Peróxido de hidrogênio como amenizador da suscetibilidade do milho verde ao estresse salino.

Abstract

The salinity is one of abiotic factors that most affect negatively in the productivity of crops, among them, the green corn, for providing reduction in osmotic potential and effects ion order, thus hindering their growth, development, and consequently production. In the case of arid and semi-arid regions, salinity constitutes a serious problem, limiting the agricultural production and reducing the crop yields to uneconomical levels. In this scenario, alternatives that aimed at mitigating the deleterious effects of salinity are of the fundamental importance; thus aimed to evaluate the hydrogen peroxide as reliever of the susceptibility of the green corn to salt stress. The experiment was conducted in the Science and Technology Center Agrifood Campus Pombal - Pombal / PB belonging to the Federal University of Campina Grande (CCTA - UFCG) in the period from 10/01/2015 to 15/02/2015, using a hybrid corn 'AG 1051'. Cultivation was carried out in pots with a capacity of 8 dm3 of soil, filled with soil classified as a VERTISOL. The treatments were constitute by two levels of salinity of the water of irrigation (0.3 and 2.0 dS m-1) and five different hydrogen peroxide concentrations (0, 40, 80, 160 and 320 mmol L-1) applied via irrigation water. The experimental design was completely randomized in a factorial 2 x 5, with four replications. The experimental unit consisted of a pot containing two plants. The pots were arranged with spacing of 0.5 x 0.5 m. It was evaluated the gas exchange, pigment chlorophyll and carotenoids, growth and accumulation of mass in the plant. The higher values for physiological parameters, growth, dry matter accumulation and levels of chlorophyll and carotenoids were observed in water salinity of 0.3 compared to 2.0 dS m-1. The supply of H2O2 reduces in corn plants, stressful effect caused by salinity irrigation water concentrations between 40 and 80 mmol L-1. The salinity of the irrigation water coupled with the high concentrations of H2O2 caused a reduction in photosynthesis in the early growth of plants in the dry matter accumulation and chlorophyll and carotenoid content.