Activity of antioxidant enzymes and proline accumulation in Erythrina velutina Willd. seeds subjected to abiotic stresses during germination1

ABSTRACT- The aim of this study was to evaluate the effect of different abiotic stresses on the activity of antioxidant enzymes and on accumulation of proline in Erythrina velutina Willd. seeds during germination. Mulungu seeds were scarified and placed to germinate at constant temperatures of 15, 25, and 35 °C, moistened with distilled water, and exposed to 12 h of light. Other seeds were exposed to solutions of NaCl (EC of 0, 4, and 8 dS.m-1) and polyethylene glycol (osmotic potentials of 0.0,-0.2, and- 0.6 MPa) and maintained in a germination chamber set at 25 °C and 12 h photoperiod for seven days. At the end of each period of imbibition, the embryonic axis and cotyledons of the seedlings were collected separately and used to quantify proline content and the activity of antioxidant enzymes. These were detected in both the cotyledons and embryonic axis of the mulungu seeds. Antioxidant activity varied depending upon the type and degree of stress applied. It was concluded that under the aspect of the detoxification process, the mechanism found in mulungu seeds is more efficient when subjected to different temperatures followed by salt stress and water stress. Index terms: antioxidative metabolism, water stress, salt stress, heat stress, mulungu. Atividade de enzimas antioxidantes e acúmulo de prolina em sementes de Erythrina velutina Willd. submetidas a estresses abióticos durante a germinação RESUMO- Objetivou-se com este trabalho avaliar o efeito de diferentes estresses abióticos na atividade das enzimas antioxidantes e no acúmulo da prolina em sementes de Erythrina velutina Willd. durante a germinação. Sementes de mulung