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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Hydraulic prediction of drought‐induced plant dieback and top‐kill depends on leaf habit and growth form

Ecology Letters, Journal Year: 2021, Volume and Issue: 24(11), P. 2350 - 2363

Published: Aug. 18, 2021

Abstract Hydraulic failure caused by severe drought contributes to aboveground dieback and whole‐plant death. The extent which or death can be predicted plant hydraulic traits has rarely been tested among species with different leaf habits and/or growth forms. We investigated 19 in 40 woody a tropical savanna their potential correlations response during an extreme event the El Niño–Southern Oscillation 2015. Plant trait variation was partitioned substantially habit but not form along trade‐off axis between that support tolerance versus avoidance. Semi‐deciduous shrubs had highest branch top‐kill (complete death) Dieback were well explained combining form, suggesting integrating life history will yield better predictions.

Language: Английский

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Unlocking Drought-Induced Tree Mortality: Physiological Mechanisms to Modeling

Frontiers in Plant Science, Journal Year: 2022, Volume and Issue: 13

Published: April 4, 2022

Drought-related tree mortality has become a major concern worldwide due to its pronounced negative impacts on the functioning and sustainability of forest ecosystems. However, our ability identify species that are most vulnerable drought, pinpoint spatial temporal patterns events, is still limited. Model useful tools capture dynamics vegetation at spatiotemporal scales, yet contemporary land surface models (LSMs) often incapable predicting response environmental perturbations with sufficient accuracy, especially under stressful conditions such as drought. Significant progress been made regarding physiological mechanisms underpinning plant drought in past decade, hydraulic dysfunction emerged key determinant for death water shortage. The identification pivotal events relevant traits may facilitate forecasting through mechanistic approach, improved precision. In this review, we (1) summarize current understanding leading death, (2) describe functionality involved process dysfunction, (3) outline their roles improving representation function LSMs. We urge potential future research detailed processes pinpointing corresponding functional traits, well variation across within species, better drought-induced models.

Language: Английский

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Hydraulic determinants of drought-induced tree mortality and changes in tree abundance between two tropical forests with different water availability

Agricultural and Forest Meteorology, Journal Year: 2023, Volume and Issue: 331, P. 109329 - 109329

Published: Jan. 28, 2023

Language: Английский

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Divergent leaf and fine root “pressure–volume relationships” across habitats with varying water availability

PLANT PHYSIOLOGY, Journal Year: 2022, Volume and Issue: 190(4), P. 2246 - 2259

Published: Sept. 1, 2022

Fine roots and leaves, the direct interfaces of plants with their external environment along soil-plant-atmosphere continuum, are at front line to ensure plant adaptation growing habitat. This study aimed compare vulnerability water deficit fine leaves woody species from karst mangrove forests-two water-stressed habitats-against that timber ornamental grown in a well-watered common garden. Thus, pressure-volume curves both organs 37 (about 12 each habitat) were constructed. wilted less negative potential than 32 before branch xylem lost 50% its hydraulic conductivity 17 available data on embolism resistance. turgor loss can act as fuse mechanism against stress. Mangroves had higher leaf resistance wilting lower leaf-specific area garden plants. Their high specific root lengths (SRL) capacitance buffer Karst bulk modulus, low capacitance, delayed wilting. showed general contribution protection whole underground Our findings highlight importance storage tolerance some species.

Language: Английский

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High vapour pressure deficit enhances turgor limitation of stem growth in an Asian tropical rainforest tree

Plant Cell & Environment, Journal Year: 2023, Volume and Issue: 46(9), P. 2747 - 2762

Published: July 10, 2023

Abstract Tropical forests are experiencing increases in vapour pressure deficit ( D ), with possible negative impacts on tree growth. Tree‐growth reduction due to rising is commonly attributed carbon limitation, thus overlooking the potentially important mechanism of D‐ induced impairment wood formation an increase turgor limitation. Here we calibrate a mechanistic tree‐growth model simulate limitation radial stem growth mature Toona cilitata trees Asian tropical forest. Hourly sap flow and dendrometer measurements were collected turgor‐driven during growing season. Simulated seasonal patterns matched well observations. Growth mainly occurred at night its pre‐dawn build‐up appeared be limited under higher . Across seasons, night‐time required for was negatively related previous midday , possibly relatively high canopy conductance relative rehydration. These findings provide first evidence that grow limits We suggest including models also forest dynamics, particular, if these effects warming increased frequency droughts.

