Drought-tolerance mechanisms in rumberry, a native Brazilian fruit species

Abstract

Abstract The objective of this work was to characterize the physiological and biochemical responses related to drought tolerance in rumberry (Myrciaria floribunda) plants. The experiment was carried out on plants aged about 2.5 years, which were grown in a greenhouse and subjected to two water conditions, as follows: well-watered soil (at field capacity) and water stress (suspension of irrigation for 30 days), with ten replicates per treatment. The following parameters were evaluated: number of leaves; relative water content; electrolyte leakage; photosynthetic pigment concentrations; photochemical efficiency of photosystem II; osmolyte contents; malondialdehyde concentration; and the antioxidant enzymatic activity of superoxide dismutase, catalase, and ascorbate peroxidase. The water stress regime resulted in reduced the relative water content, the potential and effective efficiency of photosystem II, total soluble proteins, and superoxide dismutase activity. No significant changes were observed for the number of leaves, electrolyte leakage, photosynthetic pigment concentrations, and total soluble sugar content, or malondialdehyde concentrations. Conversely, water stress induced increases of total soluble amino acids, free foliar proline, and the activity of catalase and ascorbate peroxidase. The activation of osmoprotective and antioxidant mechanisms, associated with the maintenance of cellular integrity, confers tolerance of rumberry to water stress.