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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Gold perfusion experiments support the multi‐layered, mesoporous nature of intervessel pit membranes in angiosperm xylem

New Phytologist, Journal Year: 2024, Volume and Issue: 242(2), P. 493 - 506

Published: Feb. 25, 2024

Fluid transport across intervessel pit membranes of angiosperm xylem plays a major role in plant transpiration, with resistance largely depending on pore constriction sizes. Traditionally, fluid particles traversing are assumed to cross single instead multiple constrictions. We tested multi-layered membrane model eight species by estimating the size frequency constrictions relation thickness and compared modelled data perfusion characteristics nanoscale gold based transmission electron microscopy. The showed similar patterns measured number perfused particle sizes inside membranes, although values were 10-50 times below data. Small enter most easily, especially when injected thin membranes. trapping becomes more likely increasing thickness. While quantitative differences between experimental due various practical limitations, their qualitative agreement supports Pore 5 50 nm realistic, confirm mesoporous nature

Language: Английский

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Rootstocks affect the vulnerability to embolism and pit membrane thickness in Citrus scions

Plant Cell & Environment, Journal Year: 2024, Volume and Issue: 47(8), P. 3063 - 3075

Published: April 25, 2024

Abstract Embolism resistance of xylem tissue varies among species and is an important trait related to drought resistance, with anatomical attributes like pit membrane thickness playing role in avoiding embolism spread. Grafted Citrus trees are commonly grown orchards, the rootstock being able affect whole plant. Here, we evaluated how rootstocks vulnerability scion using several rootstock/scion combinations. Scions ‘Tahiti’ acid lime, ‘Hamlin’, ‘Pera’ ‘Valencia’ oranges grafted on a ‘Rangpur’ lime exhibit similar embolism. In field‐grown trees, measurements leaf water potential did not suggest significant formation during dry season, while stomata presented isohydric response declining availability. When orange scions were ‘IAC 1710’ citrandarin, ‘Sunki Tropical’ mandarin or ‘Swingle’ citrumelo rootstocks, variation intervessel was found. The rootstock, which known for its induced thicker membranes scion, resulting higher than other rootstocks. Similarly, citrandarin generated increased highly relevant citriculture.

Language: Английский

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The relative area of vessels in xylem correlates with stem embolism resistance within and between genera

Tree Physiology, Journal Year: 2022, Volume and Issue: 43(1), P. 75 - 87

Published: Sept. 7, 2022

The resistance of xylem conduits to embolism is a major factor defining drought tolerance and can set the distributional limits species across rainfall gradients. Recent work suggests that proximity vessels neighbors increases vulnerability conduit. We therefore investigated whether relative vessel area correlates with intra- inter-generic variation in pairs or triplets from genera Acer, Cinnamomum, Ilex, Quercus Persea, adapted environments differing aridity. used optical method assess stems conducted anatomical measurements on which was quantified. Vessel lumen fraction (VLF) correlated within genera. A low VLF likely gas movement between conduits, by diffusion advection, whereas high enhances transport thorough increased conduit-to-conduit connectivity reduced distances likelihood propagation. suggest rate due local pressure differences network central driver propagation angiosperm vessels.

Language: Английский

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Divergence of hydraulic traits among tropical forest trees across topographic and vertical environment gradients in Borneo

New Phytologist, Journal Year: 2022, Volume and Issue: 235(6), P. 2183 - 2198

Published: May 28, 2022

Summary Fine‐scale topographic–edaphic gradients are common in tropical forests and drive species spatial turnover marked changes forest structure function. We evaluate how hydraulic traits of tree relate to vertical horizontal niche specialization along such a gradient. Along gradient with uniform climate Borneo, we measured six key 156 individuals differing heights 13 Dipterocarpaceae. investigated habitat, height their interaction on this Embolism resistance increased trees sandy soils but did not vary height. By contrast, water transport capacity sandier increasing Habitat only interact for efficiency, slope changing from positive negative the clay‐rich soil. type influenced trait–trait relationships all except wood density. Our data reveal that variation dipterocarps is driven by combination conditions, taxonomic identity. work indicates play significant role shaping across may contribute among dipterocarp species.

