Qualidade fisiológica de sementes e metabolismo antioxidante de plântulas de soja produzida na região do Baixo Parnaíba Maranhense

Abstract

The use of high seeds quality is the basis for the success of the crop. The production of soybean seeds in the region of Baixo Parnaíba Maranhense is a great challenge due to this region has climatic limitations that do not support the production of high seeds quality. Besides that, the way of storing seeds is an important step to maintaining seed quality. The objective of this study was to evaluate the physiological seeds quality and the antioxidant metabolism of soybean seedlings produced in the Baixo Parnaíba Maranhense region, after different storage periods. Two experiments were conducted in this study. The first study included lots with higher quality seed. The second study included lots with lower quality seed. The seeds of BRS 333 RR, PAMPEANA 20 RR, and PAMPEANA 10 RR cultivars were used. The experimental model used to analyze seed quality was a split-plot completely randomized experimental design with four replications. The seeds were subjected to the moisture content, the seed quality (germination, first germination count, accelerated aging, electrical conductivity, field emergence, and respiratory activity tests), and antioxidant metabolism of enzymes. Soybean seeds of different cultivars show different behavior during storage under controlled conditions. The reduction of soybean seed quality during storage does not occur at the same speed for all cultivars. The soybean seeds of BRS 333 RR cultivar have a high potential of storage, with smaller reductions in seed quality during the storage under controlled conditions. The PAMPEANA 20 RR cultivar presents high storage potential, when used high vigor lots, maintaining their quality up to six months of storage, without major reductions in quality under controlled conditions. The seeds of the PAMPEANA 10 RR cultivar present higher quality reductions during storage. The BRS 333 RR cultivar has an efficient antioxidant system in the removal of reactive oxygen species, maintaining the quality of seeds. The seeds of PAMPEANA 10 RR cultivar shows an increase in the antioxidant enzymes activity, during certain periods of storage, but this is not enough to maintaining the quality of the seeds.