The Study On The Reason Of Heavily Pruned Longan Trees Difficult To Flower And The Technique To Promot It Off-Season Flowering

Heavily retractive pruning was carried out on the longan trees (Dimocarpus longan Lour. cv. Shixia) which intersected each other. The trees were pruned bock to a average height of 1.33m from 3.29m～3.62m. PP₃₃₃ was applied to adjust growth of treated trees one month before pruning and KClO₃ was applied to promote off-season flowering affter 4 times shoot have growed. The photosynthesis, mineral nutritions, organic nutritions and endogenous hormone contents were tested after implementing heavily retractive pruning. The results showed as follows:1.The effect on shoot growth The shoots of Shixia longan trees which been implemented heavily retractive pruning obviously excessivly growed, the diameter of shoots and the leaf area all remarkably increases, along with the number of shoot times increase, the excessive growth weakens; Apply PP₃₃₃ to be able to suppress the excessive growth of branch, the suppression effect reduces along with shoot times increase.2. The effect on CHL and photosynthesis Heavily retractive pruning and PP₃₃₃ applying do not have remarkable influence to the CHL content and the photosynthesis of Shjia longan leaves, KClO₃ applying enhanced the CHL content and the photosynthesis intensity of longan leaves during the physiological differentiation time.3. The effect on protein and soluble sugar Heavily retractive pruning reduced the soluble sugar content but had no remarkable influence to the protein content of the...