The Influence of Root Pruning on Water Relations, Net Photosynthesis, and Growth of Young ‘Golden Delicious’ Apple Trees

Abstract

Young ‘Golden Delicious’/M7 trees were root pruned on 2 sides at 2.5, 5.0, and 10.0 cm distances from the stem which removed 10%, 28%, or 59% of their roots. Net photosynthesis (Pn) was reduced 35% and 47% and transpiration (Tr) 29% and 45% one day after root pruning of 28% and 59%, respectively, and recovery began 10 days later. Root pruning reduced leaf water potential significantly for 6 hr; recovery was apparent after one day. Root pruning severity of 10% had no effect on Pn, Tr, or water potential. Shoot growth rates decreased with increasing root pruning severity. The greatest reduction of shoot extension occurred during the 2nd and 3rd week following root pruning, with increasing growth rates observed in the 4th week. Suppression of shoot diameter increase lasted for 2 weeks. Leaves that developed following 28% or 59% root pruning were smaller than leaves of unpruned trees and had increased specific leaf weights (SLW), while previously expanded leaves were not affected. As root pruning severity increased, fresh weight of leaves and current shoots were reduced 45%; older parts of the tree were not influenced. Four weeks after root pruning there was no difference in total fresh weight of roots. The distribution of small roots from root pruned trees was increased in close proximity to the stem and decreased at distances greater than 5 cm from the stem.

Influence of Leaf Removal, Root Pruning, and Soil Addition on the Growth of Greenhouse-grown Strawberry Plants

“…Studies directly comparing removal of equivalent amounts of root and leaf/shoot tissue are not available in the literature. However, in separate studies of summer-pruning and root-pruning young apple trees, removal of 50% of the shoot resulted in a 44% reduction in total dry weight (11), while removal of 59% of the root system resulted in only a 25% reduction in total dry weight (2). These findings support our observation with strawberry that defoliation causes a greater reduction in growth than root pruning.…”

“…Carrot inflorescences form a terminal primary umbel, followed by lateral branching to produce secondary, tertiary, and higher orders of umbels. This indeterminate habit and prolonged flowering period results in varying seed maturities on different umbel orders when the entire crop is harvested at once (2,5,11). Consequently, the quality of seeds decreases as the umbel order increases (2,5,11,13).…”

“…This indeterminate habit and prolonged flowering period results in varying seed maturities on different umbel orders when the entire crop is harvested at once (2,5,11). Consequently, the quality of seeds decreases as the umbel order increases (2,5,11,13). However, the majority of the seed yield is produced on the numerous secondary umbels (4,13).…”

Effects of Root Pruning at Four Levels of Severity on Growth and Yield of ‘Melrose’/M.26 Apple Trees

“…Storage roots customarily are immersed in a fungicide or surface sterilant solution to prevent deterioration in the propagation bed (4). In a previous study, the surface sterilant calcium hypochlorite influenced neither the total number o f plants produced nor the deterioration of whole bedded storage roots of three cultivars and one unnamed clone (6), but calcium hypochlorite did encourage early plant production from three of these clones.…”

“…Most spur leaves are formed in the bud during the previous season, whereas the majority of shoot leaves are produced subsequent to bloom (7,8) and just after the root pruning in this experiment was applied. In greenhousegrown trees, root pruning had the greatest effect on growth in the first 4 weeks after treatment (6,16).…”