庄稼地里施了除草剂,大量杂草会被杀死,而庄稼苗却安然无恙。为什么除草剂会杀草而保苗呢? 其一,不同植物对一种药剂的抗药力是不一样的。这是由于不同植物对药剂的分解能力不同。首先表现在有些作物体内有解毒物质,把除草剂分解为无毒物质。如玉米田喷施西马律或阿特拉津,棉田施用扑草净,杂草吸收药后,叶片不能进行光合作用,而玉米、棉花能将药剂分解为无毒物质,起到杀草保苗作用。其二,作物与杂草在形态及生态上有差异。如禾本科作物叶片狭小,有较厚的角质层和蜡质层, Herbicide was applied to the crops, a large number of weeds were killed, and crop seedlings were safe and sound. Why herbicides will kill grass and seedlings? First, different plants on a drug resistance is not the same. This is because different plants have different ability to decompose medicaments. First of all, it shows that in some crops, there are detoxifying substances that break down the herbicides into non-toxic substances. Such as cornfield spraying Xi Ma or atrazine, cotton field prometryne, weed absorption medicine, the leaves can not be photosynthetic, and corn, cotton can decompose the agent into non-toxic substances, play a grass seedling effect. Second, crops and weeds vary in morphology and ecology. Such as grass crop leaves narrow, thick cuticle and waxy layer,