Glutamate dehydrogenase in the first leaf of wheat

The activity of glutamate dehydrogenase and the amounts of two antigens, bearing the bulk of this activity, were determined in wheat leaves (Triticum acstivum L. cv. Capitole) at different ages. These results were compared to those obtained with leaves deprived of light (darkness‐stressed) during three days, at different stages of leaf life. The glutamate dehydrogenase activity increased in the leaves during normal senescence of the whole plant. De novo synthesis of one of the glutamate dehydrogenase proteins was shown, which correlated with this, increase in activity. The considerable differences between She effects of darkness‐stress, according to the leaf age, may characterize three steps in the leaf life: a first step during which leaves were not affected by stress, a second one for which the stress effect was partially reversible, and a final one during which stress impact was irreversible.