Estudos fisiológicos e proteômicos relacionados à dessecação de sementes de café durante o armazenamento

Abstract

Understanding the physiology of Coffea arabica seeds during desiccation and during storage is of great importance, since seed production and quality influence the vigor of seedlings used for the formation of crops. The objective was to evaluate the physiological quality and the expression of proteins possibly related to the desiccation tolerance in Coffea arabica seeds submitted to drying and storage. Seeds of Coffea arabica L. of the cultivar Catuaí Amarelo (IAC 62) were grown at the Bom Jardim farm located in Bom Sucesso, Minas Gerais. The fruits were harvested at the stage of cherry ripening, peeled and the seeds went through the process of natural degumming (without chemicals). Seeds were dried to 40%, 20% and 10% water and then stored for 60, 120 and 180 days in a cold room (10 ± 2 ° C and 70% RH). Seeds with 46% water content and without storage as control treatment were used. The physiological quality of the seeds was evaluated by first germination test, germination test, normal seedling at 30 days of sowing test, cotyledonary leaves expanded at 45 days of sowing test, emergence test and rate of emergence (IVE). Expressions of the enzymes superoxide deaminase (SOD), catalase (CAT), peroxidase type III (PO), ascorbate peroxidase (APX), esterase (EST) and alcohol dehydrogenase (ADH) were also evaluated by electrophoresis and spectrophotometry the expression of heat-resistant proteins by the electrophoresis technique. The evaluations were done before the storage of the seeds and after 60, 120 and 180 days. In general, seed vigor was observed at all storage times when dried at 40% water content and less vigor in seeds dried at 10% water content. Reduction of the expression of antioxidant complex enzymes in seeds with 40% water content and increase in seeds dried at 20% and 10% water content during storage was verified. This was also observed for the EST and ADH enzymes. As for the heat-resistant proteins, it was found that from the 60 days of storage the expression differed in seeds dried at 40% water content during the storage the expression of these proteins were reduced. It can be concluded that water content and storage influence the physiological quality of Coffea arabica seeds and that seeds dried at 40% water content have a lower loss of viability during storage. The higher expression of enzymes in the antioxidant system and the EST and ADH enzymes are associated with lower physiological seed quality and can be correlated with desiccation intolerance. Expression of the heat-resistant proteins reduces in the course of storage.