1. Bud transformation: Bud transformation refers to the mutual transformation between leaf buds and flower buds. The leaf buds of fruit trees can be transformed into flower buds to blossom and bear fruit when the internal nutritional conditions and external environmental conditions are suitable. Similarly, when flower buds are stimulated by some special stimuli, their flower primordia can be destroyed and become leaf buds. This characteristic is often used in pruning to adjust the relationship between fruit tree growth and fruit bearing.
2. Self-withering of buds: Self-withering of buds, also known as self-cutting or self-thinning, refers to the characteristic that the terminal buds of new shoots are easy to die by themselves after the branches of some fruit trees exceed a certain age. The self-withering of buds is beneficial to reduce the formation of long and weak drooping branches and the natural regeneration of fruiting branches. Fruit trees such as hawthorn, persimmon, apricot and chestnut all have this characteristic.
3. Premature germination of buds: Premature germination of buds refers to the characteristics that buds mature rapidly after forming in the same year and can germinate when conditions are suitable. Pruning often takes advantage of the characteristics of early maturity and easy sprouting of young buds of fruit trees, and promotes secondary shoots many times a year to accelerate the cultivation of backbone branches, so as to make the crown form early, bear fruit early and yield early. The buds of peaches, grapes and other fruit trees all have this characteristic. There are also premature buds that remain dormant for a long time, and only after special stimulation can they grow long branches.
4. Latency of Late Maturity of Buds: Latency of Late Maturity of Buds refers to the characteristics that buds mature slowly after forming on new shoots and cannot germinate long branches in the same year. The late maturity of buds is beneficial to improve the development quality of branches and buds, make fruit trees overwinter safely, bear long branches year after year, and stabilize the growth quality and yield of trees. Especially those dormant buds that can't germinate for many years, even if they are mature, are in a latent state for a long time, which is beneficial to the natural regeneration and rejuvenation of branches, thus prolonging the life of trees.
5. Heterogeneity of buds: Heterogeneity of buds refers to the characteristics that buds in different parts of the same branch have obvious differences in development quality. The reason for this feature is that the nutritional status and environmental conditions of buds in different parts of the bud stage are different, which leads to the difference in quality. The regularity of heterogeneity is that the bud between the top bud and the spring shoot is a complete bud, the buds in the middle of the autumn shoot and above and below the spring shoot are semi-complete, the buds at the joint of the spring shoot and the autumn shoot are blind buds, and the buds at the base of the branches are flat buds.
Heterogeneity of Buds (Apple)
Therefore, many kinds of buds can be planted on the same branch at the same time, such as full bud, half full bud, blind bud and shriveled bud. There are obvious differences in growth position and development quality of these buds, and there are also obvious differences in pruning reaction after pruning. Generally speaking, full buds often have long branches, semi-full buds often have medium and long branches, and flat buds often have medium and short branches, so blind buds are difficult to branch. Experienced pruners always follow this principle and choose the most suitable pruning position on the branches according to the pruning requirements.
6. Germination ability of buds: refers to the germination ability of buds on annual branches under natural conditions or after cutting, which is generally expressed by germination rate. Germination rate refers to the percentage of germination in all buds. When the germination rate is high, it means strong germination, and when the germination rate is low, it means weak germination. So it is often said that the strength of germination is the level of germination rate. When pruning fruit trees, the specific pruning methods should be determined according to the germination rate of different tree species and varieties.
7. Bud-forming ability: Bud-forming ability refers to the ability of buds left after annual branches are cut off to grow branches. Many branches grow, indicating strong branches. On the other hand, there are few growing branches and many medium and short branches, which shows that the ability of branch formation is weak. Different kinds and varieties of fruit trees have different pruning methods because of their different branching abilities.