Formação de sementes de soja: aspectos físicos, fisiológicos e bioquímicos

Abstract

Formation of soybean seeds: physical, physiological and biochemical aspects This experiment aimed at the evaluation of the physical, physiological and biochemical changes during formation of soy seeds, produced in 2009 and 2010, in Piracicaba, São Paulo. Seeds of two cultivars of soy were used, namely CD-202 and CD-224, and treatments were composed by the moment of harvest, along the process of formation of seeds, and by the use or non-use of artificial drying. For the evaluations, we determined the number of days for seedling emergency, flowering, full flowering, harvest, physical parameters (productivity, rate of water in the seeds and mass of a thousand seeds) physiological parameters (viability and vigor) and biochemical parameters (rate of oil, of protein, of chlorophyll, of lignin and carbohydrates). The experimental delineation in use was in random blocks, in which each block contained one experimental unit of each cultivar, distributed at random, in a factorial scheme of eleven (harvesting periods), x two (dried and not dried), at four repetitions, and the statistical analysis were performed with software R. It was possible to conclude that at physiological maturity of soy seeds, stage R7, independently of the cultivar and of the evaluation of dry or humid seeds, the productivity, viability and rates of lignin are at their maximum; In the moment of harvest of soy seeds, stage R9, independently of the cultivar and evaluation of humid or dry seeds, the accumulation of mass is at its maximum, there is a drop in the level of water, of the viability and vigor, and the seed contains more oil and protein; The vigor of the seeds is at its maximum at stage R7 for the seeds which were evaluated dry and at stage R8 for the ones evaluated as humid, independently of the cultivar; There is the complete deterioration of the chlorophyll at stages R7, for the seeds of cultivar CD-202 and R8, for the seeds of cultivar CD-224; There are carotenoids in all stages of development of soy seed, however there are more of them in the beginning of the process of formation of seeds. There is variation of quantity of carbohydrates according to the evaluation of humid or dry seeds.

Qualidade de sementes de pimenta jalapenho em função da maturação e tempo de permanência nos frutos

“…Com a completa maturação e organização do sistema de membranas da semente, os valores de condutividade elétrica decresceram, indicando aumento de vigor. Este mesmo comportamento foi observado em sementes de soja, por Trzeciak (2012).…”

Canonical correlations between agronomic traits and seed physiological quality in segregating soybean populations

“…Several studies have reported a loss of seed quality when the seeds are exposed to adverse conditions of relative humidity and temperature during the process of maturation and after the point of physiological maturity. In this respect, under the conditions encountered in Brazil where high temperature and excessive rainfall predominate during soybean maturation, precocity should be highlighted as an escape mechanism in response to adverse environmental conditions (Trzeciak, 2012).…”

Avaliação dos teores de proteína total e extrato etéreo de grãos de variedades de soja provenientes de diferentes locais de produção

“…Segundo relatado por Hanson (1991) e Pípolo (2002), há uma correlação negativa entre os níveis de óleo e proteínas nos grãos, explicado pela concorrência dessas duas vertentes pelos esqueletos carbônicos. No entanto, a produtividade é positivamente correlacionada com o teor de óleo (Burton, 1987;Trzeciak, 2012).…”