Anthocyanin is the main pigment that forms plant color, and its synthesis must be induced by light. The stronger the light, the more anthocyanins accumulate. Blue light and ultraviolet light are the most effective light quality to promote anthocyanin synthesis. The intensity, quality and time of light affect the color development of colored plants by affecting the synthesis of anthocyanins and regulating the activities of anthocyanin-related enzymes. Some plant species, such as Ligustrum lucidum, Berberis purpurea, etc. The stronger the light, the brighter the color of the leaves. But some indoor ornamental plants, such as peacock arrowroot, will show colorful colors only under weak scattered light.
The synthesis of anthocyanins in marigold leaves is related to strong light, low temperature and high radiation. The experiment shows that temperature obviously affects the content of anthocyanins in leaves. The color of Cotinus coggygria in Beijing is not as bright as that in southern Henan, which may be due to the small temperature difference between day and night in the south, which is not conducive to the accumulation of sugar and the consumption of anthocyanins. Chlorophyll has poor adaptability to temperature. In autumn, with the decrease of temperature, chlorophyll is first decomposed, and the synthesis of new chlorophyll is also limited, and the original carotenoids in leaves are displayed, which makes the leaves turn yellow or red. At the same time, due to the large temperature difference in autumn, it is beneficial to the accumulation of sugar in leaves, and then promote the synthesis of anthocyanins; With the decrease of rainfall, the concentration of anthocyanins increased, and the original leaves of plants were red or orange-red.
Viruses can cause mosaic in plants, such as mosaic virus parasitic in cauliflower. Tobacco mosaic virus (TMV) can infect more than 200 kinds of plants, causing plants to produce irregular spots. Sometimes, although the leaves are still green, the veins will turn yellow, white or red. But as long as the virus does not affect the growth and development of plants, it will not only do no harm, but also make the leaves more beautiful. So some people use virus breeding to make plants more colorful. Due to the great difference between the introduction places and the introduction places of color-leafed plants, the leaves of some gold-leafed and purple-leafed plants may turn green, such as cedar with golden leaves, Populus mosaic, Taxus chinensis with golden leaves, etc., mainly because these color-leafed plants are caused by viruses and turn green after being healthy.
The lack of plant nutrients will lead to the change of plant leaf color. For example, when the soil is short of nitrogen, the petiole and leaf base are red, mainly because chlorophyll synthesis decreases and carotenoid color appears; When phosphorus is deficient, the leaves are dark green with brown spots and the old leaves are red; When potassium is deficient, the leaf margin is brown; Under sulfur deficiency, the leaves are yellow-green, white and blue; When calcium is deficient, the leaves have reddish-brown spots, which first appear between the veins; When magnesium is deficient, the leaves have spots, starting from the center of the leaves. The above changes in leaf color are caused by malnutrition, which is short-lived, and the leaf color can be restored after proper nutrition is supplemented.
People often regret that it is too short to enjoy the red leaves in Xiangshan. Knowing the mystery of colorful plants, people no longer have to regret it. Now, we can make red leaves appear every day, even yellow leaves, purple leaves, two-color leaves and three-color leaves appear at will when and where we need them.