Abstract: To investigate the shade tolerance of Carex L. plants in Gansu region,this experiment established four shading gradients (0%,30%,60%,90%) to assess the plant height,relative water content,and physiological indicators of their leaves. Principal component and membership function analysis were used to select wild Carex plants with good shade tolerance which were suitable for planting in the northwest region. The results showed that the plant height and relative water content of leaves continually increased with the enhancement of shading gradient. The activities of superoxide dismutase and catalase first increased and then decreased with the increase of shading gradient. The trend of changes in the content of soluble protein was opposite. The content of malondialdehyde first increased,then decreased,and then increased with the increase of shading gradient. The comprehensive evaluation showed that Carex moorcroftii (Tianzhu),Carex breviculmis (Linxia),and Carex melanostachya (Chongxin) had strong shade tolerance. The result could provide selection basis for landscaping plants in the northwest region.

Key words: Wild Carex, Shading gradient, Physiological indicators, Principal component analysis, Membership function analysis

摘要： 为研究甘肃地区苔草属(Carex L.)植物耐荫性强弱，本试验设置4个遮荫梯度(0%，30%，60%，90%)，对其叶片的株高、叶片相对含水量和生理指标进行观察测定，运用主成分和隶属函数分析筛选出适宜西北地区种植的耐荫性好的野生苔草属植物。结果表明：株高和叶片相对含水量随着遮荫梯度的增强持续升高；超氧化物歧化酶活性和过氧化氢酶活性随着遮荫梯度的增强先升高后降低；而可溶性蛋白含量的变化趋势与之相反；丙二醛含量随着遮荫梯度增强先升高再降低后升高。综合评价表明青藏苔草(天祝)、青绿苔草(临夏)和凹脉苔草(崇信)耐荫性较强，本研究可为西北地区园林绿化植物提供选择依据。

关键词: 野生苔草, 遮荫梯度, 生理指标, 主成分分析, 隶属函数分析