THE REGULATION OF ROOT PRUNING AND SOIL WATER CONTENT AFFECTS APPLE LEAF WATER USE EFFICIENCY
The effect of root pruning and soil water content on the leaf water use efficiency (WUE) in pot-cultured three-year old apple trees (Malus pumila Mill grafted onto Malus hupenensis Rhed.) was studied. The results show that root pruning increased WUE significantly and that the WUE increased step by step from day 2 to day 42 after treatment. At the same time, transpiration rate (Tr) and stomatal conductance (Gs) decreased, but net photosynthetic rate (Pn) and carboxylation efficiency (CE) recovered rapidly and were higher than those in the controls after day 21 following treatment; the concentration of zeatin riboside (ZR) in leaves returned to the control levels 28 days after treatment. When relative soil water content (RSWC) approached 50%, WUE was the greatest. The decrease of stomatal conductance was similar to the increase of WUE when RSWC decreased from 75% to 55%; the change of carboxylation efficiency was similar to WUE when RSWC decreased from 50% to 20%. WUE decreased on the day of waterlogging, but it increased again and reached the control level on the third day after waterlogging. After 6 days, the WUE decreased gradually with the extension of waterlogging time.
Yuling Jie, , Hongqiang Yang, , Lianzhong Zhang, and Xinsuo Luo, (2008). THE REGULATION OF ROOT PRUNING AND SOIL WATER CONTENT AFFECTS APPLE LEAF WATER USE EFFICIENCY. Acta Hortic. 767, 345-350
root pruning, soil water content, water use efficiency, apple