Chages in Carbohydrate and Ribulose Bisphosphate Carboxylase-Oxygenase Contents in Peach Leaves after Applications of Different Amounts of Nitrogen Fertilizer

Abstract

The effects of applying different amounts of nitrogen on the accumulation of nonstructural carbohydrate and ribulose bisphosphate carboxylase-oxygenase (RuBisCO) and on some characteristics of peach leaves were determined on young trees. The leaf nitrogen contents of trees supplied 0 and 1.5g N/pot (N-0 and N-1.5, respectively) were lower than were those administered 9.0g/pot (N-9). On a dry weight (DW) basis, leaves sampled from N-0 trees and N-9 trees were 1.8% and 4.0%, respectively. The chlorophyll content per unit leaf area increased with increased nitrogen applied. The starch content on a dry weight basis was inversely proportional to the amount of nitrogen administered, whereas total soluble sugar per unit dry weight was proportional. The sorbitol and sucrose contents per unit leaf fresh weight were the lowest in leaves from N-0 trees. The RuBisCO content detected by immunoblotting after SDS-polyacrylamide gel electrophoresis as well as by immunostaining of sections under the light microscope increased with the increase in the amounts of nitrogen applied.