酸胁迫下紫花苜蓿的生理耐受极限

Physiological Tolerance Limit of Medicago Sativa under Acid Stress

用沙培结合营养液培养的方法,以紫花苜蓿WL525为实验材料,通过模拟典型南方酸性土壤中的酸胁迫因子,对苜蓿幼苗进行不同酸度环境下的酸胁迫实验,探讨紫花苜蓿对于各酸度的生理耐受极限。研究结果表明:pH为4的环境酸度是苜蓿幼苗能够耐受的生理极限。在此酸度环境下,植株的根系活力,光能转化效率,尚能维持在与对照差异不大的水平上,可以维持正常生长。在撤除胁迫后生理指标恢复到较好的生长状态。当环境pH值低于该水平时,植株不能耐受。随环境pH值的降低,叶绿素浓度、光合转化效率和根系活力显著下降。

Alfalfa （Medicago sativa. L） is a kind of perennial forage grass of leguminous, growing rapidly and widely cultivated in the world. But if we want to promote its acidic and iron-rich soil occupying 40% of the whole world ,we will face the stress factor that reduce yield of alfalfa in acid soil. In the experiment, we study the acid stress simu- lates solely forces of factor, discuss alfalfa regarding limit for acidity tolerance, we found that Alfalfa has the difference for the different acid treatment germination response, pH = 4 is the lowest acidity of Alfalfa, in the environ- ment, the Alfalfa shows the symptom caused by acid, but the difference vigorous roots, photosynthesis efficiency cornparison are not obvious, and may maintain the normal growth. After the removal forces of acid, the symptom in acid will be possible to vanish gradually, restores to the better growth condition. When the pH value is lower than this level,the plant couldnt tolerant.