Changes of leaves in autumn

In autumn, most leaves will dry and turn yellow, and then wither and fall.

In autumn, the temperature drops and the light time is shortened, which affects the absorption capacity of roots and the photosynthesis of leaves and cannot meet the growth and development of trees.

When the temperature drops and the air is dry, the water in the leaves evaporates quickly, but the ability of the roots to absorb water has been greatly reduced, and the supply of water and nutrients is insufficient.

For the survival of the tree, an isolation layer is formed at the petiole and the joint of the petiole, and the water supply to the leaves is interrupted. Coupled with the low temperature, chlorophyll is destroyed and lutein becomes active, so the leaves turn from green to yellow and fall off, and return to the earth with the autumn wind.

In fact, lutein that turns leaves yellow and lycopene that turns leaves orange and red exist in the leaves on the day they grow, but are covered by green chlorophyll.