A poem describing dead leaves

The poem describing the dead leaves is as follows:

1, I didn't feel the dream of spring grass in the pond, and the leaves in front of the steps were already autumn.

2. Autumn wind gives birth to Lishui, and leaves fall all over Chang 'an.

3. Autumn wind rises in Bai Yunfei, plants and trees fall yellow, and geese return to the south.

4. The autumn wind is clear, the autumn moon is bright, and the fallen leaves gather and disperse, which surprised Western jackdaw in the west.

5, the autumn wind is bleak, the weather is cold, and the vegetation shakes the frost.

Situation and causes of defoliation:

The north of China lies in the north temperate zone. In autumn, due to the low temperature, the rainfall decreases, the absorption of plant roots decreases, and the water and inorganic salts obtained by plants are greatly reduced, so that physiological activities such as photosynthesis, respiration and transpiration cannot be carried out normally.

If leaves are left, a lot of water will transpiration, threatening the survival of plants. After cold and drought, new leaves will grow.

Whenever the drought or cold season comes, all the leaves die and fall off, leaving only branches, which are deciduous trees, such as peaches. After new leaves appear in spring and summer, the old leaves gradually fall off. As far as the whole tree is concerned, it is evergreen all year round and is an evergreen tree, such as Cinnamomum camphora.

After a certain period of physiological activities, a large number of metabolites, such as minerals, accumulate in cells, causing physiological function decline and death (chlorophyll destruction). When the weather gets cold, the soil temperature drops, the rainfall decreases, and the water provided by roots decreases, while deciduous leaves can reduce transpiration and water consumption, which is beneficial to the survival of plants in cold and dry seasons.

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 meaning of fallen leaves:

This is an adaptation of plants to reduce transpiration, keep water in their bodies and spend the cold and dry season. This habit is formed in the long-term evolution of plants.

The mechanism of defoliation is to adapt to unfavorable environment. 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.