使用化学药剂防除农田杂草是现代化农业生产中的一项重大技术措施。为什么除草剂只消灭杂草而不杀死作物呢?这是由除草剂的特性和作物与杂草的形态结构及生理特点的不同,加上环境条件所决定的。应当说明,所有的除草剂对任何植物都是有毒的,用量过大不论哪种植物都会致死,用量不足哪种植物都可以抵抗和忍耐,因此用量多少是个重要问题。施用一定剂量的某种除草剂,有些植物会受害死亡,另一些则不受其害。这叫做除草剂的选择性。在农作物中,植物的形态结构与除草剂的选择性密切相关。单子叶植物如小麦、水稻、玉 The use of chemicals to control farmland weeds is a major technological measure in modern agricultural production. Why does the herbicide eliminate only weeds without killing the crops? This is due to the characteristics of the herbicides and the differences in the morphological and physiological characteristics of the crops and weeds, plus the environmental conditions. It should be noted that all herbicides are toxic to any plant. In large quantities, plants of any kind are lethal and can be tolerated and tolerated to a lesser extent. Therefore, dosage is an important issue. Some herbicide is applied at a dose, some plants are killed and others are not affected. This is called herbicide selectivity. In crops, the morphological structure of plants is closely related to the selectivity of herbicides. Monocots such as wheat, rice, jade