中文摘要：

对西宁地区唐古特山莨菪（Anisodus．tanguticus．）抗氧化系统成分的季节变化及日变化的研究发现：抗氧化物质谷胱甘肽和类胡萝卜素的含量在生长的前3个阶段变化趋势一致，由低升高再降低；日变化显著差异；抗氧化酶的活性表现不一致，过氧化物酶、过氧化氢酶和抗坏血酸过氧化物酶的活性随生长进程表现出降低-升高-降低的变化趋势，均为枯黄期活性最低；日变化活跃，但是没有明显的规律性；超氧化物歧化酶活性在营养生长初期最高并且日变化幅度大，其他时期日变化不大；丙二醛含量在返青期上午较高而在午后迅速降至最低水平；营养生长初期和后期的含量低，日变化差异不大；枯黄期的含量总体表现出较高的水平。研究结果表明抗氧化物质和抗氧化酶在不同生长季节具有协同性和互补性，山莨菪在不同的生长期可能存在不同的抗氧化机制。

英文摘要：

To study the seasonal and diurnal variations of the antioxidative system ingredients in Anisodus tanguticus Pascher, the plant leaves were collected from the A. tanguticus Pascher cultivated garden near Xining city during the plant growing season. The results show that the contents of glutathione and carotene exhibited the same variation tendency in the nutrient periods ： first ascending then descending ; the difference of diurnal change was significant. The activities of antioxidative enzymes were varied during the plant growing season： the activity of peroxidase, catalase, and ascorbate peroxidase ebbed and flowed in a descend-ascend-descend tendency from the early vegetative growth period to the deficient state in the withering period. Significant changes occurred in the daytime, though with no regularity. The activity of superoxide dismutase was intense in the early vegetative growth period and, more particularly, the enzyme diurnal change was more notable than in the other three periods. The malondialdehyde content in the plant leaves was high during the plant turning-green period but rapidly descended to the lowest. The MDA content in the plant early and late vegetative growth periods fell to the lowest and showed no significant diurnal varieties; though during the plant withering period, the MDA content became higher than in any other periods. All these results show that Anisodus tanguticus Pascher boasts a different antioxidative mechanism in each different growing season; its capacity of antioxidation is determined by the whole antioxidative system; and the changes of contents or activities of a few substances cannot impair its antioxidative capacity.