Implications of the fatty acids and carbohydrate variation during maturation upon Poincianella pluviosa (sibipiruna) seeds storability

Abstract

The maturation cycle of Poincianella pluviosa (DC.) L.P.Queiroz (Caesalpinioideae) seeds is longer than the period of seed storability at room temperature (11 and 8 months, respectively), requiring specific strategies to guarantee its propagation. The objective of this study was to analyze soluble carbohydrates, triacylglycerols, and membrane fatty acids during maturation of P. pluviosa seeds in order to evaluate the involvement of these compounds in seed behavior after shedding. Seeds of P. pluviosa accumulate large quantities of oil (~45%, mainly linoleic acid) compared to starch and soluble carbohydrates (both ~9%), and they are composed mainly of sucrose, cyclitols, and traces of raffinose and stachyose. Intriguingly, a decrease in the ratio of unsaturated fatty acids during maturation was observed mainly in membrane constituents of the embryonic axis. A decreased ratio of sucrose to raffinose was also observed in the axis and in cotyledons during maturation and could be related with the short storability of mature seeds. However, the low proportion of most unstable unsaturated fatty acids on maturity could contribute to the integrity of membranes, avoiding oxidative stress during water loss. These results provide evidence that seeds of P. pluviosa present antagonistic mechanisms that implicate on seed storability behavior.