We often hear the word "Periodicity" in our daily life. Do you know that there is periodicity in plants? Did you know that the periodicity of plants is also classified? Pro, let's go and learn!
Seasonal plant -- sparrow
Seasonal periodicity of plants: the growth of annuals and perennials shows more or less obvious seasonal changes. For example, annual crops are sown in spring, grown in summer, harvested in autumn and stored in winter, and perennial trees sprout in spring, grow vigorously in summer, stop growing in autumn and hibernate in winter.
It goes on and on, year after year. The growth of plants in a year with the change of seasons and the regular changes, called seasonal periodicity. It is mainly affected by the temperature, moisture, sunshine and other factors in the four seasons, and is controlled by internal factors. In spring, the sunshine duration and temperature rise, the water content of tissue increases, the protoplasm changes from gel state to sol state, auxin, gibberellin and cytokinin are transformed from bound state to free state, and all kinds of physiological and metabolic activities are greatly strengthened. Adorable seeds of annual crops or perennial woody plants germinate and begin to grow. In summer, the light and temperature extend further. When the plant grows and rises, its water supply is usually sufficient, so the plant grows vigorously and begins to breed reproductive organs on the vegetative organs. With the coming of autumn, the sunshine is shortened obviously, the temperature begins to drop, and various physiological metabolic changes are taken place in the body, which are opposite to those in spring. Abscisic acid and ethylene are gradually increased, and organic matter is transferred from leaves to reproductive organs or roots, stems and buds, and leaves and leaves fall The results showed that the seeds of annual plants began to dormant after mature, the vegetative bodies died, and the buds of perennial woody plants began to dormant; the metabolic activities of plants decreased to a very low level with the coming of winter, and the dormancy gradually deepened. The seasonal periodicity of plant growth is the active adaptation of plants to relatively stable seasonal changes in the long-term historical development.
Seasonal plant -- the diurnal periodicity of Lilium plants. The growth rate of plants changes regularly according to the diurnal variation, which is the circadian periodicity. The main factors affecting the plant growth are temperature, water and light. In the course of a day, because the light intensity and temperature of day and night are different, the water content in the body is also different, so the growth of plants shows the periodicity of day and night. For example, stem elongation, leaf enlargement and fruit enlargement all have this characteristic. Whether plants grow fast in the daytime or at night depends on the limit of the lowest among various factors.
It can be seen from the periodic change of maize plant growth day and night that the growth rate is closely related to temperature without water shortage, and the plant grows faster in warm day than in cold night. The effect of sunlight on plant growth is mainly through increasing air temperature and transpiration rate to affect plant growth. At noon, proper water deficit reduced the growth rate. Therefore, the growth rate of maize presents two peaks in a day. However, in the case of insufficient water, transpiration is large in the daytime, and the growth of plants is inhibited by light, so the growth will be slower, but faster at night. The periodic change of day and night depends largely on the periodic change of environmental conditions.
Maize plant