Dormência em sementes de pupunha (Bactris gasipaes Kunth): uma abordagem anatômica, histoquímica e fisiológica

Abstract

Bactris gasipaes is an important palm for populations in the Amazon, mainly due to the value nutritional content of its fruit. This work is divided into four chapters and the overall goal was evaluate anatomical, histochemical and physiological aspects and their relationships with mechanisms of dormancy in seeds of Bactris gasipaes. In the first, aimed identify anatomical and histochemical seed of B. gasipaes associated with the process dormancy and germination. The integument is thin and in two layers, the outer thicker cell where checks for the presence of vascular bundles and the inner less thick, with irregularly shaped cells and filled with phenolic compounds. The endosperm occupies the most of the seed and is whitish, with cells in oboval oblong and oval, with lipid content. The embryo is small in relation to seed size, conical, undivided and vascularized in the distal portion. In proximal region in cross section appears plumule, with three leaf primordia. In the second chapter aimed to quantify phenolic compounds in seeds of B. gasipaes fruit in two stages of maturation, correlating them with the emergence of seedlings and check the effect of applying the extract these seeds in the germination of Lactuca sativa. The emergence, emergence rate index, mean emergence time, coefficient of uniformity emergency, synchronization index, average speed of Emergency, emergency value and coefficient of emergence rate did not vary significantly seeds obtained from immature and mature fruit. However, variations of these same variables were higher among seeds of different plants. Seeds mature peach palm have higher concentration of phenolic compounds and the accumulation of immature compounds is one of the factors responsible for reducing germination in seeds of peach. The phenolic extract of seeds of this species was able to reduce and delay germination and emergence of lettuce seeds and that Emergency correlated significantly with the emergence of seedlings of peach palm. The water content of seeds of immature fruits was statistically superior that of mature seeds (50.4 and 46.7%, respectively). In the third chapter aimed to assess the lipid composition and the melting point of seed lipids of B. gasipaes and correlate them with variables related to emergency seedlings from seeds from fruits immature and mature. The melting point of lipids not differ statistically between fruit seeds immature (22.54 °C) and mature (22.70 °C), but was discharged correlation with the variables related to the emergence of plantlets. The levels of oleic and linoleic acid were higher in mature seeds (26.89 and 30.66 μg.g-1, respective entity) in relation to fruit immature (22.01 and 24.79 μg.g-1, respectively). The oleic acid concentration was negatively correlated with the mean emergence time (MET). The fourth chapter aimed to investigate the presence of numbness embryo in seeds of peach palm. Most variables related to the emergence of seedlings from seed in the nursery, and germination of embryos in medium, varied significantly between plants and origins. In general, these were related positively, ie higher germination, greater the emergency. The structural characteristics indicated that the embryo is differentiated at the time of scatter. The presence of phenolic compounds and terpenoids in the seed coat may be one of the factors that inhibit the germination of peach palm. The emergence seedlings did not differ between fruit seeds immature and mature. Mature seeds have highest concentration of phenolic compounds that seeds immature fruits and accumulation of phenolic compounds is able to inhibit the germination of seeds of peach palm. The lipid concentration was higher in fruit seeds immature and mature seeds showed higher concentrations of oleic and linoleic acids. The higher concentration of oleic acid results a lower average time of emergence. The higher the melting point of the lipids, the greater the emergence and emergency speed index. It was evident that the seed dormancy of peach can be attributed in part to embryo dormanc