Antioxidative enzymes of Cucumis sativus seeds are modulated by Leucaena leucocephala extracts

摘要

This study aimed to analyze oxidative stre ss produced in cucumber seeds and seedlings when exposed to aqueous extract from dried leaves of leucaena, as well as its effect on the germination behavior, early growth and the antioxidant enzymes ac tivity. It was evaluated the percentage, the speed index, the average time, the frequency and germination synchronization, the root length and shoot, as well as the catalase and peroxidase enzymes activity. Ther e was no significant inhibitory effect of the leaf extracts on the germination percentage. However, ther e was delay in the seeds ge rmination, as the extract proportion increased. A stimulatory effect of the extract compared to the shoot length was observed, however the root growth was signific antly reduced. The catalase activities had a peak at 24 hours after soaking the seeds, however, the activi ties were reduced in seedlings. The peroxidase activity was low in the seeds and increased in the seedlin gs at 168 hours after immersion. Th e results suggest that there was oxidative stress due to allelochemicals present in the le aves extracts from leucaena, verified by germination and initial growth changes, causing alterations in the plants rootlets.