Caracterização anatômica e bioquímica de sementes de açaizeiro (Euterpe oleracea Mart.) durante a germinação em condições de anoxia e normoxia

Abstract

The açaizeiro (Euterpe oleracea Mart.) is palmaceae of the great economical importance that is very common in Amazonas river, mainly in low and flat land alongside a water course, where is common the intermittent inundations. In spite of its importance and high tolerance to low availability oxigen conditions, its strategies to tolerate hypoxia and/or anoxia are unknown. The objective of this paper was to characterize the anatomical aspects of seeds and plantlets of açaizeiro, giving informations to study plantlet and seed reserve degradation, during anaerobiosis. The results of anatomical characterization showed that the seeds of “açaizeiro” are ruminated (ruminated front), its endosperm is formed by cells from different sizes and shapes, with thick walls and very pontuation, its embryo is formed by root-hypocotil axis, procambium and parenchym with various idioblasts with rafids and that the endosperm of seed, the basis of shoot and haustory are the place for starch accumulation. After submit the seeds and plantlets to different times of anoxia, it is possible to conclude that the “açaizeiro” seeds could stand until four months of anoxia, germinating after the transference for normoxic conditions, the tolerance of seeds and plantlets are related to maintenance of amylolytic activity: the enzyme α-amylase is pre-existing in seeds of açaizeiro, the enzyme endo β-mananase is not synthetized in seeds during the anoxia, the enzyme endo β-mananase is synthetized “de novo” in seeds, the haustory is a initial synthesis site of endo β-mananase in seeds of açaizeiro germinated in normoxic conditions.