Deadly acceleration in dehydration of Eucalyptus viminalis leaves coincides with high-order vein cavitation

PLANT PHYSIOLOGY, Journal Year: 2023, Volume and Issue: 191(3), P. 1648 - 1661

Published: Jan. 24, 2023

Xylem cavitation during drought is proposed as a major driver of canopy collapse, but the mechanistic link between hydraulic failure and leaf damage in trees still uncertain. Here, we used tree species manna gum (Eucalyptus viminalis) to explore connection xylem dysfunction lethal desiccation leaves. Cavitation could theoretically trigger tissues by severing water supply under scenarios such runaway cavitation, or local terminal parts vein network. To investigate role death, compared timing photosynthetic machinery (Fv/Fm decline) with changes plant hydration imposed stress. The potential at which Fv/Fm was observed decline corresponded marking transition from slow very rapid tissue dehydration. Both events also occurred simultaneously initiation high-order veins (HOV, third order above) analytically derived point failure. close synchrony strongly points disruption for leaves this hardy evergreen tree. These results indicate that possibly triggered HOV network failure, tipping agent determining vulnerability E. viminalis suggest may play general plants.

Language: Английский

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Abscisic acid acts essentially on stomata, not on the xylem, to improve drought resistance in tomato

Plant Cell & Environment, Journal Year: 2023, Volume and Issue: 46(11), P. 3229 - 3241

Published: Aug. 1, 2023

Drought resistance is essential for plant production under water-limiting environments. Abscisic acid (ABA) plays a critical role in stomata but its impact on hydraulic function beyond the far less studied. We selected genotypes differing their ability to accumulate ABA investigate drought-induced dysfunction. All exhibited similar leaf and stem embolism regardless of differences levels. Their was also similar. Differences were only observed between two extreme genotypes: sitiens (sit; strong ABA-deficient mutant) sp12 (a transgenic line that constitutively overaccumulates ABA), where water potential inducing 50% 0.25 MPa lower than sit. Maximum stomatal minimum conductances considerably plants with higher (wild type [WT] sp12) mutants. Variations gas exchange across associated levels density size. The loss meant lethal potentials occurred later during drought plants, followed by WT, then Therefore, primary pathway which enhances via declines loss, delays dehydration

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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Extreme drought can deactivate ABA biosynthesis in embolism‐resistant species

Plant Cell & Environment, Journal Year: 2023, Volume and Issue: 47(2), P. 497 - 510

Published: Oct. 31, 2023

Abstract The phytohormone abscisic acid (ABA) is synthesised by plants during drought to close stomata and regulate desiccation tolerance pathways. Conifers some angiosperms with embolism‐resistant xylem show a peaking‐type (p‐type) response in ABA levels, which levels increase early then decrease as progresses, declining pre‐stressed levels. mechanism behind this dynamic remains unknown. Here, we sought characterise the driving p‐type dynamics conifer Callitris rhomboidea highly drought‐resistant angiosperm Umbellularia californica . We measured leaf water potentials ( Ψ l ), stomatal conductance, ABA, conjugates phaseic (PA) potted prolonged but non‐fatal drought. Both species displayed In branches collected before after peak endogenous planta, that were rehydrated overnight bench dried, biosynthesis was deactivated beyond turgor loss point. Considerable conversion of found occur drought, not catabolism PA. decline may be conserved across seed mediated sustained conjugation deactivation accumulation becomes more negative than loss.

Language: Английский

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Gradients in embolism resistance within stems driven by secondary growth in herbs

Plant Cell & Environment, Journal Year: 2024, Volume and Issue: 47(8), P. 2986 - 2998

Published: April 21, 2024

Abstract The stems of some herbaceous species can undergo basal secondary growth, leading to a continuum in the degree woodiness along stem. Whether formation growth stem base results differences embolism resistance between and upper portions is unknown. We assessed leaves simultaneously within same individuals two divergent that mature bases. were Solanum lycopersicum (tomato) Senecio minimus (fireweed). Basal plants both displayed advanced greater than This also resulted significant vulnerability segmentation species. Greater woodier was found alongside decreases pith‐to‐xylem ratio, increases proportion xylem, lignin content. show there be considerable variation across herbs this linked present. A gradient could an adaptation ensure reproduction or resprouting during episodes drought late lifecycle.

