Effects of Summer Pruning on the Photosynthetic Activity of Current Shoots and the Translocation and Distribution of 13C-Photosynthates in Hedgerow-Trained Sweet Cherry Trees

Abstract

The purpose of this study was to examine the effects of summer pruning on the improvement and uniformity of the quality of fruit hedgerow-trained sweet cherry trees. The photosynthetic activity and translocation and distribution of photosynthates before summer pruning were compared with those after summer pruning to identify changes. Photosynthetic activity was measured in the basal part of current shoots 30 days after summer pruning. Photosynthetic activity did not change in response to weak sunlight, but it responded to changes in the photoenvironment to a 32% increase of strong sunlight from the level before summer pruning. The amount of 13 C translocation to fruit from various parts of the current shoots was in the following descending order: basal part > middle part > tip. The basal part provided the largest amount of 13 C translocation to fruit.Summer pruning further increased the rate of translocation to fruit from leaves in the basal part of current shoots. These data clearly show that current shoot management by summer pruning is an effective method to produce mass in sweet cherry.Key Words：assimilation, current shoot, matter production, palmette training