巨菌草对镉污染土壤的修复特性

The remediation characteristics of Pennisetum spp.on Cd contaminated soil

通过盆栽试验研究四川盆地3种典型土壤类型(冲积土、紫色土和黄壤)下不同浓度镉(Cd)胁迫(CK:0 mg/kg;T1:20 mg/kg;T2:50 mg/kg;T3:100 mg/kg)对巨菌草的生长特性以及土壤中Cd富集特征的影响.结果显示:较低浓度(T1)的Cd处理并未对巨菌草的生长造成显著的影响,而较高浓度(T2、T3)的Cd胁迫严重抑制了巨菌草的生长;巨菌草的株高、各器官生物量以及总生物量均表现出随着处理浓度的增加而降低的趋势;同一Cd处理浓度下,不同土壤类型中巨菌草株高、各部分生物量以及总生物量均表现为冲积土>紫色土>黄壤.3种土壤中巨菌草根、茎和叶的Cd含量随着土壤Cd浓度的增大而显著增加,且表现为根>叶>茎,同时地下部分>地上部分;同一Cd处理浓度下,巨菌草各器官Cd含量均表现为黄壤>紫色土>冲积土,且与其他两种土壤相比,黄壤中生长的巨菌草具有较大的富集系数和转移系数,表明巨菌草在黄壤中表现出较好的吸收富集作用.各处理浓度下,巨菌草对Cd均表现出一定的吸收和富集特征,尽管巨菌草富集系数和转移系数小于1,但其对Cd具有较强的耐性,且地上部分Cd累积量在T3处理下最高达到1.24 mg/株.本研究表明巨菌草在Cd污染土壤的植物修复方面具有一定的应用潜能.

To study the effect of Cd stress on growth characteristics and Cd accumulation of Pennisetum spp. in three typical soil types of Sichuan （alluvial soil, purple soil and yellow soil）, a pot experiment was conducted with four levels of Cd treatment （CK： 0 mg/kg; T1： 20 mg/kg; T2： 50 mg/kg; T3： 100 mg/kg）. The results showed that higher Cd concentration （T2, T3） influenced the growth of Pennisetum spp. significantly, but low Cd concentration （T1） had no significant effects. The height, organ biomass and total biomass decreased with the increase of Cd concentration and showed an order of alluvial soil purple soil yellow soil under the same Cd concentration. The Cd content of root, stem and leaf showed a significant increasing tendency with the increase of Cd concentration with an order of root leaf stem in the three soil types. In addition, the Cd content of above ground parts was less than that of root, with the Cd content in each organ of Pennisetum spp. higher in yellow soil than the other two soil types. The bioaccumulation coefficient and tolerance index of Pennisetum spp. cultivated in yellow soil was higher than in other soil types, suggesting that Pennisetum spp. had a better repairing effect in the Cd polluted yellow soil. Pennisetum spp. had certain absorption and bioaccumulation characteristics in Cd contaminated soil, even with enrichment coefficient and transfer coefficient less than 1; it showed strong tolerance to Cd with Cd accumulation up to 1.24 mg/plant under T3 treatment. The results indicated that Pennisetum spp. has certain potential application value in phytoremediation of Cd contaminated soil.