The annual growth cycle of deciduous fruit trees and deciduous ornamental trees is obviously divided into growth period and dormancy period; Evergreen trees have no obvious dormancy period in the annual growth cycle. 1 Annual plants only have a growing period. In the meantime, some 2-year-old plants have obvious dormancy period, while others do not. Taking perennial woody plants as an example, the characteristics of annual growth cycle of horticultural plants were expounded.
(1) growth period
Growth period refers to the period when all parts of plants show obvious morphological characteristics and physiological functions. Deciduous trees germinate in spring and shed their leaves in autumn. It mainly includes germination, vegetative growth, flowering and fruit setting, fruit development and maturity, flower bud differentiation and defoliation. However, the flowering, vegetative growth, flower bud differentiation and fruit development of evergreen trees can be carried out at the same time. The old leaves often fall off after the new leaves are unfolded, and the new shoots can germinate many times in 1 year. Some trees can differentiate flower buds many times, blossom and bear fruit many times, and their phenology is complicated. Nevertheless, the order of the one-year growth cycle of the same plant is basically unchanged, and the occurrence of each phenological period changes sooner or later due to the influence of climatic conditions, especially temperature.
(2) dormant period
Dormancy refers to the period when the life activities of buds, seeds or other organs of plants are weak and the growth and development performance are stagnant. The dormant organs of plants are mainly seeds and buds. Such as apples, peaches, chestnuts and peonies. It is necessary to stratify at low temperature to reduce the substances in seed coat and endosperm that inhibit germination before germination. Dormancy of buds includes dormancy of deciduous trees during overwintering, and dormancy of bulbs and tubers of garlic and potatoes.
(1) Dormancy period of deciduous fruit trees: The dormancy period of deciduous fruit trees usually refers to a period from defoliation in autumn to germination in the following spring. The length of dormancy period varies with tree species, varieties, production environment and local natural climate conditions. Generally speaking, plants growing in cold regions have a long dormant period and need low temperature. Among the local climatic conditions, temperature has the greatest influence, which directly affects the length of dormancy period. Generally, the lower the temperature, the shorter the sleep time; The higher the temperature, the longer the sleep time. The low temperature required for deciduous trees is generally 0.6-4.4℃.
(2) Dormancy of tubers and bulbs: The dormancy of potatoes actually begins from the moment the tubers begin to swell, but the dormancy period is calculated according to the number of days from harvest to bud germination, which belongs to natural dormancy and can be dormant for 1-3 months at a temperature of about 25℃. After the natural dormancy is over, it is still necessary to continue forced dormancy at 0-4℃ before sowing. Dormancy of onion, garlic and so on. Similar to potatoes.
③ Dormancy of evergreen fruit trees and ornamental trees. Evergreen woody plants generally have no obvious natural dormancy, but when the external environment changes, such as low temperature, high temperature, drought, etc., they can also temporarily hibernate. , make the trees into a state of forced dormancy. Once the harsh environment is lifted, it can quickly resume growth.