils exert much stronger inhibitory effects on the recovery process, but they do not totally inhibit it.
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Affiliation(s)
- Ingo Ensminger
- Max-Planck-Institut für Biogeochemie, Hans-Knöll-Straße 10, 07745 Jena, Germany
- Present address: Max-Planck-Institut für Molekulare Pflanzenphysiologie, Am Mühlenberg 1, 14476 Golm, Germany and Institut für Forstbotanik und Baumphysiologie, Universität Freiburg, 79110 Freiburg, Germany
| | - Lilian Schmidt
- Max-Planck-Institut für Biogeochemie, Hans-Knöll-Straße 10, 07745 Jena, Germany
| | - Jon Lloyd
- Earth and Biosphere Institute, School of Geography, University of Leeds, Leeds LS2 9JT, UK
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