大花萱草对镉的耐性及积累特性

Characteristics of cadmium tolerance and enrichment of Hemerocallis fulva

通过盆栽试验研究了大花萱草对镉(Cd)的耐性及积累特性。结果表明:Cd浓度为0.5mg·kg-1时刺激大花萱草的生长,大于5mg·kg-1时抑制大花萱草生长,Cd浓度小于5mg·kg-1时延长了大花萱草的绿期和花期;随着Cd浓度的增大,大花萱草根系活力、叶绿素含量和含水量逐渐降低,游离脯氨酸和可溶性糖含量先升高后降低,细胞膜透性逐渐升高;Cd在大花萱草体内分布为根系>地上部分,随着Cd浓度的增大,大花萱草根系和地上部分Cd含量逐渐升高、富集系数和转运系数逐渐降低;Cd浓度为20mg·kg-1时大花萱草对Cd的积累量最大,为1.489mg·株-1。综合分析大花萱草的生长、生理变化及富集Cd的能力,大花萱草适用于浓度小于1mg·kg-1的Cd污染土壤的修复。

A pot experiment was conducted to study the cadmium （Cd） tolerance and enrichment of Hemerocallis fulva at different levels of Cd addition. The growth of H. fulva was stimulated when growing at Cd level 0. 5 mg kg-1, but inhibited when the Cd level was higher than 5 mg kg-1. The greening and flowering periods of H. fulva were prolonged at Cd level less than 5 mg kg-1. With the increasing concentration of Cd in the medium, the root activity and leaf chlorophyll and water contents decreased, leaf free proline and soluble sugar contents decreased after an initial increase, and leaf membrane permeability increased gradually. The absorbed Cd in H. fulva was more distributed in root than in shoot. With the increasing concentration of medum Cd, the Cd concentration in shoot and root increased, but the enrichment coefficient and translocation coefficient decreased. The maximum accumulation of Cd in H. fulva was 1. 489 mg plant-1 when growing at Cd level 20 mg kg-1. Based on the growth characteristics and Cdenrichment capability, H. fulva could he a potential plant used for the remediation of Cd-polluted soil when the soil Cd concentration was less than 1 mg kg-1.