Senescence Patterns of Several Physiological and Biochemical Parameters of Field Grown Flag Leaves of Triticum aestivum L. cv Kolibri

Abstract

Several physiological and biochemical parameters of flag leaves of wheat grown in experimental fields under Mediterranean climate were studied for two consecutive years from anthesis through senescence. The first events observed were the decline in RuBP-carboxylase activity and the soluble protein content. Approximately 20 days after anthesis a marked decline begun in chlorophyll content and specific activity of RuBP-Case on protein basis. At the same time, phosphorus content declined sharply, the specific leaf weight (SLW) achieved its maximum value and CO2 compensation points at 21 % at 2.5 % oxygen increased rapidly. We suggest that these events indicate the onset of an irreversible state of senescence. The role of phosphorus content of the leaves at the final stages of senescence is pointed out, as also the incidence of the environment on the magnitude of the parameters studied.