比拉底白刺苗期抗旱性分析

Drought resistance analysis of Nitraria billardieri seedlings

为研究澳大利亚荒漠植物比拉底白刺的抗旱性,以比拉底白刺幼苗作为研究材料,在100 mmol/L甘露醇溶液模拟干旱的环境下,观察了植物形态变化,测定了植物的相对含水量(relative water content,RWC)、过氧化物酶活性(peroxidase,POD)、丙二醛(malondiadehyde,MDA)以及游离脯氨酸(proline,Pro)含量的动态变化。结果表明,干旱处理过程中,比拉底白刺叶片从基部往上逐渐萎蔫变黄,推测其通过保护顶芽的生命力以适应干旱环境;相对含水量前期相对稳定,后逐渐下降;POD活性先缓慢升高,后快速上升;游离Pro浓度总体呈上升趋势;MDA含量先升后降。差异显著性分析表明,与对照相比,POD和游离Pro的变化趋势与对照组相比差异显著,说明二者与比拉底白刺的抗旱性具有相关性,通过减少质膜过氧化保护细胞完整性;MDA含量变化不明显,可能由于POD和游离脯氨酸的作用使得白刺细胞的膜脂系统未遭受活性氧自由基的强烈攻击。

The drought resistance research of Australia desert plantsNitraria billardieriwas focused by observing mor-phological changes and analyzing variation trends of relative water content（ RWC）, enzymatic activity of peroxidase（POD）, malondiadehyde（MDA）, and proline（Pro） under drought stress simulated by 100 mmol/ L mannitol solution.The results showed that the leaves turned yellow under drought stress and withered gradually from base to top, presuma-bly by protecting the vitality of buds to adapt the arid environments. The relative water content kept relatively stable atearly stage and then decreased gradually. The POD activity increased slowly at first and then increased rapidly. Free Proconcentration had been rising during the treatment. MDA content increased at first and then decreased. According to thestatistical analysis, both POD and free Pro increased obviously compared with control group. They reduced plasma mem-brane peroxidation and kept the cell integrity which showed drought resistance ofNitraria billardieri. MDA concentrationdid not change significantly, this indicated that cytoplasmic membrane system was protected and did not seriously sufferfrom reactive oxygen free radical attacking under drought stress probably caused by increased concentration of POD andfree Pro.