Qualidade fisiológica e expressão de proteínas em sementes de Handroanthus serratifolia submetidas à secagem

Abstract

The yellow-ipe seeds are considered orthodox, and have some mechanisms that assist in desiccation tolerance, like heat-resistant proteins and the presence of protective systems against free radical production. For investigate the drying effect on the quality of yellow-ipe seeds collected with 28% water content was used two methods: slow drying (30 °C) and fast drying (45 °C) until water contents equal to 20%, 15%, 10% and 5%. Seed quality was assessed by germination test, speed germination, emergence, speed emergence, T50 and water content. It was assessed the heat-resistant proteins expression and catalase enzymes (CAT), esterase (EST) and isocitrate lyase. The expression genes sHSP17.5, CAT3 and ICL6 were quantified by PCR technique in real time. Both, the slow and fast drying were effective for the water content reduction, and less time spent in fast drying. Higher values of germination and vigor were obtained in seeds with a water content of 20%, subjected to fast drying. Both, the slow and fast drying, there was induction of protein expression resistant to heat. There was variation in the electrophoretic pattern of the catalase enzymes, esterase and isocitrate lyase in seeds subjected to different treatments. The proteins expression in yellow-ipe seeds varies depending on methods of drying and water content of seeds. The drying of yellow-ipe seeds until the water content between 15 and 10% compromises the physiological quality of them.