中文摘要：

利用2个耐盐和2个盐敏感的陆地棉品种，分别设置对照和4% （40 g L–1）浓度NaCl溶液处理三叶期幼苗，处理72 h后调查盐害指数，测定地上部分鲜重、根鲜重、叶片相对含水量、叶绿素荧光参数、相对电导率、丙二醛含量、抗氧化酶类活性等13个与耐盐性相关的重要指标。利用灰色关联聚类、主成分分析和逐步回归等方法综合评价陆地棉苗期耐盐性，认为最大光化学效率（Fv/Fm）可以作为鉴定陆地棉苗期耐盐性的关键指标，构建耐盐指数（y）方程y = 1.943x – 0.882，（x = 最大光化学效率），同时结合另外2个耐盐和2个盐敏感品种所得方程y值对耐盐等级进行划分。进一步利用23个已知耐盐性的品种检验方程，计算结果与田间鉴定结果完全一致。因此选用最大光化学效率作为唯一指标鉴定陆地棉苗期耐盐性，高效准确，同时通过构建方程和划分耐盐等级，为未来大规模陆地棉品种资源耐盐性鉴定提供技术标准和研究基础。

英文摘要：

Three-leaf cotton seedlings of two salt-tolerant varieties and two salt-sensitive varieties were treated by water and 4% （40 g L–1） NaCl solution, respectively. A total of 13 parameters related to salt tolerance including salt injury index （SII）, shoot fresh weight （SRW）, root fresh weight （RFW）, leaf relative water content （RWC）, chlorophyll fluorescence parameters （Fo, Fm, Fv/Fm）, relative conductivity （RC）, manlondialdehyde （MDA） content and the activity of antioxidant enzymes were monitored after 72h of treatment. Comprehensive assessment of salinity tolerance based on grey relation clustering method, principal component analysis and stepwise regression analysis indicated that themaximum quantum yield of PSII was the most significant correlated indices with salt tolerance in upland cotton, which could be used as a single parameter to assess salt tolerance based on the equation： y = 1.943x – 0.882 （where y is the salt tolerance index, x is the related value of maximum efficiency of photosystem II）. The other two salt-tolerant varieties and two salt-sensitive varieties were used to rate the classification of salt tolerance. Salt tolerance index （y） of 23 varieties with known salt tolerance were calculated to validate the accuracy of the equation, the result was consistent with field investigation. In this study, the maximum efficiency of photosystem II was used as the main index to validate the salt tolerance in cotton, together with the construction of salt tolerance index equation and salt tolerance rating, which could greatly improve the efficiency of salinity tolerance evaluation for massive germplasm in future.