Changes in Chemical Composition of Regrowing Leaves of Orchard Grass

Abstract

Regrowing process and changes in chlorophyll, nitrogen fractions, phosphate fractions and carbohydrate fractions concerning photosynthesis in the leaves were measured on orchard grass during 3 week regrowth periods after cutting. In the early stage of regrowth, most of the new tissues regrown were dependent on the expansion of the cut-leaves which had been expanding in the lower leaf sheaths. The acquirement of photosynthetic activity on their cut-leaves contributes much to the physiological recovery of the plant after cutting. The chlorophyll concentrations in cut-leaves increased immediately after cutting and attaind to the maximum on 12th days and decreased slowly after that. TCA-insoluble nitrogen did not change so much for first 5 days after cutting and went up the maximum concentration on 9th day and decreased after that. Consequently, the ratio of chlorophyll to TCA-insoluble nitrogen cotents revealed a loose slope in curve at the phase of 5th to 7th day and on and after 15th day. These were suggest that the former impressed the time when a steep accumulation of leaf protein was caused by greening of cut-leaves which grew out from lower leaf sheaths, the latter when the decrease of leaf protein, on whole plant, appeared to be caused by the senescence of the regrowing leaves. The concentration of TCA-soluble phosphate and soluble carbohydrates, especially 85% ethanol soluble fraction, changed similarly in that of the chlorophyll and TCA-insoluble nitrogen.