水培条件下秋华柳对重金属Cd的富集特性及光合响应

采用水培试验的方法,研究了不同Cd胁迫浓度ρ(Cd2+)分别为0、1.5、10和20 mg/L]下秋华柳的生长、光合耐性及其对Cd的富集特性和转移能力.结果表明:①随着Cd胁迫浓度的升高,秋华柳生长所受到的抑制程度有所增加.除20 mg/L处理组外,其余各处理组的耐性指数(TI)均大于70,表现出较高的耐性.②低Cd胁迫浓度(1 mg/L)下秋华柳具有较好的光合耐性,当Cd胁迫浓度达到20mg/L时,秋华柳的光合系统才受到明显影响.③秋华柳对外源Cd的富集能力较强,随着Cd胁迫浓度的升高,秋华柳所积累的Cd显著增加且主要积累于根部,表现为叶<茎<根.当Cd胁迫浓度小于5 mg/L时,秋华柳根部吸收的Cd向地上部分转移的效果较好.试验显示,秋华柳对于较低Cd胁迫浓度(≤10 mg/L)具有较好的耐受性和富集能力,可用于三峡库区消落带表层土壤Cd污染严重区域进行植物修复.

Bioaccumulation and Photosynthesis Response of Salix variegate to Cadmium under Hydroponic Culture

A hydroponic experiment with different mass concentrations of cadmium(ρ(Cd),0,1,5,10,20 mg/L) was conducted to investigate the growth rate,photosynthesis response and enrichment properties of Salix variegate seedlings.The results showed that the growth rate of S.variegate decreased gradually with the increase of Cd concentration.Exceptingthe treatment of 20 mg/L,the tolerance indexes of S.variegate in all the other treatments were above 70,which indicatedahigh tolerance of S.variegate to Cd.Under low stress of Cd(1 mg/L),S.variegate showed high photosynthetic resistance;when the concentration of Cd reached 20 mg/L,its photosynthetic system was destroyed significantly.The Cd contents in the roots and shoots of S.variegate increased with increasing concentrations of exogenous Cd.The Cd contents in S.variegate decreased in the order of roots>stems>leaves.When the stress was below 5 mg CdL,the efficiency of Cd transportfrom the roots to shoots was higher than that under higher stress.Based on its high growth adaptation,tolerance and bioaccumulation to Cd(≤10 mg/L),S.variegate has considerable potential for application in Cd contaminated areas of the Three Gorges Reservoir region.