The induction of sensitivity to gibberellin in aleurone tissue of developing wheat grains : I. The effect of dehydration.

Aleurone layers from immature developing wheat grains (Triticum aestivum L. cvs. Sappo. and Champlein), though normally insensitive, can be made to produce α-amylase in response to gibberellic acid by subjecting the grains to a period of enforced dehydration prior to introduction to the hormone. The change in sensitivity appears to depend upon the water content of the tissue, water levels of below approximately 25% being critical for the effect. Grain detachment or duration of drying apparently do not qualitatively influence the development of sensitivity to gibberellic acid. Enhanced sensitivity resulting from drying is not caused by changes in gibberellic acid uptake. A possible mechanism for the change in sensitivity of aleurone cells might be through structural alterations in cell membranes.