CHLOROPHYLLASE ACTIVITY IN WHEAT, TRITICUM-AESTIVUM L. LEAVES DURING DROUGHT AND ITS DEPENDENCE ON THE NITROGEN ION FORM APPLIED

Wheat plants grown on vermiculite and treated with nutrient solutions containing either NO3- or NH4+ form of nitrogen, were subjected to slo w developing drought. During the drought, leaf water potential, chloro phyll content and chlorophyllase activity were monitored. The results indicate that with the decreasing water potential there occur changes both in chlorophyll content and chlorophyllase activity. These changes are dependent on the type of nitrogen ion applied. Comparing chloroph yll content changes with chlorophyllase activity changes in both N tre atments we conclude that chlorophyllase may not have only hydrolytic f unction under drought conditions. (C) 1997 Elsevier Science Ireland Lt d.