Variation of glutamate decarboxylase activity and gamma-amino butyric acid content of wheat embryos during ripening of seeds.

GAD activity and gamma-ABA content of wheat embryos at 7 ripening stages were verified with the aim of studying the metabolic activity of embryo during dehydration and quiescence of caryopsis. Data showed that in the early stage of ripening GAD activity is very low, increases rapidly at dough-stage, remaining constant up to waxy-stage, and decreases in the last fully-ripe embryos. gamma-ABA content appears to be roughly parallel to the variations of GAD activity.