不同海拔微孔草抗氧化系统的比较研究

对生长在3个不同海拔自然生境下微孔草(Microula sikkimensis)叶中的抗氧化系统进行了比较研究.结果表明,生长在高海拔的微孔草叶中抗氧化酶类SOD、POD和CAT活性比生长在低海拔的活性高,其中大通牛场的微孔草叶中3种酶活性最高;APX的活性随海拔的升高而升高,且低海拔地区西宁的APX活性极显著低于高海拔地区大通和海北站(P<0.01);作为非酶抗氧化系统物质之一的抗坏血酸(ASA)含量随海拔的升高而降低.高海拔地区微孔草叶中可溶性糖含量极高(P<0.01);可溶性蛋白含量随海拔升高呈V字形变化.光合色素Chla、Chl b和Car的含量均随着海拔升高而增加,Chl a/b比值随海拔升高而降低.MDA的含量随海拔升高有增加的趋势,西宁和大通的相比较,MDA含量差异显著(P<0.05),说明微孔草叶细胞膜脂过氧化程度随海拔升高加剧.生长在不同海拔高度的微孔草对不同海拔高度环境变化具有相应的生理适应性和抗氧化策略.

Comparison of Antioxidative System in Microula sikkimensis at Different Altitudes

The comparative research of antioxidative system in the leaves of Microula sikkimensis growing at the different altitude outdoors was carrieded out.Our results revealed that the enzymes activity of superoxide dismutase(SOD),peroxidase(POD) and catalase(CAT) at high altitude regions were higher than that of Xining region,and the activities of SOD,POD and CAT at Datong was the highest among the there regions.With the increase of altitude,the activity of ascorbate peroxidase(APX) also increased,and the activities of APX at Xining was significantly lower than that at Haibeizhan and Datong(P<0.01);As one of the most important antioxidative matters,ascorbic acid(AsA) decreased from Xining region to Haibeizhan region.Contrarily,the content of Chl a,Chl b and Car increased along the elevational gradient from 2 200 m to 3 200 m.Soluble sugar content was increased remarkably at higer altitude region(P<0.01).Malondialdehyde(MDA) increased along the elevational gradient and the content of MDA at Datong region was obviously higher than that at Xining region(P<0.05),which resulted in the membrane lipid peroxidation in the cell of Microula sikkimensis leaves.The figure of the soluble protein content in the cell of Microula sikkimensis leaves at Xining region,Datong region and Haibeizhan region showed a "V" shape in there regions.The results of our research indicated that the plant Microula sikkimensis grown at the three regions in Qinghai Plateau could accordingly apply the environment changes in different altitude and had some physiological adaptability and antioxidative and defensive strategy.