Basin-wide variation in tree hydraulic safety margins predicts the carbon balance of Amazon forests

Nature, Journal Year: 2023, Volume and Issue: 617(7959), P. 111 - 117

Published: April 26, 2023

Abstract Tropical forests face increasing climate risk 1,2 , yet our ability to predict their response change is limited by poor understanding of resistance water stress. Although xylem embolism thresholds (for example, $$\varPsi $$ Ψ 50 ) and hydraulic safety margins HSM are important predictors drought-induced mortality 3–5 little known about how these vary across Earth’s largest tropical forest. Here, we present a pan-Amazon, fully standardized traits dataset use it assess regional variation in drought sensitivity trait species distributions long-term forest biomass accumulation. Parameters markedly the Amazon related average rainfall characteristics. Both influence biogeographical distribution tree species. However, was only significant predictor observed decadal-scale changes biomass. Old-growth with wide gaining more than low forests. We propose that this may be associated growth–mortality trade-off whereby trees consisting fast-growing take greater risks risk. Moreover, regions pronounced climatic change, find evidence losing biomass, suggesting operating beyond limits. Continued likely further reduce 6,7 strong implications for carbon sink.

Language: Английский

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Small and slow is safe: On the drought tolerance of tropical tree species

Global Change Biology, Journal Year: 2022, Volume and Issue: 28(8), P. 2622 - 2638

Published: Jan. 10, 2022

Understanding how evolutionary history and the coordination between trait trade-off axes shape drought tolerance of trees is crucial to predict forest dynamics under climate change. Here, we compiled traits related fast-slow stature-recruitment in 601 tropical woody species explore their covariations phylogenetic signals. We found that xylem resistance embolism (P50) determines risk hydraulic failure, while functional significance leaf turgor loss point (TLP) relies on its with water use strategies. P50 TLP exhibit weak signals substantial variation within genera. closely associated axis: slow maintain functioning higher stress. both axes: small more resistant xylem. Lower phosphorus concentration xylem, which suggests a (nutrient drought) stress-tolerance syndrome tropics. Overall, our results imply (1) strong selective pressure forests, result from repeated adaptation taxa, (2) coordinated ecological strategies governing demography. These findings provide physiological basis interpret drought-induced shift toward slow-growing, smaller, denser-wooded observed tropics, implications for restoration programmes.

Language: Английский

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High heat tolerance, evaporative cooling, and stomatal decoupling regulate canopy temperature and their safety margins in three European oak species

Global Change Biology, Journal Year: 2024, Volume and Issue: 30(8)

Published: Aug. 1, 2024

Abstract Heatwaves and soil droughts are increasing in frequency intensity, leading many tree species to exceed their thermal thresholds, driving wide‐scale forest mortality. Therefore, investigating heat tolerance canopy temperature regulation mechanisms is essential understanding predicting vulnerability hot droughts. We measured the diurnal seasonal variation leaf water potential (Ψ), gas exchange (photosynthesis A net stomatal conductance g s ), ( T can (leaf critical crit safety margins TSM, i.e., difference between maximum ) three oak forests along a latitudinal gradient Quercus petraea Switzerland, ilex France, coccifera Spain) throughout growing season. Gas Ψ of all were strongly reduced by increased air drying, resulting closure inhibition photosynthesis Q. when surpassed 30°C moisture dropped below 14%. Across seasons, was mainly above but (up 10°C > null or negative. Although trees endured extreme 42°C), positive TSM maintained during season due high (average 54.7°C) possibly decoupling (i.e., ≤0 while >0). Indeed, low (despite decreasing passed embolism thresholds. This may have prevented from rising heat. Overall, our work highlighted that behind include combination evaporative cooling, large limits, decoupling. These processes must be considered accurately predict plant damages, survival, mortality heatwaves.

Language: Английский

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SurEau-Ecos v2.0: a trait-based plant hydraulics model for simulations of plant water status and drought-induced mortality at the ecosystem level

Geoscientific model development, Journal Year: 2022, Volume and Issue: 15(14), P. 5593 - 5626

Published: July 21, 2022

Abstract. A widespread increase in tree mortality has been observed around the globe, and this trend is likely to continue because of ongoing climate-induced increases drought frequency intensity. This raises need identify regions ecosystems that are experience most frequent significant damage. We present SurEau-Ecos, a trait-based, plant hydraulic model designed predict desiccation at scales from stand region. SurEau-Ecos draws on general principles SurEau but introduces simplified representation architecture alternative numerical schemes. Both additions were made facilitate parameterization large-scale applications. In water fluxes soil atmosphere represented through two organs (a leaf stem, which includes volume trunk, roots branches) as product an interface conductance difference between potentials. Each organ described by its symplasmic apoplasmic compartments. The dynamics plant's status beyond point stomatal closure explicitly via residual transpiration flow, cavitation solicitation plants' reservoirs. addition “explicit” scheme SurEau, we implemented “semi-implicit” “implicit” scheme. schemes led substantial gain computing time compared explicit (>10 000 times), implicit was accurate. also similar slight disparities infra-daily variations potentials, attributed differences models. global model's sensitivity analysis revealed factors controlling rates differ depending whether potential below or above closure. Total available for plant, area index 50 % mostly drove needed reach Once stomata closed, resistance cavitation, cuticular stocks determined failure. Finally, illustrated simulate regional drought-induced over France. promising tool perform regional-scale predictions failure, determine vulnerable areas drying conditions, assess forest flammability.

