锌是果树生长发育不可缺少的营养元素,缺锌时,树体内生长素含量降低,细胞吸水少,不能伸长,枝条下部叶片常有班纹或黄化部分。苹果树缺锌,枝条顶部叶片狭小,或枝条纤细,节间短,叶密集丛生,质厚而脆,即通常说的小叶病。严重缺锌时从新梢基部向上逐渐落叶,果实小,畸形。因为缺锌,使树体内过氧化氢酶的活性降低,过氧化 Zinc is an indispensable nutrient element for the growth and development of fruit trees. When zinc is deficient, the content of auxin in the tree is reduced, the cells are less hygroscopic and can not elongate. Zinc deficiency of apple trees, narrow leaves at the top of branches, or thin branches, internodes short, dense clusters of leaves, thick and brittle, that is, the lobular disease is usually said. Serious zinc deficiency from the tip of the shoots gradually deciduous upward, the fruit is small, deformity. Because of zinc deficiency, so that the activity of catalase in the tree decreased, peroxidation