Why do some plants shed their leaves in spring?

Because it will grow new leaves in spring, some will bloom in spring, and some old leaves will affect its development if they are not cut, so it will shed leaves in spring, and there are more leaves. Deciduous trees shed their leaves in autumn. Evergreen trees shed their leaves and grow new leaves from time to time throughout the year. Everything wakes up in spring, which is the beginning of a new round of development cycle and a new round of leaves, so evergreen trees will lose more leaves in spring.

Ordinary evergreen trees will lose their leaves in spring, such as camphor trees with nasal spray. Evergreen plants shed their leaves in four seasons, but more in spring.

Extended data:

Why do leaves fall off? Why are the leaves so smooth after falling off?

The reason is that there is separation-some cells (originally calcium pectin, soluble pectin and pectin acid) at or near the base of petiole are produced due to changes in cell or biochemical properties.

The detachment zone includes: detachment layer and protective layer: cell division produces a group of small parenchyma cells. For delamination, the cell wall gelled and the cells began to swim. Due to the weak supporting force, the gravity of the leaves and the shaking of the wind, the leaves fall off from the abscission layer. Then several layers of cells below the abscission layer are embolized to form a protective layer on the cross section to avoid the loss of water and the invasion of pests and diseases.

The significance of defoliation is that plants reduce transpiration, keep water in their bodies, and survive the cold and cold.

An adaptation in dry season is formed by the long-term evolution of plants.

Mechanism of defoliation: defoliation can reduce transpiration and make plants survive in cold and dry seasons. This habit is formed in the long-term evolution of plants. Short sunshine accelerates the formation of abscission layer, and abscisic acid and ethylene increase, which can accelerate leaf abscission.

References:

Baidu encyclopedia-fallen leaves