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Titre : Effect of Arbuscular Mycorrhiza Fungi on Transpiration and Leaf Water Potential in Drought-Stressed Maize

Auteur : Heroux, Kelly Mae :

Université de soutenance : Universität Bayreuth

Grade : Master of Science 2021

Résumé
Stomata behavior has profound implications for water fluxes between soil and the atmosphere. It remains unknown what exactly triggers stomata closure when there is a soil water deficit. Meanwhile, it is understood that arbuscular mycorrhizae fungi (AMF) improve the water retention quality of soils and root water uptake. The objective of this study was to demonstrate a link between the influence of AMF on the water status of maize plants when exposed to drought. It was hypothesized that soils in the rhizosphere of plants inoculated with AMF have a less severe drop in soil matric potential, allowing for increased and extended water uptake at the soil-root interface during soil drying, and subsequently, as soil dried, an enhanced plant water status would be observed for inoculated plants. To test these hypotheses, measurements were taken of transpiration rates, soil water content, leaf water potential, above- and belowground biomass, and root morphology of maize grown with and without AMF inoculation and exposed to drought conditions. The results demonstrated that, as soil dried, AMF symbiosis allowed for a more gradual decline of leaf water potential, facilitating both higher and sustained transpiration rates when compared with plants grown without AMF inoculation. It is concluded that AMF supported Data fields EPub Bayreuth maintaining the hydraulic continuity between maize roots and drying soils, reducing the drop in matric potential at the root-soil interface. These findings express the importance in linking AMF colonization with plant hydraulics and stomatal conductance to improve plant resistance to drought, as well as supporting more precise predictions of plant response to soil drying, especially in the face of climate change.

Mots clés  : arbuscular mycorrhiza fungi ; AMF ; transpiration ; leaf water potential ; drought-stress ; maize

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