他感作用是指植物通过根、芽、叶、花等器官释放于环境中的生化物质对自身或其它植物直接或间接的相生或相克作用[1]。例如苹果的老根腐解能产生一种酚类物质，明显抑制苹果根系的发育;桃树的根中发现有扁桃忒，分解后产生苯甲醛，严重毒害桃树的更新［2.3］。而关于这些生化物 He sense of role refers to the plant through the roots, buds, leaves, flowers and other organs released into the environment of biological or other plants themselves and other plants directly or indirectly, the role of phase or phase g [1]. For example, the old root rot of apple can produce a kind of phenolic substance, which obviously inhibits the development of apple root system. Almonds are found in the roots of peach tree, and benzaldehyde is decomposed after it is decomposed. And about these biochemicals