THE STABILITY OF WHEAT EMBRYO GLUTAMATE DECARBOXYLASE UNDER CONDITIONS OF WATER STRESS

Abstract

The effect of various treatments on the stability of glutamate decarboxylase in wheat seedlings and wheat embryos was investigated in an effort to obtain information suggesting a molecular basis for desiccation resistance in plants. The decarboxylase activities of germinating wheat grains before and after desiccation were measured. Attempts were made to relate activity of the enzyme to a soluble or particulate cell fraction by differential centrifugation. The responses to desiccation by active protein preparations following defatting treatments with n-butanol were measured. The decarboxylase activity of germinating wheat increased for 54 h and the stability of the enzyme decreased during this time. Particulate cell fractions were devoid of activity. The responses of the extracted enzyme to desiccation suggest that its stability may reside in a capacity for dissociation into smaller protein components, under conditions of water stress, and that this capacity may depend upon the presence of lipids.