蚯蚓在植物修复铜、镉污染土壤中的作用

Roles of Earthworm in Phytoremediation of Copper and Cadmium Contaminated Soil

以红壤和高砂土为供试土壤，分别加入3个浓度的重金属铜离子Cu^2＋（100，200，400mg·kg^-1）或镉离子Cd^2＋（5，10，20mg·kg^-1），每钵接种6条蚯蚓（Pheretima sp．），种植黑麦草（Lolium muhiflorum），以不加蚯蚓为对照（CK），研究蚯蚓活动对Cu、Cd污染土壤中黑麦草生长及铜、镉生物有效性的影响．结果表明，添加蚯蚓显著提高了Cu^2＋、Cd^2＋污染的高砂土中黑麦草地上部分的生物量，增幅为33％～96％；仅增加了Cu^2＋污染浓度低于200mg·kg^-1的红壤中黑麦草地上部分的生物量；添加蚯蚓显著增加了两种土壤中速效N的含量，促进了黑麦草地上部分对N的吸收，对速效P、K的含量以及黑麦草中P、K含量无显著影响；添加蚯蚓显著提高了红壤中铜（Cu）、镉（Cd）DTPA提取态的含量，对高砂土中DTPA提取态Cu、Cd的含量无显著影响；增加了高砂土中和添加Cu污染浓度低于200mg·kg^-1的红壤中黑麦草地上部分吸收Cu的总量，而对黑麦草吸收Cd的量无显著影响．加入蚯蚓可以不同程度地改善植物修复技术应用中受制的两个主要因素．

The objective of this study was to investigate the effects of earthworm on ryegrass growth in copper（Cu） and cadmium （ Cd ） contaminated soils, and on bio-availability of Cu or Cd in two soils, red soil from Jiangxi Province and orthic aquisols from Jiangsu Province. Each soil was amended and contained Cu^2＋ 0, 100, 200 and 400 mg·kg^-1 and Cd^2＋ 5, 10 and 20 mg·kg^-1 by adding appropriate concentrations of CuSO4 and CdCl2 , respectively. After the metal-treated soil was incubated for two months, six earthworms （Pheretima sp. ） were introduced into half pots, while the other pots contained no earthworms. Each pot received 15 pre-germinated ryegrass seeds （Lolium multiflorum）. The study indicated that ryegrass biomass was increased significantly from 33% to 96% by earthworm activity in orthic aquisols added with either Cu or Cd compared with the control without earthworms. And in red soil under 200 mg·kg^-1 Cu^2＋ addition, earthworm activity also increased ryegrass biomass, but slightly affected red soil with Cd addition. Earthworm activity markedly enhanced the concentration of available N in red soil and orthic aguisols, and increased N uptake by ryegrass, but had little effect on available P and K contents in the two soils and P and K in ryegrass. The concentration of DTPA-extracted Cu or Cd was increased significantly by earthworm activity in red soil, but slightly in orthic aquisols. The total uptake of Cu by ryegrass was significantly increased in orthic aguisols and red soil with the treatments of 0 or 100 mg·kg^-1 Cu^2＋ addition. No significant difference was observed in total uptake of Cd between the treatments with and without earthworms. Tab 4, Ref 30