Tolerância de sementes de soja à dessecação

Abstract

The anticipated harvest of seeds after physiological maturity allows the obtaining of the better quality physiological, crop rotation and optimization of the processing structures. Seeds do not tolerate dissection over all the stages and acquire tolerance in particular stages During maturation, this acquisition of dissection tolerance may coincide with physiological maturity and in soybean seeds, it take place at R7 stage with moisture close from 45% to 50%. So, the present research was intended to evaluate dissection tolerance of soybean seeds. The seeds were harvested at three phenologic stages, R6, R6/R7 and R7 and were submitted to artificial drying at 35ºC to 20% of water content and at 42ºC to 13%. A fourth harvest was accomplished with field dried seeds, these being utilized as a control. The quality of seeds was evaluated by tests of germination, electric conductivity and of cold, of dry weight of seedlings and lea protein electrophoresis.The experimental design was completely randomized in factorial scheme with four replicates. The control was compared singly with each treatment. From the results, it follows that both germinability and dissection tolerance of soybean seeds increase with the natural water loss in the field; seeds harvest at R7stage show increased physiologic quality, distinct pattern of lea proteins and greater dissection tolerance than at R6 and R6/R7stages; seeds drying harvested close to maturity induces the synthesis of lea proteins; and seeds harvested at R7 stage present physiological quality and lea protein pattern similar to the ones of filed dried seeds up to 14% of water content.