一.引言植物在生活过程中需要許多矿质元素的足量供应,才能保証正常地生长发育,或发揮其最大生产潜力。如果某种必需的矿质元素缺少或供应不足,就会影响到植物体内生理生化过程的正常进行,随着时間延长,也会引起外部形态上的变化,特别是生长显著下降,严重者致死。在人为控制条件下的砂基培养試驗, I. INTRODUCTION Plants need sufficient supply of many mineral elements in their daily life to ensure their normal growth and development or their maximum productive potential. If a necessary mineral element is lacking or under-supplied, it will affect the normal process of physiological and biochemical processes in plants. With the extension of time, it will also cause external morphological changes, especially the significant decrease of growth and death in severe cases. Under artificial control conditions of sand-based culture test,