Connecting the dots between root, xylem and stomata
| Autor: | Rodríguez Domínguez, Celia M., Duddek, Patrick, Burlett, Regís, Cochard, H., Delzon, Sylvain, Mantova, Marylou, Torres Ruiz, José Manuel, Trueba, Santiago, Bourbia, Ibrahim, Brodribb, Timothy J., Mutez, A. Ahmed |
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| Přispěvatelé: | CSIC - Patronato Juan de la Cierva de Investigación Científica y Técnica |
| Jazyk: | angličtina |
| Rok vydání: | 2021 |
| Předmět: | |
| Zdroj: | Digital.CSIC. Repositorio Institucional del CSIC instname |
| Popis: | 2 páginas.- 3 referencias.- Comunicación oral presentada en el BP2021: XXIV Reunión de la Sociedad Española de Biología de Plantas y XVII Congreso Hispano-Luso de Biología de Plantas, 7 y 8 de julio de 2021. online Stomata are present on all land plants and are key features for vascular plant water content regulation on Earth. Their primary function, i.e., stomatal closure to control water los s under soil and atmospheric drought, is Ihought to prevent cavitation in the vascular system (Brodribb et al. 2017). However, stomata are found to close much before the xylem cavitates - i.e., the leaf water potential at which stomata close by 50% (IV gs50) is much less negative than the water potential at which the xylem loses 50% of its conductivity (lV_x50) (Martin-St Paul et al. 2017). The mechanism that would allow sto mata to close promptly to a decrease in transpiration in relation to a change in leaf water potential before the decrease in hydraulic conductance is still elusive. Our hypothesis is that the loss of root-soil hydraulic conductivity, more than xylem vulnerability to embolisms, is Ihe primary constraint on transpiration during drought (RodriguezDominguez and Brodribb 2020). Thus, sto mala would close when the water potential around the roots drops more rapidly than the increase in transpiration. We investigated whether this loss of root-soil hydraulic conductivity, probably caused due to root shrinkage and the formation of air-filled gaps, aml/or damage to fine roots, appeared to be an important constraint on transpiration during drought. We conducted physiological and imaging experiments on maize plants undergoing moderate drought. We performed highresolution imaging (micro-CT) of leaves and the root-soil interface and measured in parallel the soil and plant water potentials. Transpiration, stomatal conductance, root hydraulic conductance and soil and plant water potential were also measured during soil drying in a similar set of plants. The formation of air-filled gaps along individual maize roots was visualized and quantified, finding an agreement between the soil water potential at which roots shrank and root hydraulic conductance decreased, and the soil water potential at which sto mata c1osed. These results proved the hypothesis that the loss of contact between roots and soil, and probably other root cortex modifications, triggered stomatal c10sure and transpiration reduction. Microcomputed tomography measurements were conducted at the PSYCHE beamline at SOLEIL Synchrotron (Paris, France). C.M.R-D. was supported by a "Juan de la Cierva - Incorporación" post-doctoral fellowship (Spain) and was granted a Junior Fellowship by the University of Bayreuth Centre of Intemational Excellence "Alexander von Humboldt" for conducting this specific experiment. |
| Databáze: | OpenAIRE |
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