Dry seeds exist generally in a glassy (or vitrified) state. The high viscosity of the glassy state would be expected to have a retarding effect on deteriorative reactions in the cytoplasm. Thus the glassy state may be considered to be a biophysical barrier for seed deterioration. The present study aims to test the hypothesis that seed storage stability is associated with the glassy state. With the equations derived from the seed viability equation, we have calculated the maximum temperature (Tmax) for long-term storage of corn, pea and soybeans. The Tmax for long-term seed storage is found to be in a good agreement with the glass transition temperature (Tg) in each instance, suggesting that seed deterioration would be accelerated when seeds are not in the glassy state. Experiments with soybeans given accelerated ageing show that the loss of glassy state is followed by a rapid decrease in seed viability. These observations provide indirect evidence that the glassy state may play a significant role in seed storage stability. Copyright 1994, 1999 Academic Press