中文摘要：

本试验以盆栽黑麦草幼苗为材料,研究了不同的胁迫时间（7,14,21,28d）,不同的铅浓度（500,1 000,1 500mg/L）对黑麦草的抗氧化酶（SOD、POD）、细胞膜（MDA、相对电导率）及渗透调节物质（SS、Pro）的影响。结果表明,随着铅浓度的增加,黑麦草叶片中的SOD活性变化整体为先上升后下降,在低浓度（500和1 000mg/L）和短时间（7和14d）胁迫下SOD活性明显升高,之后快速降低。POD活性随着胁迫时间及铅浓度增加呈显著的下降趋势,在28d时,1 500mg/L浓度下,POD活性最低,为45.9U/g。随着胁迫时间及铅浓度的增加,MDA含量及相对电导率整体呈上升趋势,且MDA含量与铅浓度呈线性正相关（r2〉0.96）。可溶性糖（SS）含量变化复杂,在较高浓度及较长时间作用下趋于减少。脯氨酸（Pro）含量在较低铅浓度胁迫下会明显增加,但浓度过高超过黑麦草忍耐极限,就会有所下降。表明黑麦草在重金属铅胁迫中经历了一个忍耐和逐渐受损的过程。

英文摘要：

The effects of lead concentrations（500,1 000,1 500 mg/L） on the antioxidant enzymes（SOD,POD）,cell membrane（MDA,the relative conductivity） and osmoregulation substances（soluble sugar and proline） in the leaves of perennial ryegrass（Lolium perenne） were studied after different stress durations（7,14,21,and 28 d） in a pot experiment.SOD activity increased initially and then decreased with the increase in lead concentration.At lower concentrations（500,1 000 mg/L） and shorter durations（7,14 d）,SOD activity significantly increased but then declined rapidly.POD activity decreased significantly with increases in stress duration and lead concentrations.POD activity was minimum（45.9 U/g） at the 28th day and 1 500 mg/L of lead.With increases in stress duration and lead concentrations,MDA content and the relative conductivity generally increased.MDA content was positively linearly correlated with lead concentration（R20.96）.Soluble sugar content showed complex change trends,and tended to reduce at the higher concentrations and longer durations.Proline content significantly increased at the lower lead concentrations.If lead concentration exceeded the limit of perennial ryegrass tolerance,proline content would decline.It indicated that perennial ryegrass can be tolerant to lead stress but there is progressive damage under the stress.