Effects of Fruiting on Amylase Activity and Ribulose Bisphosphate Carboxylase-Oxygenase Content in Peach Leaves.

Amylase activity and ribulose bisphosphate carboxylase-oxygenase (RuBisCO) content in the leaves and leaf characteristics of peach trees (Prunus persica (L.) Batsch cv. Hakuto) having different crop load were investigated. The measurements was carried out about one week before fruit harvest. The RuBisCO protein content in the leaves was measured by subjecting sample tissue to electrophoresis on a sodium dodecyl sulfate (SDS-PAGE) gel and subsequent immunoblotting using the monospecific antibodies against spinach enzyme.The leaves of bearing trees were thinner, flatter, and greener compared with those of the non-bearing controls. The chlorophyll content per unit leaf area became more concentrated with increasing number of fruits per tree but the specific leaf weight (SLW, the dry weight per unit leaf area) decreased. Leaf amylase activity was higher on trees maturing 57 fruits; it was lowest in leaves of the non-bearing trees. Moreover, amylase activity was inversely proportional to the starch content in the leaves. RuBisCO protein content and the chloroplast compartments were larger in heavily cropped trees possibly due to their lower starch accumulation.