我国大部分地区属于北温带,每逢秋季,由于气温较低,雨水减少,使得植物的根部吸收作用降低,植物体得到的水分与无机盐大量减少,从而不能正常地进行光合作用、呼吸作用和蒸腾作用(指水分从活的植物体表面主要是从叶子上,以水蒸气状态散失到大气中的过程)等生理活动。如果继续保留叶子,植物体就会蒸腾出大量水分,从而威胁到自身的生命。但是,只要度过寒冷与干燥的季节之后,新的叶片就 Most areas of our country belong to the north temperate zone. Every autumn, due to the lower temperature and less rainfall, the absorption of plant roots is reduced, and the water and inorganic salts obtained by plants are greatly reduced, so photosynthesis, respiration and Transpiration (refers to the water from the living plant surface mainly from the leaves, the state of water vapor lost to the atmosphere) and other physiological activities. If you continue to retain the leaves, plants will evaporate a lot of water, thus threatening their own lives. However, as long as the cold and dry season, the new leaves on