Why are flowers so red?

first of all, it has its material basis. Whether it is safflower or red leaf, their cell fluid contains anthocyanins changed from glucose. When it is acidic, it appears red. The stronger the acidity, the redder the color. When it is alkaline, it appears blue, which is more alkaline and becomes blue-black, such as black chrysanthemum and black peony. And when it is neutral, it is purple. Colorful, red and blue meet, which are all displayed by anthocyanins in different acid-base reactions.

it also needs to be explained by physical principles. Sunlight will be divided into seven colors: red, orange, yellow, green, cyan, blue and purple after being refracted by a prism or water drops. The wavelength of these seven colors is different, the wavelength of red light and the wavelength of violet light are short. Acidic anthocyanins will reflect the long red light waves and send them to our eyes, and we will feel that they are bright red flowers. Similarly, neutral anthocyanins reflect purple light waves, alkaline anthocyanins reflect blue light waves, and carotene has different components, so it reflects yellow light waves or orange light waves respectively. White flowers contain no pigment, but the tissue contains air, which will reflect all the light waves. Some petals, with more tiny and neatly arranged glass balls on the surface, look like velvet, which can reflect light as strongly as diamonds, and the colors are more vivid, such as some Chinese rose flowers.

and its physiological needs. Different wavelengths of light contain different amounts of heat: red, orange and yellow wavelengths contain more heat; Blue and violet light have short waves and less heat. The tissues of flowers, especially petals, are generally tender. In the wild, red, orange and yellow flowers all grow in places with strong sunlight, reflecting long light waves containing a lot of heat, which will not cause burns and have a protective effect. Blue flowers grow under trees and grass, reflecting short light waves and absorbing weak long light waves with more heat, which is beneficial to their physiological functions. There are also many negative plants with white flowers, some of which are open at night, reflecting all the light waves, which is another adaptation measure. There are few black flowers in nature, and only a few flowers occasionally have black spots, because black absorbs all light waves and has too much heat, which is easy to be hurt.

from the evolutionary point of view, it has a development process. The flowers of gymnosperms are primitive, all with green color, while the anthers and pollen are yellow. In the spectrum, adjacent to green, one end of the long wave is yellow, orange and red, and the other end of the short wave is cyan, blue and purple. We can say that the color starts from green, develops to the long wave end, turns from yellow to orange, and finally appears red; Towards the short wave end, it is blue and purple. Red should be the latest color to appear, and it is the most vivid and dazzling in the evolutionary journey.

According to Darwin's theory of natural selection, insects play an important role. Hundreds of millions of years ago, when gymnosperms appeared on earth, there were not many insects. Anthocyanins are light, pollinated and fertilized, and all of them are wind-borne flowers. Later, angiosperms appeared and insects flourished. The flowers of angiosperms are divided into calyx and corolla with perianth (perianth and corolla are collectively called petals). Petals are no longer green, but more conspicuous yellow, white or other colors. The shape is also big, some have nectaries, secrete nectar, and some give off fragrance, which becomes insect-borne flowers. "Bees compete for the fragrance of the butterfly", and insects pollinate and fertilize the flowers.

finally, it is due to manual selection. The process of natural selection is slow, and it takes a long time to show its function. Artificial selection has greatly accelerated its process and achieved remarkable results in a short time. Peony, for example, took hundreds of millions of years by natural selection to create a wild original species. The flowers are single-petaled, and there is only one pink color. After artificial cultivation, just at that time in the middle of the Northern Song Dynasty (11th century), it took several decades for a single petal to create different postures such as multi-leaf, chiba (double petal), Lou Zi (flower heart protruding) and bing Di. Pink creates various beautiful colors such as crimson, flesh red, purple, dark purple, yellow and white. Another example is Dahlia, which is native to Mexico and has only eight red petals. The history of artificial cultivation is only two or three hundred years, but there are thousands of varieties with different shapes and colors. Another example is corn poppy, which has been cultivated in red, yellow, orange and white, but blue has never appeared. At the end of the last century, Pubank, a famous American horticulture breeder, discovered a corn poppy with a layer of fog on its petals and cultivated it specially. By the beginning of this century, it has bred various blue corn poppy with different shades, adding new varieties to flower gardening.

flowers are so red, which is a masterpiece of nature, but also the result of artificial cultivation.