在华北地区我们经常会看到果园里有的桃树、苹果树或梨树等的树稍叶子黄了,尤其是在雨季较为严重。这是怎么回事呢?通过科学实验证明,这是由于片缺乏铁营养引起的生理病害,称为“黄叶病”。植物发生黄叶的原因很多,不都是因为缺铁。那么缺铁引起的“黄叶病”又怎样和其他黄叶现象区别开呢? 首先要了解铁在植物体内起什么作用,为什么缺乏铁营养后树梢(枝条的顶端)叶子首先会发黄?现在知道,植物主要是靠光合作用制造生长所需要的有机 In North China, we often see some orchards in the orchard, apple trees or pear trees and other trees slightly yellow leaves, especially in the rainy season is more serious. This is how the case? Through scientific experiments show that this is due to the lack of iron nutrition caused physiological disease, known as the “yellow leaf disease.” There are many reasons for yellow leaves in plants, not all because of iron deficiency. Then iron deficiency caused by the “yellow leaf” and how the yellow leaves and other phenomena and how to distinguish it? First of all to understand the role of iron in the plant body, why the lack of iron nutrition after the tree tops (branches of the top) leaves first yellow? Now know that plants are mainly organic by the photosynthesis needed for growth