Abstract: Heavy metal stress is one of main environmental stresses and greatly affects growth and development of plants and their productivity and ecological functions. In order to investigate the physiological differences and tolerance mechanisms of different turfgrass species to cadmium stress,and to apply them to landscape creation in a rational way,three turfgrass species,i.e.,Trifolium repens,Festuca arundinacea,and Lolium perenne,were used as the experimental materials in the present study. A cadmium concentration gradient was set,i.e.,0,200,500,1 000,and 2 000 mg·kg^-1. After being treated for 60 day,the physiological activities and the ultrastructures of leaf cells were investigated. The results showed that the photosynthetic pigments content of the three turfgrasses showed a decreasing trend with increasing Cd²⁺ concentration,the levels of activities of superoxide dismutase (SOD) and peroxidase (POD) and malondialdehyde (MDA) content totally increased,and the activities of catalase (CAT) showed irregular changes,as Cd²⁺ concentrations increased. The damages to the ultrastructures of the leaves in three turfgrasses species were caused by the high Cd²⁺concentrations. Meanwhile,the grana lamellae of chloroplasts were blurred or dissolved,and even induced cells plasmolysis. Our results suggest that F. arundinacea and L. perenne could be used in soils polluted by high Cd concentrations,and T. repens could be used in soils polluted by low Cd concentrations.

Key words: Cadmium stress, Trifolium repens, Festuca arundinacea, Lolium perenne, Physiological activities, Ultrastructure

摘要： 重金属胁迫是常见的环境胁迫之一, 对植物的生长发育及其生产力和生态功能具有重大影响。为探究不同草坪草种对镉胁迫的生理差异及耐性机制, 并将其合理应用至景观营造, 本研究以白三叶(Trifolium repens)、高羊茅(Festuca arundinacea)和黑麦草(Lolium perenne)为试验材料,采用盆栽试验法,将Cd²⁺处理浓度设置为:0,200,500,1 000,2 000 mg·kg^-1。经处理60 d后测定草坪草各项生理指标并观察叶片细胞超微结构。结果表明:随Cd²⁺浓度增加,3种草坪草的光合色素含量呈下降趋势,超氧化物歧化酶(Superoxide dismutase,SOD)、过氧化物酶(Peroxidase,POD)活性和丙二醛(Malondialdehyde,MDA)含量总体上为上升趋势,过氧化氢酶(Catalase,CAT)活性呈先升后降趋势;高浓度的镉胁迫对3种草坪草叶片超微结构造成损伤,其叶绿体内基粒片层结构模糊或溶解,部分细胞发生质壁分离。因此,建议在Cd污染较重的土壤选用高羊茅和黑麦草,Cd污染较轻的土壤选用白三叶。

关键词: 镉胁迫, 白三叶, 高羊茅, 黑麦草, 生理特性, 超微结构