采用营养液培养法研究了200μmol·L^-1Cd 胁迫20 d 后17 个菊花[Dendranthema morifolium (Ramat.)Tzvel.]品种幼苗的外观形态及7 个生长指标(包括株高、根长、茎叶鲜质量、根鲜质量、茎叶干质量、根干质量和叶片相对电导率)的变化,并据此比较各指标胁迫指数的差异;基于8 个耐镉指标(包括单株叶片受害率以及7 个生长指标的胁迫指数),采用主成分分析、隶属函数值分析、综合得分分析和WPGMA 聚类分析方法对这些品种的耐镉性进行综合评价。结果显示:Cd 胁迫条件下各品种幼苗均表现出生长缓慢、植株矮小、叶片萎蔫黄化、根系生长不良等受害症状。不同品种的受害程度差异较大;各品种单株叶片受害率为3. 00% ~ 85. 05%,其中品种‘钟山黄英’单株叶片受害率最低;各品种株高、根长、茎叶鲜质量、根鲜质量、茎叶干质量、根干质量和叶片相对电导率的胁迫指数分别为65. 72% ~92. 86%、27. 45% ~ 87. 84%、29. 25% ~ 76. 54%、38. 10% ~ 77. 93%、51. 42% ~ 88. 23%、40. 48% ~79. 95%和140. 98% ~268. 79%,其中,品种‘钟山金葵’和‘钟山黄英’的受害程度均较轻。主成分分析结果表明:第1 主成分贡献率为81. 089%,其中8 个耐镉指标的载荷均较高,说明这些指标可基本反映菊花的耐镉性。各品种8 个耐镉指标的综合得分和隶属函数值差异较大,其中品种‘钟山金葵’和‘钟山黄英’的隶属函数值和综合得分均较高,其耐镉性分别排在第1 和第2 位。WPGMA 聚类分析将17 个菊花品种分为4 组,其中,品种‘钟山金葵’单独聚为Ⅰ组,品种‘钟山金山’、‘钟山红枫’、‘钟山樱桂’、‘钟山紫莲’和‘钟山丹桂’聚为Ⅱ组,品种‘钟山黄英’、‘钟山紫桂’和‘钟山金玉’聚为Ⅲ组,其余8 个品种聚为Ⅳ组,分别属于高耐镉型、镉敏感型、耐镉型和低耐镉型。通过综合分析,认为品种‘钟山金葵’、‘钟山黄英’、‘钟山紫桂’和‘钟山金玉’的耐镉性较强,可用于Cd污染土壤的植物修复。

Changes of morphology and seven growth indexes including plant height, root length, fresh weight of stem and leaf, fresh weight of root, dry weight of stem and leaf, dry weight of root and relative electric conductivity of leaf of seedlings of 17 cultivars of Dendranthema morifolium (Ramat.) Tzvel. After 200 μmol·L^-1 Cd stressed for 20 d were researched by nutrient solution culture method, and differences in stress indexes of each index were compared accordingly. Based on eight Cd resistance indexes including individual leaf damage rate and stress indexes of seven growth indexes, Cd resistance of these cultivars were comprehensively evaluated by methods of principal component analysis, subordinate function value analysis, comprehensive score analysis and WPGMA cluster analysis. The results show that under Cd stress condition, seedlings of each cultivar all appear suffer symptoms such as growing slowly, drawl plant, yellow and wilting leaf, poor growth root, etc. Differences in damage degree of different cultivars are great. Individual leaf damage rate of different cultivars is 3. 00% -85. 05%, in which, that of cultivar ‘Zhongshanhuangying’is the lowest. Stress indexes of plant height, root length, fresh weight of stem and leaf, fresh weight of root, dry weight of stem and leaf, dry weight of root and relative electric conductivity of leaf of different cultivars are 65. 72% -92. 86%, 27. 45% -87. 84%, 29. 25% -76. 54%, 38. 10% -77. 93%, 51. 42% -88. 23%, 40. 48% -79. 95% and 140. 98% -268. 79%, respectively, in which, damage degrees of cultivar ‘Zhongshanjinkui’ and ‘Zhongshanhuangying’ both are mild. The result of principal component analysis shows that contribution rate of the first principal component is 81. 089%, in which, load of eight Cd resistance indexes is higher, indicating that these indexes can basically reflect the Cd resistance of D. morifolium. Differences in comprehensive score and subordinate function value of eight Cd resistance indexes of each cultivar are great, in which, those of cultivar ‘Zhongshanjinkui’and ‘Zhongshanhuangying’are higher, their Cd resistance ranks the first and the second place, respectively. 17 cultivars of D. morifolium are divided into four groups by  WPGMA cluster analysis, in which, cultivar ‘Zhongshanjinkui’is clustered to Ⅰgroup alone, cultivar ‘ Zhongshanjinshan ‘, ‘ Zhongshanhongfeng ‘, ‘ Zhongshanyinggui ‘, ‘ Zhongshanzilian ‘and ‘Zhongshandangui’are clustered to Ⅱgroup, cultivar ‘Zhongshanhuangying’,‘Zhongshanzigui’and ‘Zhongshanjinyu’are clustered to Ⅲgroup, other eight cultivars are clustered to Ⅳgroup, which belong to high Cd resistance type, Cd sensitive type, Cd resistance type and low Cd resistance type, respectively. By comprehensive analysis, it is suggested that Cd resistance of cultivar ‘Zhongshanjinkui’, ‘Zhongshanhuangying’, ‘Zhongshanzigui’and ‘Zhongshanjinyu’is stronger, these cultivars can be used for phytoremediation of polluted soil with Cd.