Language: Английский

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A unit pipe pneumatic model to simulate gas kinetics during measurements of embolism in excised angiosperm xylem

Tree Physiology, Journal Year: 2022, Volume and Issue: 43(1), P. 88 - 101

Published: Sept. 1, 2022

Abstract The pneumatic method has been introduced to quantify embolism resistance in plant xylem of various organs by applying a partial vacuum cut-open xylem. Despite the similarity vulnerability curves between and other methods, modeling approach is needed investigate if changes during dehydration can be accurately quantified based on gas diffusion kinetics. Therefore, unit pipe (UPPn) model was developed estimate extraction from intact conduits, which were axially interconnected inter-conduit pit membranes conduits. physical laws used included Fick’s law for diffusion, Henry’s concentration partitioning liquid phases at equilibrium ideal law. UPPn showed that 91% extracted came first five series embolized, conduits only 9% aqueous phase after 15 s simulation. Considering alternative sources, measured with pneumatron device systematically overestimated 2–17%, corresponded typical measuring error 0.11 MPa P50 (the water potential equivalent 50% maximum amount extracted). It concluded directly measure due fast movement across interconduit membranes, while sap hydrated cell walls about 100 times slower. We expect will also contribute understanding propagation temporal dynamics.

Language: Английский

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Xylem conduit deformation across vascular plants: an evolutionary spandrel or protective valve?

New Phytologist, Journal Year: 2022, Volume and Issue: 237(4), P. 1242 - 1255

Published: Oct. 29, 2022

The hydraulic system of vascular plants and its integrity is essential for plant survival. To transport water under tension, the walls xylem conduits must approximate rigid pipes. Against this expectation, conduit deformation has been reported in leaves a few species hypothesized to function as 'circuit breaker' against embolism. Experimental evidence lacking, generality unknown. We demonstrated role protecting upstream from embolism through experiments on three surveyed diverse selection leaves. Conduit minor veins occurred before during slow dehydration. When were exposed transient increases transpiration, was accompanied by large potential differences leaf stem minimal xylem. In tested, collapsible vein endings provided clear protection transpiration. found plants, including 11 eudicots, ginkgo, cycad, fern, bamboo, grass species, but not two bamboo palm demonstrating that functionality may be widespread across plants.

Language: Английский

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A low‐cost protocol for the optical method of vulnerability curves to calculate P₅₀

Applications in Plant Sciences, Journal Year: 2025, Volume and Issue: unknown

Published: March 31, 2025

The quantification of plant drought resistance, particularly embolism formation, within and across species, is critical for ecosystem management agriculture. We developed a cost-effective protocol to measure the water potential at which 50% hydraulic conductivity (P 50) lost in stems, using affordable accessible materials comparison traditional optical method. Our uses inexpensive USB microscopes, are secured along with plants pegboard base avoid movement. A Python program automatized image acquisition. This method was applied quantify P 50 an exotic species (Nicotiana glauca) native (Rhus integrifolia) Mediterranean vegetation Baja California, Mexico. intra- interspecific patterns variation stem N. glauca R. integrifolia were obtained low-cost widely available that can be easily replicated other species.

Language: Английский

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Response of four evergreen savanna shrubs to an incidence of extreme drought: high embolism resistance, branch shedding and maintenance of nonstructural carbohydrates

Tree Physiology, Journal Year: 2021, Volume and Issue: 42(4), P. 740 - 753

Published: Nov. 20, 2021

Abstract Extreme drought events are becoming frequent globally, resulting in widespread plant mortality and forest dieback. Although savanna vegetation cover ~20% of the earth’s land area, their responses to extreme have been less studied than that forests. Herein, we quantified branch dieback, individual associated physiological four evergreen shrubs (Tarenna depauperate Hutch., Maytenus esquirolii (H. Lév.) C.Y. Cheng, Murraya exotica L., Jasminum nudiflorum Lindl.) a ecosystem Southwest China an incidence during 2019 2020. We found 80–100% individuals these species exhibited whereas was only T. (4.5%). All showed high resistance stem embolism (P50, water potential at 50% loss hydraulic conductivity ranged from −5.62 −8.6 MPa), minimum potentials reached −7.6 ca −10.0 MPa drought. The low caused native levels (percentage (PLC) 23–65%) terminal branches, remaining stems maintained 15–35% PLC end Large within-individual variations vulnerability were detected, shedding vulnerable branches could be mechanism for reduce carbon consumption. Overall, content total nonstructural carbohydrates (NSC) components generally comparable or higher those rainy season three species. Because leaves turgor-less most time drought, NSC due recycling dead translocation roots. Our results suggest tolerance shrub which facilitated by some maintain balance.

Language: Английский

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