The effects of low water contents on physiological activities of seeds

Physiological activity changes in seeds when water content is changed from 0 to 40%. The limited metabolism of dry seeds allows for studies of the role of water in the biochemical reactions of living systems. At very low water contents, seeds exhibit limited biochemical activity, however light reactions and some oxidative processes are possible. As water content is increased, enzymatic reactions are increasingly facilitated. At moisture contents of about 24% mitochondrial electron transport is detectable. Changes in the physiological activity of seeds occur at discrete moisture levels that are reflective of discrete changes in the thermodynamic properties of water.