Leaf water absorption and oxidative stress in Velloziaceae species with contrasting drought tolerance strategies

Abstract

Velloziaceae species that occur in rocky outcrops may present contrasting strategies for water use: while some species remain green during drought, so-called resurgents tolerate vegetative desiccation and recover metabolic activities after rehydration. Atmospheric water (mist, dew) is a potentially important water source for species of these environments, but little is known about the effects of this hydration strategy on the physiology and metabolism of these plants. The objective of this project is to evaluate if the absorption of leaf water occurs and can minimize the effects of drought, facilitating the rehydration process and modulating responses in the different functional levels of Vellozia nivea (resurrection) plants when compared to Vellozia intermedia (always green). We will evaluate if the acquisition of water by the leaves can attenuate the effects of embolism in the xylem vessels and we intend to understand how the expression of genes related to drought controls the different metabolic strategies and oxidative stress. The controlled experiment will be performed with hydrated plants and submitted to water deficit, with different levels of air humidity. This project is innovative because it aims to integrate plant responses to different types of drought (in soil and atmospheric) and rehydration modes (by roots and leaves) at different scales (physiological, metabolic and genetic). The results will elucidate the adaptive mechanisms essential for the survival of species exposed to drought, and generate important scientific contributions for the future of applied research on drought tolerance in sensitive species.