Cultivo de mini-melancia sob irrigação com águas salinas e aplicação foliar de peróxido de hidrogênio.

Abstract

In the semi-arid region of Northeastern Brazil, due to the occurrence of water sources with excess salts, plants are constantly exposed to different conditions of abiotic stress, and the effects of these salts on plants are related to the reduction of osmotic potential, the specific action of ionic concentration and nutritional and hormonal imbalance. Thus, it is extremely important to identify alternatives capable of minimizing the effects resulting from saline stress on plants. In this context, the objective of this research was to evaluate the growth, physiology, production and post-harvest quality of mini-watermelon trees as a function of irrigation water salinity and foliar application of hydrogen peroxide. The research was carried out in pots under greenhouse conditions, in the municipality of Pombal, PB, using a randomized block design in a 5 × 4 factorial scheme, corresponding to five levels of electrical conductivity of irrigation water - ECw (0.3; 1.0; 1.7; 2.4 and 3.1 dS m-1) and four concentrations of hydrogen peroxide – H2O2 (0; 20; 40 and 60 μM) with three replications. Water salinity from 0.3 dS m-1 increased electrolyte leakage in the leaf blade, carotenoid and ascorbic acid contents, and reduced the relative water content, osmotic potential, growth and the synthesis of chlorophyll a and b and the production of mini-watermelon plants. The foliar application of hydrogen peroxide up to a concentration of 60 μM increased the levels of ascorbic acid in the fruits of mini-watermelon cv. Sugar Baby.