Plastic pruning can improve the metabolism of the tree and improve the nutrition of the tree. The storage nutrients in the fruit trees are basically carbohydrates and nitrogenous substances, and their contents and proportions have a great influence on the growth and results of the trees. According to the experiment, the fruit trees were pruned. After 2 weeks, it was found that the nitrogen and water contents in the pruning tissues were much higher than those in the untrimmed, and the starch and sugar content in the pruned branches were lower than the control. This suggests that pruning alters the nutrient composition of the fruit twigs, which favors flower bud formation and increases early yield.

Correct use of pruning techniques, especially for large trees during the fruiting period, can significantly improve the light conditions and increase the photosynthetic efficiency of the leaves, especially the nutrient status of the canopy leaves in the canopy; the weak trees with more flowers Cutting off some flower buds can reduce nutrient consumption and increase the accumulation of nutrients in the whole tree, which is also beneficial to increase the leaf area and total root amount of the whole tree, and promote the growth and development of the whole tree.

The summer pruning of fruit trees also has a significant impact on the nutrient content of the shoots. According to experiments, both ring stripping and twisting can increase the accumulation of organic nutrients at the apex of the shoots, and promote the transformation of the carbon and nitrogen ratio in the tree to the direction favorable for the formation of flower buds, thus promoting the flowering results of summer cut branches.

Perennial fruit trees, the tree has accumulated a large amount of storage nutrients. During the pruning process, sparse or shrinking branches will undoubtedly take away some storage nutrients. Therefore, the degree of pruning should be limited to the minimum, cut off. The part is preferably the undeveloped part of the storage organization. Therefore, we should make maximum use of summer and autumn pruning to minimize the amount of winter pruning, and the time of winter pruning is best arranged after the tree nutrient reflux.

Topping or short-cutting, because the apex of the branches is cut off, temporarily reduces the synthesis and supply of endogenous hormones, and reduces or eliminates the inhibitory effect of hormones on the lateral buds, so it is beneficial to the germination of lateral buds. The earlier the heart is picked in summer, the greater the secondary growth. Pre-flowering and flowering topping can significantly improve fruit setting.

Ring stripping or ring cutting on the top of the bud eye cuts off the channel through which the hormone is transported downward, which can significantly inhibit growth and promote germination and flower bud differentiation.

The auxin content in the erect branches, horizontal branches and drooping branches decreased in turn, so that the downward buds were not easy to germinate, while the buds on the back were easy to be plucked. During the pruning process, the transport and distribution of hormones can also be affected by pulling, bending or twisting. After the light conditions are improved by pruning, the transport rate of hormones is also accelerated.

Pruning can also increase the activity of the enzyme and produce catalase, and the production of catalase can eliminate the damage of hydrogen peroxide to the tree caused by the metabolism, thereby improving the metabolism of the fruit tree.