Because after the end of the ice age, the climate in the northern hemisphere has become increasingly warmer, which is more suitable for the growth of European spruce, laying a good foundation for its

Because after the end of the ice age, the climate in the northern hemisphere has become increasingly warmer, which is more suitable for the growth of European spruce, laying a good foundation for its great development. However, Siberian spruce, which is suitable for growing in cold environments, lacks the ability to compete due to changes in climate conditions, and has to lose ground. Based on the outcome of this battle for plant territory, Sorokina also predicted that if the climate warms further, European spruce will also compete for the territory of Asian spruce, expanding the battlefield to Asia. Sorokina used climate factors to explain the war between European spruce and Siberian spruce, but she could not explain many phenomena that occurred in the United States, that is, the war between exotic plants and native plants.

Since the beginning of the 20th century, the United States has introduced a large number of exotic plants from all over the world in order to beautify the environment. As a result, unexpected disasters have occurred. For example, kudzu, a leguminous plant introduced from Asia, has become the fastest growing and most difficult to suppress plant in the hot and humid southern United States. Kudzu suddenly invaded a large area of ??land in the southern United States. Especially after entering the forest, it used its soft body that was good at climbing to climb to the heights of the big trees, stretching out its large leaves and blocking a lot of light. Its roots also try their best to penetrate deep into the ground to absorb water, causing other plants to dry up and die.

There are many more examples in this regard, and they are attracting more and more attention from scientists. Professor Britt, a scholar at Florida State University in the United States, pointed out that without human intervention, these introduced alien plants will "annihilate" the native plants. Botanist Ewell even exclaimed that the large-scale expansion of this alien plant has seriously damaged the local ecological environment and will pose a fatal threat to the natural fauna here.

Currently, botanists have little way to deal with the dangers posed by exotic plants because they do not yet fully understand why they win in turf wars. If foreign plants drive other plants away by secreting chemicals, then why don’t they have this obvious advantage in their homeland? It would be even more illogical to say that the victory of alien plants is caused by natural factors of growing conditions, because theoretically, native plants are definitely more adapted to local growing conditions, while alien species thousands of miles away cannot adapt to The ability should be less than that of native plants.

In order to uncover the mystery of plant wars and save those who are defeated, scientists from various countries are exploring the physiological mechanisms of battles between plants in a deeper and more comprehensive manner.