Why do maple leaves turn red in autumn?

Scientific experiments have proved that plant leaves not only contain chlorophyll, lutein, carotene and other pigments, but also contain a special pigment called anthocyanin, which is a "chameleon" and is red in acidic solution. With the change of seasons, the temperature and sunshine increase or decrease correspondingly, and the main pigment components in leaves also change. In autumn, the temperature drops and the light weakens, which is beneficial to the formation of anthocyanins, while the leaf cell sap of maple and other red-leaf trees is acidic, so the whole leaf is red. The big tree in front of us is a maple. Whenever autumn comes, its leaves turn red. I believe that when you go to Niumulin in autumn, you can also see the intoxicating scenery of "Frost leaves are redder than February flowers".

The reason why maple leaves turn red: Maple leaves turn red mainly because of two substances: one is carotene, which is a common orange-red pigment in chloroplasts, and the other is anthocyanin, which exists in the cytosol of vacuoles. When the cytosol is alkaline, anthocyanins are blue-purple, and when the cytosol is acidic, anthocyanins are red. Why the maple leaves turn red in autumn: Because after autumn, the anthocyanins in the maple leaves increase, and the temperature drop makes the destruction of chlorophyll disappear, so the green leaves turn into red leaves. ?

The external factor of discoloration is climatic conditions: when the temperature drops rapidly to a certain extent and the temperature is much lower at night than during the day, the leaves have not fallen, but the chlorophyll has been mostly destroyed. 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, the temperature difference between day and night is not big, chlorophyll is not destroyed, and the tree has withered, it will not become beautiful red leaves.

Maple leaves turn red mainly because of anthocyanins. The cold weather in autumn weakens the ability of leaves to transport nutrients. Glucose produced by photosynthesis in leaves can not be transported to leaves, but remains in leaves to become anthocyanins, and leaves gradually turn red. At the same time, due to the cold weather, chlorophyll in leaves is constantly decomposed, and green is weakened and replaced by red. Because anthocyanins turn red when they are acidic, only acidic leaves can turn red. Maple leaves, tallow leaves, maple leaves and persimmon leaves are all acidic leaves, so they all turn red in autumn.