Alterações fisiológicas em sementes durante o armazenamento e estabelecimento de plântulas de pequizeiro

Abstract

This study aimed to evaluate the physiological changes in seeds during storage and the use of irrigation on the establishment and growth of pequi tree seedlings. In the first study, pyrenes (seeds involved by the endocarp) were stored in an environmental condition and evaluated over a year. Between 40 and 60 days of storage, there was reduction in water content and an increase in oxidative stress, which led to reduction in synthesis and ABA accumulation and numbness relief. After this period, limitations in the control of oxidative stress caused a gradual reduction in the synthesis and accumulation of ABA and loss of membrane functionality, which resulted in seed deterioration. In the second study, the effect of water availability (through irrigation) and time (six evaluations), over a year, on pyrene germination, seedling survival and morphology and hypocotyl anatomy (subterranean stem structure) was evaluated. Irrigation provided greater germinability (55%) than dryland conditions (44%). Irrigated plants had greater stem length and diameter as well as number of leaves and leaf area than non-irrigated plants. Irrigation also favored root development in the last evaluation periods. Hypocotyl was persistent, with secondary growth positively influenced by water availability. Seedlings and young plants of C. brasiliense were remarkably resistant to drought. However, the use of irrigation favored their establishment and development.