Language: Английский

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Drought acclimation of Quercus ilex leaves improves tolerance to moderate drought but not resistance to severe water stress

Plant Cell & Environment, Journal Year: 2022, Volume and Issue: 45(7), P. 1967 - 1984

Published: April 8, 2022

Increasing temperature and drought can result in leaf dehydration defoliation even drought-adapted tree species such as the Mediterranean evergreen Quercus ilex L. The stomatal regulation of water potential plays a central role avoiding this phenomenon is constrained by suite traits including hydraulic conductance vulnerability, capacitance, minimum to vapour, osmotic cell wall elasticity. We investigated whether plasticity these may improve tolerance two long-term rainfall exclusion experiments forests. Osmotic adjustment was observed lower at turgor loss rainfall-exclusion treatments, thus suggesting closure more negative potentials anisohydric behaviour drier conditions. Conversely, vulnerability did not exhibit any between treatments so safety margins were narrower treatments. sequence responses seasonal conserved among sites but trees likely suffer losses functioning conclude that might help tolerate moderate resist severe stress.

Language: Английский

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Xylem embolism spread is largely prevented by interconduit pit membranes until the majority of conduits are gas‐filled

Plant Cell & Environment, Journal Year: 2022, Volume and Issue: 45(4), P. 1204 - 1215

Published: Jan. 5, 2022

Xylem embolism resistance varies across species influencing drought tolerance, yet little is known about the determinants of an individual conduit. Here we conducted experiment using optical vulnerability method to test whether conduits have a specific water potential threshold for formation and pre-existing in neighbouring alters this threshold. Observations were made on diverse sample angiosperm conifer through cycle dehydration, rehydration subsequent dehydration death. Upon after embolism, no refilling was observed. When present, xylem had conserved, embolism-resistance that varied population conduits. The consequence variable conduit-specific small degree results apparently more resistant dehydrations, particularly angiosperms with vessels. While our suggest pit membranes separating are critical maintaining conserved conduit when as percentage embolized increases, gas movement, local pressure differences connectivity between increasingly contribute spread.

Language: Английский

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High Potassium Supply Detrimentally affects Nutrient use Efficiency and Photochemistry in Pinus spp. Seedlings

Journal of soil science and plant nutrition, Journal Year: 2025, Volume and Issue: unknown

Published: Feb. 14, 2025

Language: Английский

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Quantifying vulnerability to embolism in tropical trees and lianas using five methods: can discrepancies be explained by xylem structural traits?

New Phytologist, Journal Year: 2020, Volume and Issue: 229(2), P. 805 - 819

Published: Sept. 16, 2020

Summary Vulnerability curves (VCs) describe the loss of hydraulic conductance against increasing xylem tension, providing valuable insights about response plant water transport to stress. Techniques construct VCs have been developed and modified continuously, but controversies continue. We compared constructed using bench‐top dehydration (BD), air‐injection‐flow (AI), pneumatic‐air‐discharge (PAD), optical (OP) X‐ray‐computed microtomography (MicroCT) methods for tropical trees lianas with contrasting vessel lengths. The PAD method generated highly vulnerable VCs, AI intermediate whereas BD, OP MicroCT produced comparable more resistant VCs. Vessel‐length diameter accounted overestimation ratio vulnerability estimated not method. Compared directly measured midday embolism levels, substantially overestimated embolism, provided reasonable estimations. Cut‐open vessels, uncertainties in maximum air volume estimations, sample‐length effects, tissue cracks shrinkage together may impede reliability In conclusion, we validate plants, need further mechanistic testing. Therefore, applications estimating responses drought be cautious.

Language: Английский

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Stem and leaf xylem of angiosperm trees experiences minimal embolism in temperate forests during two consecutive summers with moderate drought

Plant Biology, Journal Year: 2022, Volume and Issue: 24(7), P. 1208 - 1223

Published: Jan. 6, 2022

Drought events may increase the likelihood that plant water transport system becomes interrupted by embolism. Yet our knowledge about temporal frequency of xylem embolism in field is frequently lacking, as it requires detailed, long-term measurements. We measured resistance and midday potentials during consecutive summers 2019 2020 to estimate maximum levels leaf stem ten temperate angiosperm tree species. also studied vessel pit membrane characteristics based on light electron microscopy corroborate potential differences between leaves stems. Apart from A. pseudoplatanus Q. petraea, eight species experienced minimum were close or below those required initiate Water corresponding ca. 12% loss hydraulic conductivity (PLC) could occur six species, while considerable around 50% PLC limited B. pendula C. avellana. There was a general agreement stems leaves, with being equally more resistant than Also, significantly correlated intervessel thickness (TPM ) for stems, but not diameter total surface area vessel. Our data indicate low amounts most moderate summer drought, are uncommon. Moreover, experimental TPM show generally no vulnerable xylem.

Language: Английский

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Divergent root water uptake depth and coordinated hydraulic traits among typical karst plantations of subtropical China: Implication for plant water adaptation under precipitation changes

Agricultural Water Management, Journal Year: 2021, Volume and Issue: 249, P. 106798 - 106798

Published: Feb. 21, 2021

Language: Английский

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