Soil Rather Than Xylem Vulnerability Controls Stomatal Response to Drought

Carminati, Andrea; Javaux, Mathieu

doi:10.1016/j.tplants.2020.04.003

Cited by 176 publications

(203 citation statements)

References 51 publications

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“…It is widely known that plants sense underground moisture and that these regulatory mechanisms serve to cope with soil moisture variability (Carminati and Javaux 2020;Damour et al 2010;Simonneau et al 1998;Tardieu et al 1992). However, the scientific literature on AMF exerting control on plant moisture reactions has mainly focused on effects in planta while neglecting effects of physical conditioning underground.…”

Section: Discussionmentioning

confidence: 99%

Root growth and presence of Rhizophagus irregularis distinctly alter substrate hydraulic properties in a model system with Medicago truncatula

et al. 2020

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Aim We investigated how substrate hydraulic properties respond to the presence of arbuscular mycorrhizal fungi (AMF) in root-containing and root-free substrate zones in a Medicago truncatula-Rhizophagus irregularis model system. Methods Before planting, two compartments constructed from standard soil sampling cores (250 cm3) were implanted into non-mycorrhizal and mycorrhizal pots containing a sand-zeolite-soil mix. One compartment allowed root penetration (1 mm mesh cover) and the other only hyphal ingrowth (42 μm mesh cover). After eight weeks of growth under maintenance of moist conditions, the cores were subjected to water retention measurements. Additionally, we measured water retention of bare substrates before and after drying events to check for successful maintenance of moist conditions in pots. Results Drying of bare substrates decreased water retention, but planting at least sustained it. The parameters of water retention models responded linearly to root morphological traits across mycorrhizal and non-mycorrhizal substrates. Hyphae-only colonization comparatively affected the course of water retention in ways that suggest increased pore space heterogeneity while maintaining water storage capacity of substrates. Conclusions Hence, water contents corresponded to different substrate matric potentials in non-mycorrhizal and mycorrhizal pots. We conclude that changes to water retention in AMF colonized substrates can contribute to a widely observed phenomenon, i.e. that mycorrhizal plants differ in their moisture stress response from non-mycorrhizal plants.

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Section: Discussionmentioning

confidence: 99%

Root growth and presence of Rhizophagus irregularis distinctly alter substrate hydraulic properties in a model system with Medicago truncatula

et al. 2020

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“…The series of resistances between the bulk soil, soil–root interface and through the root to the leaf xylem were considered in the soil–plant hydraulic model, assuming that one single root represents all active roots that took up water. A detailed description of the model can be found in Carminati and Javaux (2020), Cai et al (2020), Hayat et al (2020) and supplementary note S1 and Table S1.…”

Section: Methodsmentioning

confidence: 99%

“…Carminati and Javaux (2020) re‐proposed the hydraulic model of Sperry and Love (2015) highlighting the role of soil hydraulic conductance ( K s ). Using a meta‐analysis across species, they showed that the loss of K s , more than the xylem, coincides better with the stomatal closure.…”

Section: Introductionmentioning

confidence: 99%

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Stomatal closure of tomato under drought is driven by an increase in soil–root hydraulic resistance

Abdalla

Carminati

Cai

et al. 2020

Plant Cell & Environment

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The fundamental question as to what triggers stomatal closure during soil drying remains contentious. Thus, we urgently need to improve our understanding of stomatal response to water deficits in soil and atmosphere. Here, we investigated the role of soil–plant hydraulic conductance (Ksp) on transpiration (E) and stomatal regulation. We used a root pressure chamber to measure the relation between E, leaf xylem water potential (ψleaf‐x) and soil water potential (ψsoil) in tomato. Additional measurements of ψleaf‐x were performed with unpressurized plants. A soil–plant hydraulic model was used to simulate E(ψleaf‐x) for decreasing ψsoil. In wet soils, E(ψleaf‐x) had a constant slope, while in dry soils, the slope decreased, with ψleaf‐x rapidly and nonlinearly decreasing for moderate increases in E. The ψleaf‐x measured in pressurized and unpressurized plants matched well, which indicates that the shoot hydraulic conductance did not decrease during soil drying and that the decrease in Ksp is caused by a decrease in soil–root conductance. The decrease of E matched well the onset of hydraulic nonlinearity. Our findings demonstrate that stomatal closure prevents the drop in ψleaf‐x caused by a decrease in Ksp and elucidate a strong correlation between stomatal regulation and belowground hydraulic limitation.

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“…After the loss of hydraulic connectivity at the soil-root-interface during prolonged drought (Carminati & Javaux 2020), the amount of internally stored water and its loss via leaky stomata, the cuticle and the bark determine the timing of lethal tissue dehydration (Blackman et al 2016;Choat et al 2018;Duursma et al 2019). Reaching critical desiccation thresholds may thus mark the final step in the dying process of trees rather than being the cause of death.…”

Section: Hydraulic Safety Margins and Non-structural Carbohydratesmentioning

confidence: 99%

Mutually inclusive mechanisms of drought-induced tree mortality

Hajek

Link

Nock

et al. 2020

Preprint

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An extreme summer drought caused unprecedented tree dieback across Central Europe in 2018, highlighting the need for a better mechanistic understanding of drought-induced tree mortality. While numerous physiological risk factors have been identified, the principal mechanisms, hydraulic failure and carbon starvation, are still debated. We studied 9,435 trees from 12 temperate species planted in a diversity experiment in 2013 to assess how hydraulic traits, carbon dynamics, pest infestation, tree height and neighbourhood competition influence individual mortality risk. We observed a reduced mortality risk for trees with wider hydraulic safety margins, while a rising sugar fraction of the non-structural carbohydrate pool and bark beetle infestation were associated with higher risk. Taller trees had a lower mortality risk. The sign and magnitude of neighbourhood effects on mortality risk depended on the species-identity of the involved trees, with most species having beneficial and some having deleterious effects on their neighbours. While severe tissue dehydration causing hydraulic failure precedes drought-induced tree mortality, we show that the probability of this event depends on a series of mutually inclusive processes including pest infestation and starch depletion for osmotic adjustment, and is modulated by the size and species identity of a tree and its neighbours.

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Soil Rather Than Xylem Vulnerability Controls Stomatal Response to Drought

Cited by 176 publications

References 51 publications

Root growth and presence of Rhizophagus irregularis distinctly alter substrate hydraulic properties in a model system with Medicago truncatula

Root growth and presence of Rhizophagus irregularis distinctly alter substrate hydraulic properties in a model system with Medicago truncatula

Stomatal closure of tomato under drought is driven by an increase in soil–root hydraulic resistance

Mutually inclusive mechanisms of drought-induced tree mortality

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