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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Hydraulic traits are coordinated but decoupled from carbon traits in herbaceous species

Functional Ecology, Journal Year: 2025, Volume and Issue: unknown

Published: April 7, 2025

Abstract Plant hydraulic traits primarily define the water regulation strategy, thus enabling a better understanding of vegetation structure, function and dynamics under varying hydro‐environments. Despite being intensively documented in woody species, variation correlation across herbaceous species remain largely understudied. Here, we report on leaf hydraulics nine herbs with contrasting growth forms (graminoid forb). Traits quantifying drought resistance, including potential thresholds triggering xylem embolism (P x ), stomatal closure gs ) or turgor loss point tlp minimum conductance (g min together gas exchange, morphological biomass allocation, were measured pot‐grown plants. In addition, an situ dry‐down was imposed four representative level continuously monitored during dehydration to determine embolism. We found that studied graminoids tended be more tolerant than forbs, although difference safety margin for (HSM st did not differ significantly between these forms. Across P coordinated , but decoupled from exchange traits, maximum photosynthetic rate conductance. Furthermore, no correlations specific area ratio aboveground belowground biomass. For plants experienced dehydration, always preceded onset leaves. Moreover, exhibited distinct strategy despite belonging same form. Our findings contribute herb hydraulics, which will inform prediction grassy ecosystems by providing data guiding classification plant functional types ‘grassy’ ecosystems. Read free Plain Language Summary this article Journal blog.

Language: Английский

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Shoot hydraulic impairments induced by root waterlogging: parallels and contrasts with drought

PLANT PHYSIOLOGY, Journal Year: 2024, Volume and Issue: unknown

Published: June 12, 2024

Abstract Soil waterlogging and drought correspond to contrasting water extremes resulting in plant dehydration. Dehydration response occurs due impairments root transport, but no previous study has addressed whether limitations transport occur beyond this organ or dehydration alone can explain shoot impairments. Using common bean (Phaseolus vulgaris) as a model species, we report that also impairs leaves stems. During the very first hours of waterlogging, transiently dehydrated potentials close turgor loss point, possibly driving rapid stomatal closure partially explaining decline leaf hydraulic conductance. The initial conductance (occurring within 24 h), however, surpassed levels predicted based solely on Constraints resulted disconnection between stems, furthering during after soil drainage. As later embolism initiated extensive amplified damage. stems prevented stem from declining below threshold for critical waterlogging. This allowed plants survive In summary, are central defining thus creating similarities drought. Yet, our findings point existence additional players (likely chemicals) controlling early declines contributing damage

Language: Английский

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Enhanced drought resistance in tomato via reduced auxin sensitivity: delayed dehydration and improved leaf resistance to embolism

Physiologia Plantarum, Journal Year: 2024, Volume and Issue: 176(3)

Published: May 1, 2024

Abstract Auxins are master regulators of plant development and auxin perception mutants display smaller leaves, lower transpiration, narrower xylem vessels than their corresponding wild types. Here, we evaluated whether the leaf embolism resistance overall to drought altered in mutant diageotropica ( dgt ). Our assessments demonstrate that tomato exhibit considerably stems (‐24%), petioles (‐43%), midribs (‐34%) type. Alongside vessels, exhibited greater cell wall thickness‐to‐conduit diameter The water potential at 50% cumulative (P 50 ) type was ‐1.39 ‐1.14 MPa, respectively. Plants also higher stomatal safety margin (water difference between closure P ), needed a longer time reach dry‐down experiment, showed faster recovery gas exchange upon rehydration impaired signaling resulted canopy area conductance, which likely contributed delaying for plants hydraulic damage during drought. These findings clear association structural physiological changes improved against drought‐induced dysfunction mutant.

Language: Английский

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Extreme functional specialization of fertile leaves in a widespread fern species and its implications on the evolution of reproductive dimorphism

Ecology and Evolution, Journal Year: 2024, Volume and Issue: 14(7)

Published: June 29, 2024

Resource allocation theory posits that organisms distribute limited resources across functions to maximize their overall fitness. In plants, the of among maintenance, reproduction, and growth influences short-term economics long-term evolutionary processes, especially during resource scarcity. The evolution specialized structures divide labor between reproduction can create a feedback loop where selection act on individual organs, further increasing specializaton allocation. Ferns exhibit diverse reproductive strategies, including dimorphism, leaves either be sterile (only for photosynthesis) or fertile (for spore dispersal). This dimorphism is similar processes in seed plants (e.g., production flowers leaves), presents an opportunity investigate divergent vegetative organs. Here, we conducted anatomical hydraulic analyses

Language: Английский

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