Language: Английский

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Angiosperms follow a convex trade‐off to optimize hydraulic safety and efficiency

New Phytologist, Journal Year: 2023, Volume and Issue: 240(5), P. 1788 - 1801

Published: Sept. 10, 2023

Intervessel pits are considered to function as valves that avoid embolism spreading and optimize efficient transport of xylem sap across neighbouring vessels. Hydraulic between vessels would therefore follow a safety-efficiency trade-off, which is directly related the total intervessel pit area (Ap ), inversely membrane thickness (TPM ) driven by pressure difference. To test this hypothesis, we modelled relative rate gas (ka water (Q) at level for 23 angiosperm species correlated these parameters with potential 50% occurs (Ψ50 ). We also measured ka 10 using pneumatic measurements. The difference adjacent estimated values Q were Ψ50 , following convex trade-off based on experimental data. Minor changes in TPM Ap exponentially affected flow, respectively. Our results provide clear evidence not linear, but due flow membranes, represent mesoporous media within microporous conduits. Moreover, nature long-distance may contribute an adjustable fluid balance plants, depending environmental conditions.

Language: Английский

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Gas diffusion kinetics in relation to embolism formation and propagation in angiosperm xylem: a mini-review

Acta Horticulturae, Journal Year: 2025, Volume and Issue: 1419, P. 123 - 134

Published: Feb. 1, 2025

Language: Английский

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Assessing the agreement between the pneumatic and the flow‐centrifuge method for estimating xylem safety in temperate diffuse‐porous tree species

Plant Biology, Journal Year: 2023, Volume and Issue: 25(7), P. 1171 - 1185

Published: Sept. 13, 2023

The increasing frequency of global change-type droughts has created a need for fast, accurate and widely applicable techniques estimating xylem embolism resistance to improve forecasts future forest changes. We used data from 12 diffuse-porous temperate tree species covering wide range safety compare the pneumatic flow-centrifuge method, two rapid methods constructing vulnerability curves. evaluated agreement between parameters estimated with both sensitivity measurements duration air discharge (AD) measurements. There was close water potentials at 50% discharged (PAD), Pneumatron, loss hydraulic conductivity (PLC), method (mean signed deviation: 0.12 MPa, Pearson correlation: 0.96 after 15 s gas extraction). However, relationship slopes more variable, resulting in lower potential 12% 88% PAD/PLC. not affected by species-specific vessel length distributions. All were sensitive AD time. Overall highest relatively short times, an optimum 16 s. Our results highlight value Pneumatron as easy reliable tool estimate thresholds angiosperms. Further, our study provides set useful metrics methodological comparisons curves terms systematic random deviations, well overall agreement.

Language: Английский

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A User Manual to Measure Gas Diffusion Kinetics in Plants: Pneumatron Construction, Operation, and Data Analysis

Frontiers in Plant Science, Journal Year: 2021, Volume and Issue: 12

Published: June 7, 2021

The Pneumatron device measures gas diffusion kinetics in the xylem of plants. provides an easy, low-cost, and powerful tool for research on plant water relations exchange. Here, we describe detail how to construct operate this estimate embolism resistance angiosperm xylem, analyse pneumatic data. Simple more elaborated ways constructing a are shown, either using wires, breadboard, or printed circuit board. instrument is based open-source hardware software system, which allows users it automated semi-automated way. A step-by-step manual troubleshooting section provided. An excel spreadsheet R-script also presented fast easy data analysis. This aims at helping avoid common mistakes, such as unstable measurements minimum maximum amount discharged from tissue, has major consequences estimating resistance. Major advantages include its accurate rates, including highly precise volume intact, embolised conduits. It currently unclear if method can be applied woody monocots, gymnosperm species that possess torus-margo pit membranes, herbaceous species.

Language: Английский

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The potential link between gas diffusion and embolism spread in angiosperm xylem: Evidence from flow‐centrifuge experiments and modelling

Plant Cell & Environment, Journal Year: 2024, Volume and Issue: 47(12), P. 4977 - 4991

Published: Aug. 9, 2024

Abstract Understanding xylem embolism formation is challenging due to dynamic changes and multiphase interactions in conduits. Here, we hypothesise that spread involves gas diffusion xylem, affected by time. We measured hydraulic conductivity (K h ) flow‐centrifuge experiments over 1 at a given pressure temperature for stem samples of three angiosperm species. Temporal K 5, 22, 35°C, various pressures were compared modelled concentration recently embolised vessel the centre centrifuge sample. logarithmic species‐specific. Maximum relative increases between 6% 40% happened 22°C low centrifugal speed (<3250 RPM), while maximum decreases 41% 61% occurred higher speeds. These reductions experimentally shown be associated with temporal increase samples, which was likely embolized vessels. Although mostly pressure‐driven, our experimental data indicate time, conduit characteristics, are involved their potential role diffusion. Gas diffusion, however, does not seem cover entire process spread.

Language: Английский

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