Influence of Silicon on Tolerance to Water Deficit of Peach Trees

Abstract

Water deficit in young fruit trees can reduce growth and future orchard productivity. Exogenous silicon (Si) applications have been associated with induced resistance to biotic and abiotic stresses such as water deficit, but the role of Si in fruit trees is still largely unexplored. The aim of the study was to evaluate the effect of Si applications on water status and gas exchange of young peach trees. This study comprises two experiments arranged in a factorial design with two water regimens (well-irrigated or water-stressed) and three Si concentrations (0, 10, or 20 mg⋅L−1 in the first experiment; 0, 20, or 40 mg⋅L−1 in the second experiment). Si applications via foliar spray were performed weekly after the water regimens were clearly established. Tree water status (midday stem water potential), and gas exchange parameters (CO2 assimilation, leaf transpiration, stomatal conductance, leaf water use efficiency) were measured. Si application at 10 or 20 mg⋅L−1 improved water status of water-stressed trees without affecting gas exchange, but 40 mg⋅L−1 reduced CO2 assimilation. Thus, foliar applications of Si could be a promising strategy for nonirrigated, nonbearing orchards to maintain their water status during dry periods and/or improve their recovery from water deficit.