Biochemical and physiological changes in Dipteryx alata Vog. seeds during germination and accelerated aging
2020
Silva, G.P. | Sales, J.F. | Nascimento, K.J.T. | Rodrigues, A.A. | Camelo, G.N. | Borges, E.E.D.L.
Dipteryx alata Vog. is a forest species native to the Brazilian Cerrado with great economic potential, but information on seed behavior during germination and accelerated aging is lacking. Thus, the objective of this study was to evaluate the quality of D. alata seeds during germination and to measure the possible damage caused by aging. The physiological performance of D. alata seeds was investigated via two experiments: (1) imbibition curve, where the seeds were stored in a Biochemical Oxygen Demand chamber (B.O.D) at 30 °C and 60% of relative humidity (RH), for eight days, and (2) accelerated aging, where the seeds were stored in a B.O.D at 42 °C and 60% of RH, for 96 h. In the experiment 1, α- and β-amylase activity and histochemical changes were determined in endosperms and embryos collected at 0, 6, 12, 24, 36, 48, 96, 144 and 196 h after imbibition. In the experiment 2, respiratory activity, electrical conductivity, and catalase, superoxide dismutase and peroxidase activity, as well as protein content and vigor tests, were determined in embryos collected at 0, 48, 72 and 96 h after accelerated aging treatment. The results indicated that α- and β-amylase synthesis was activated after 48 h of imbibition, culminating in starch degradation. Concomitant with starch degradation, lipids and proteins were consumed throughout the germination process. Accelerated aging promoted an increase in respiration, electrical conductivity and peroxidase activity as well as a reduction in superoxide dismutase and catalase activity. And, although the germination rate of D. alata seeds was not compromised by accelerated aging, a decrease in the germination speed index was observed over time. Thus, together, these biochemical and physiological changes can be used as markers of D. alata seed deterioration induced by high temperatures and humidity.
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