Proteins expression and germination of maize seeds submitted to saline stress

Plants are frequently exposed to various biotic and abiotic stresses that impair their growth, development and limit the productivity. In the present work the objective was to evaluate the effect of saline stress on the germination and biochemical alterations by the expression of enzymatic systems in corn seeds treated with different concentrations of NaCl. Hybrid maize seeds (H1, H2, H3) were used during 2013 cropping season and solutions of sodium chloride (NaCl) to simulate the saline stress. The respective concentrations of NaCl (mol.m-3) were zero (0.0 g/L); 25 (1.46 g/L); 50 (2.93 g/L); 75 (4.39 g/L) and 100 mol.m-3 (5.85 g/L), diluted into water. In order to evaluate the physiological potential of these seeds, we realized the germination test with four replications of 50 seeds, distributed between three germitest papers moistened with NaCl solutions, described above. The evaluation was performed on the seventh day, with the first count realized determining the percentage of normal seedlings on the fourth day after planting. The biochemical evaluation was performed by the expression of isoenzymes superoxide dismutase (SOD), esterase (EST), catalase (CAT), alcohol dehydrogenase (ADH), malate dehydrogenase (MDH) and alpha amylase. Seeds of the three tested hybrids have lower germination when placed in conditions of greater concentration of salinity. The hybrid H3 that presents higher tolerance to salinity and hybrid H1 are most susceptible during the germination process. The hybrid with higher vigor, H3 had higher activity of alpha amylase and catalase enzyme groups. Esterase and alcoholic dehydrogenase were not effective in measuring the quality of maize grains under salt stress conditions. Key words: Zea mays, physiological quality enzyme.