Oxidative Stress Study of Jatropha Curcas Seeds Subjected to Salt Stress During Germination and Seedling Development

Abstract

SUMMARY: Jatropha curcas L. is an oilseed plant that has been considered an alternative crop for semiarid regions, due to its adaptability to water deficit. This study aimed to evaluate the salt stress effects on germination and the antioxidative system of J. curcas seeds and seedlings. The germination parameters were significantly affected by salt treatment, and the percentage of seed germination was the most affected. The activities of antioxidative enzymes [superóxido dismutase, catalase (CAT), peroxidases do ascorbato e guaiacol] were significantly increased in salt-stressed endosperms and embryo axes at 6 and 8 DAS. Among these enzymes, CAT showed to be the strongest involved in hydrogen peroxide scavenging, due to CAT highest values in all evaluated periods, especially in salt stress conditions after germination. The lipid peroxidation was significantly highest until 4 DAS in control conditions; thereafter, these values sharply decreased. In addition, it was noticed that the antioxidative enzymes were not completely effective in avoiding the oxidative damages promoted by salt stress, which can have contributed to the high levels of lipid peroxidation, mainly at 6 and 8 DAS. We assumed that the increase in J.curcas antioxidant enzymatic system in the salt stress response may represent an adaptive condition to seed germination in saline conditions. KEYWORDS: Antioxidative enzymes, Lipid peroxidation, NaCl stress. AVALIAÇÃO DO ESTRESSE OXIDATIVO EM SEMENTES DE PALAVRAS-CHAVE:Enzimas antioxidativas, peroxidação lipídica, estresse salino.