Métodos de aplicação e concentrações de ácido ascórbico no cultivo de maracujazeiro-azedo irrigado com águas salinas

Abstract

Salinity is one of the abiotic stresses that most limits the development of irrigated fruit growing in semi-arid regions of Brazil. In this sense, it is extremely important to search for strategies that minimize the effects of salt stress, such as the use of eliciting substances such as ascorbic acid; however, the beneficial effects depend on the application method and the concentrations used. Therefore, the objective of this study was to evaluate the effects of application methods and concentrations of ascorbic acid on the growth, physiology and production of sour passion fruit irrigated with saline water. The treatments were distributed in a randomized block design, in a 3 × 3 × 2 factorial scheme, corresponding to three application methods (soaking, spraying and soaking + spraying), three concentrations of ascorbic acid (0; 0.8 and 1.6 mM) and two levels of electrical conductivity of irrigation water - ECw (0.8 and 3.8 dS m-1) with three replications, totaling 54 experimental plots and one plant per plot. Regarding the results, foliar spraying of ascorbic acid at a concentration of 0.8 mM mitigated the effects of saline stress on the relative leaf water content, the synthesis of photosynthetic pigments, gas exchange and the total production of sour passion fruit fruits. when irrigated with Cea of 3.8 dS m-1. Plants grown with water of 0.8 dS m-1 and foliar application of 0.8 mM ascorbic acid achieved the greatest growth in stem diameter and the greatest volume of pulp in the fruits.