Effects of H2O2 on the growth and solutes accumulation in maize plants under salt stress

The aim of this study was to evaluate the effects of foliar application of H2O2 on plant growth and on the levels of organic and inorganic solutes in maize plants under salt stress. The experiments were conducted in a greenhouse under hydroponic conditions. Eight days after sowing, the seedlings were sprayed with a 10 mM H2O2 solution or with distilled water (as a control). Forty-eight hours after the beginning of spraying, they were subjected to treatment with NaCl at 80 mM. Two harvests were carried out: 96 and 240 hours after the start of spraying. The experimental design was completely randomized following a factorial arrangment 2 (NaCl at 0 or 80 mM) x 2 (H2O2 at 0 or 10 mM), with five replicates. The data for each harvest time (96 or 240 h) were submitted to analysis of variance (ANOVA) and the means were compared through Tukey's test (P <= 0.05).The results showed that foliar application of H2O2 produced acclimation of the plants to salt stress, decreasing the deleterious effects of salinity on the growth of the maize. This effect can be attributed, at least partially, to a larger build up of proteins, and soluble carbohydrates and NO3- as well as lower levels of Cl- and Na+ in the foliage.