during development and drying, a number of protection mechanisms act on the maintenance of seed physiological quality. some of these mechanisms maintain the integrity of the cells, which is fundamental to the perfect functioning of cell metabolism. the study of the ultra-structure enables visualization of damage caused by drying in the absence of protection mechanisms. in this research, damage occurred during the soybean seed development and drying was studied by means of scanning electron microscopy (sem). in addition, seeds were also evaluated regarding the physiological quality. thus, seeds in different developmental stages were collected and submitted to different drying temperatures and treatments. evaluations were made concerning the seed physiological quality by means of the germination test, cold test, emergence test under controlled conditions and electrical conductivity test. the damages were visualized by means of scanning electron microscopy utilizing the leo evo40 microscope. the results showed that the soybean seeds become desiccation tolerant when they possess around 30% water content. drying of seeds with moisture content above 30% caused reduction in cellular volume, disorganization of the cell walls and decrease in seed physiological quality. higher germination values were observed in seeds with 30% moisture content in the field, whereas higher values of vigor were observed in seeds with 40% of moisture content in the field.