Why do maple leaves turn red?

The greatest influence of maple leaves is that they turn red. Writers of all ages favor maple leaves, and it is common to sing poems and describe them, such as the Tang poet du Mu's "parking only because they love the maple forest in the evening, and the frosted maple leaves are more red than the flowers of February." And so on, the beauty of maple has been recognized by people throughout the ages, and maple trees cultivated in local landscapes are also more common. Let's take a look at why maple leaves turn red.

When does the maple leaf turn red?

Maple leaves turn red in autumn. Maple leaves are in autumn, because the temperature drops, causing the green pigment of maple leaves to turn red. In northern China, autumn is from August to October, and the real entry of autumn is not until September, so maple leaves are generally not red until September and October. It gets cold later in southern China, and the maple leaves turn red later.

When does the maple fall its leaves?

Maple leaves fall in autumn. When autumn comes, the day is shortened and the night is prolonged, the weather becomes cold, the soil temperature decreases, Rain Water decreases, the root water absorption capacity is greatly weakened, but the transpiration intensity is not weakened, and the lack of water causes defoliation. At the same time, after a certain period of physiological activities, a large number of intracellular metabolites, such as mineral accumulation, lead to the decline of physiological function and death (chlorophyll destruction).

Why do maple leaves turn red?

1. Stress response: the redness of maple leaves is actually the result of maple trees' response to the pressure of nature. Red actually acts as a sunscreen, making the leaves stay on the tree longer, so that the tree can absorb more nutrients. The study found that the pressure of nutrition, especially the pressure of nitrogen deficiency, makes maple leaves red earlier and more thoroughly.

2. Internal factors: the red color of leaves mainly depends on two kinds of substances, one is carotene, which is commonly found in chloroplasts. The other is anthocyanin, which exists in the cell fluid in the vacuole. When the cell fluid is alkaline, the anthocyanin is blue-purple, and when the cell fluid is acidic, the anthocyanin is red. After the beginning of autumn, the anthocyanins in the leaves of Codonopsis lanceolata increased, and the drop in temperature made the destruction of chlorophyll disappear, so the green leaves became red leaves.

3. External factors: when the temperature drops rapidly to a certain extent, and the temperature at night is much lower than that during the day, the leaves have not withered, but most of the chlorophyll has been destroyed, and at the same time, the increase of temperature difference between day and night also contributes to the formation of anthocyanins, so the leaves turn red quickly. If the temperature drops slowly, and the temperature difference between day and night is small, the chlorophyll has not been destroyed and the tree has withered, it will not become beautiful red leaves.