What will happen to plants and animals before it rains?

Plants that can forecast the weather \ x0d \ x0d "People don't know spring birds know spring, and birds don't know spring grass." It has been found that not only many animals have the ability to observe the earth, but also some plants have this "magical ability". In the plant kingdom, some members can forecast the weather like meteorological stations. \x0d\\x0d\ There is a wonderful flower growing in Xishuangbanna, China. When the storm comes, a large number of flowers will bloom. According to this feature, people can know the weather changes in advance, so it is called "Rain Flower". Rain flower, also known as red rain curtain, calamus lotus and leek, is an herb flower of Allium in Amaryllidaceae. Its leaves are flat and linear, much like the long leaves of leeks, hanging in an arc. Bulbs are round and slightly thicker than onions. Flowers bloom in spring and summer, and the flowers are pink or rose red. China is native to Mexico and Cuba. It likes to grow on fertile, well-drained and slightly sticky soil and is not cold-tolerant. \x0d\\x0d\ So, why can rain be predicted? It turns out that before the storm, the external atmospheric pressure decreased, the weather was sultry, and the transpiration of plants increased, which made the bulbs of yuhua trees store nutrients produce a large number of hormones to promote flowering, prompting them to bloom a large number of flowers. \x0d\\x0d\ is unique. In Australia and New Zealand, there is also a strange flower, which can also predict whether the weather is sunny or rainy, so people call it "Rain Flower". This kind of flower is very similar to the chrysanthemum in our country, with long petals and various colors and patterns. The difference between the two is that the flowers of Yuhua are 2-3 times larger than chrysanthemums. \x0d\\x0d\ Scientists found through research that the secret of rainfall forecast is that its petals are very sensitive to humidity. When the air humidity increases to a certain extent, their petals will shrink and tightly wrap the stamens; And when the air humidity decreases, its petals will slowly spread out. Before going out, local residents always read the newspaper Yuhua. If the flowers bloom, it won't rain. If the flowers shrink, it means that it will rain. Therefore, people affectionately call it a "plant meteorologist". \ x0d \ x0d \ Flowers know the weather, and vegetation reports the weather. Perennial herbs Zoysia japonica and thatch can also predict the weather. When Zoysia Zoysia appears moldy hairs at the junction of leaves and stems, or when the junction of leaves and stems of thatch bubbles, it means rainy days. Therefore, there is a saying that "Zoysia japonica grows mildew and it will rain"; The proverb "The straw stalks spit, and it will rain tomorrow". \ x0d \ x0d \ Interestingly, grass can not only forecast the weather, but also measure the temperature. There is a "temperature grass" in southern Sweden, which can measure the temperature like a thermometer. This kind of grass has rectangular leaves and blue, yellow and white flowers, so it is also called "pansy" (figure 19). Its leaves are extremely sensitive to temperature. When the temperature is above 20℃, the leaves extend obliquely upward. If the temperature drops to 15℃, the blade will move down slowly until it is parallel to the ground. When the temperature drops to 10℃, the blades extend obliquely downward. If the temperature rises, the blades will return to their original state. Local residents can know the temperature according to the extension direction of its leaves. \ x0d \ x0d \ More interestingly, trees can also forecast the weather. In Dinglong Village, Xincheng County, Guangxi, China, there is a green bar tree that is over 100 years old. Its leaf color changes with the weather: on sunny days, the leaves are dark green; After a long drought, the leaves turn red; When the weather cleared up after the rain, the leaves returned to their original dark green. Local residents can know whether it is cloudy or sunny according to the color change of leaves, so people call it a "meteorological tree" (Figure 20). \x0d\\x0d\ Scientists have solved the mystery that the color change of Cyclobalanopsis glauca leaves can predict the weather through research. It turns out that in addition to chlorophyll, leaves also contain lutein, anthocyanin, carotene and so on. Chlorophyll is the main pigment in leaves. In the process of tree growth, when chlorophyll metabolism is normal, it has an advantage in leaves, and other pigments are covered, so leaves are green. Because this kind of Qinggang Tree is very sensitive to climate change, it is often sultry and sunny for a while before the long-term drought is about to rain. At this time, the synthesis of chlorophyll in leaves was inhibited, while the synthesis of anthocyanin accelerated and was first synthesized in leaves, so leaves turned from green to red. When rain, drought and strong light were removed, the synthesis of anthocyanin was inhibited again, but the synthesis of chlorophyll was accelerated, which made the color of leaves return to the original dark green. \x0d\\x0d\ A strange tree (called "Pu Shu" by locals) near Dateng Village, Hexian County, Anhui Province, with a height of 7m, a tree circumference of more than 3m, and a crown coverage area of 100 m2, is also a veritable "meteorological tree". According to the early and late germination and the density of leaves, we can know the rainfall of that year. For example, Grain Rain germinated before, and the buds were leafy, indicating that there was much rain and frequent floods in that year; If the germination is normal and the leaves are sparsely distributed, it means that the weather is good; If germination is delayed and leaves grow less, it is a year with little rain, and severe drought often occurs.