Composição química e suplementação mineral em sementes de soja: qualidade fisiológica, desenvolvimento de plântulas e aspectos produtivos

Abstract

Soybean is the main aleuro oleaginous cultivated in the world and are used for several ends such as human and animal food and biofuel. Nevertheless, the productivity is still below the productive potential. Among the factors, which limit high productive levels to be achieved, is the use of quality seeds, which determine the stand of plants in the field. The seed physiological quality depends on, among other factors, its chemical composition, because the nutrients stored in the reserves are fundamental for the growth of the embryo and seedling development. Therefore, seedlings originated with higher nutrient availability will originate seedlings that are more vigorous. Thus, this work aimed to evaluate the influence of the chemical composition of seeds and the contribution of mineral supplementation through the treatment of seeds in physiological quality, seedling initial development, activity of enzymes related to the vegetal metabolism and grain productivity. Chapter I aimed to evaluate the influence of different levels of soybean seeds mineral chemical composition as well as the efficiency of mineral supplementation through seed treatment in physiological quality and field performance. Chapter II concerned about evaluating the contribution of N derivate from the mineral supplementation in seeds with different nutritional content, for soybean seedlings. Chapter III aimed to evaluate the influence of nutritional content and mineral supplementation through seed treatment in germination, initial development and enzyme activity related to vegetal metabolism of soybean seedlings. The chemical composition of seeds influenced the physiological quality and the seed field and laboratory performance. The seeds, which derivate from the lot with lower nutritional content, absorbed more N from the mineral supplement, which was accumulated in the cotyledons and redistributed to the root system and canopy. Most of the N in soybean seedling organs, along 10 days after the seeding derivate results from seed reserves, in lots with low and high nutritional content, thus the application of N through mineral supplementation is of low importance to nutrition and development of seedlings. The amount of stored reserves influences the physiological quality and early development of seedlings. Mineral supplementation via seed treatment influenced the physiological quality and seedling development on the lot of low nutritional value. Mineral supplementation influenced the activity of α-amylase in the cotyledons and POD and APases in shoots of seedlings from seed lot of low nutritional value.