Ecofisiologia de abobrinha italiana sob estresse salino com aplicação exógena de H2O2 em cultivo hidropônico.

Abstract

The use of brackish water in the semiarid region is an alternative to produce in the period of water scarcity. Therefore, it is essential to apply saline stress attenuators to minimize the deleterious effects of salts on crop growth and production. In this context, the present work aimed to evaluate the attenuating effect of hydrogen peroxide on saline stress in zucchini plants grown in a hydroponic system. The work was carried out in a greenhouse, in Pombal - PB, using a completely randomized design, in a 4 × 4 factorial scheme, with four levels of electrical conductivity of the nutrient solution - ECsn (2.1 - control; 3.6 ; 5.1 and 6.6 dS m-1), and four concentrations of hydrogen peroxide – H2O2 (0; 20; 40 and 60 μM), with three replications. Using the hydroponic cultivation system type Laminar Nutrient Flow Technique. The nutrient solution with electrical conductivity of 2.1 dS m-1 and hydrogen peroxide spraying at concentrations of 40 and 60 μM promoted an increase in stem diameter and root length. However, the salinity of the nutrient solution above 2.1 dS m-1 reduced the levels of photosynthetic pigments, gas exchange, growth and dry phytomass accumulation. The concentration of 20 μM H2O2 and 2.1 dS m-1 nutrient solution increased the total fruit weight and basal diameter of zucchini fruits. The increase of ECsn and the concentration of H2O2 alone reduced the pH and the number of fruits.