农业生产上的敌人一到秋天,许多树木的叶子渐渐变黄;风一吹,就飘落下来。不仅是叶子,高等植物的其他计多器官如花、果实和种子等,在一定时候也会发生脱落现象。为什么高等植物的这些器官到了一定时期就会自然脱落?原来,植物的器官脱落,往往是植物对不良环境条件的一种适应。树木的落叶就是迎接寒冬所作的准备。在热带地区,那里没有冬天,可是有些树木在干旱季节也会落叶,那是为了减少水分的蒸发, As soon as the enemy in agricultural production arrives in the fall, the leaves of many trees turn yellow; when the wind blows, it falls. Not only the leaves, but also other organs of higher plants such as flowers, fruits and seeds, will also fall off at certain times. Why do these organs of higher plants naturally fall off after a certain period of time? It is originally believed that the loss of plant organs is often an adaptation of plants to adverse environmental conditions. The fallen leaves of trees are the preparations for the winter. In the tropics, where there is no winter, but some trees will fall in the dry season, it is to reduce the evaporation of water,