When you watch TV programs about wild animals, it is surprising to see how an antelope can escape a lion’s attack. In the wilderness, everyone has a stunt. Even plants have their own ways of fighting off enemies. Over millions of years of evolution, plants have developed a unique defence system. Chemicals are wildly used for survival. By making their leaves, flowers, roots and fruits distasteful or poisonous(有毒的) to enemies, plants can fight back. One such plant is the Golden Wattle tree. The British scientist David Cameron has found when an animal eats the tree’s leaves, the amount of poison increases in the other leaves. “It’s like the damaged leaves telephoning the others telling them to fight together against the enemy, ” he said. The tree also sends defence messages to neighboring plants by giving out a special smell. Golden Wattle trees in the surrounding 45 meters will get the message and produce more poison within 10 minutes. Now, if an enemy eats too many of the trees’ leaves, it will die. Every species of plant or tree is good at the production of a particular set of chemicals. A herbivore that can safely eat the leaves of one tree may be poisoned by its neighbor. In this way, plants have developed not only individual defence system, but also shared it with others. This makes it impossible for a single animal to destroy even a small area of forest. 小题1: Which of the following can be the best title of the passage?
|