Indução à tolerância ao estresse salino em cebolinha mediante priming com H2O2 em cultivo hidropônico.

Abstract

The hydroponic system with the use of saline water is an alternative for the production of vegetables in the Brazilian semiarid, however, salts when in high concentration can reduce agricultural production. One technology to mitigate the effects of salinity consists of acclimatizing seeds with hydrogen peroxide, which can act as a signaling molecule, capable of inducing tolerance responses to salt stress. Thus, the objective of this study was to evaluate the induction of tolerance to salt stress by priming with H2O2 in hydroponic cultivation. The experiment was conducted in a protected environment belonging to the Federal University of Campina Grande. The experimental design was in randomized blocks, in a 5 x 5 factorial arrangement, with five levels of electrical conductivity of the nutrient solution: 1.0; 2.0; 30; 4.0 and 5.0 dSm-1 and five hydrogen peroxide concentrations 0.0; 0.15; 0.30; 0.45 and 0.60 mmol, with three replicates and three plants per subplot. The concentrations of hydrogen peroxide were applied by soaking the seeds for 24 hours. The growth variables were evaluated: plant height, number of leaves, length and diameter of the bulb, fresh biomass and dry bulb biomass, fresh biomass and dry leaf biomass. Pigments were also evaluated; chlorophyll a, chlorophyll b and carotenoids and the contents of H2O2, amount of malondialdehyde (MDA) and the activity of catalase in chive plants. The use of hydrogen peroxide as a priming in chives seeds induced the tolerance of plants to salt stress, minimizing the deleterious effects of the salinity of the nutrient solution on growth, pigments and production. The increase in the salinity of the nutrient solution promoted an increase in the content of hydrogen peroxide, lipid peroxidation. The acclimatization of chive seeds with hydrogen peroxide at a concentration of 0.45mmol in plants that were grown in the 3.73 dSm-1 nutrient solution obtained the maximum activity of the catalase enzyme.