蚯蚓-菌根在植物修复镉污染土壤中的作用

以灰化土(Aquods)为供试土壤,分别加入4个浓度的Cd2 (0,5,10,20mg/kg)模拟土壤污染,设置每钵接种8条蚯蚓(Pheretimasp.)、接种菌根(InoculumEndorize-Mix2)和同时接种蚯蚓和菌根的处理,以不加蚯蚓和菌根为对照,并种植黑麦草(Loliummultiflorum),研究蚯蚓菌根相互作用对Cd污染土壤中黑麦草生长及土壤中Cd生物有效性的影响。结果表明菌根浸染率不受添加Cd浓度的影响,平均浸染率为22%,加入蚯蚓能使菌根的侵染率提高9%。在Cd污染土壤上,引进蚯蚓显著增加了黑麦草地上部的生物量,接种菌根对黑麦草地上部分产量没有明显影响,同时接种蚯蚓和菌根与只接种蚯蚓相比没有显著差异。蚯蚓活动显著提高了土壤中CaCl2-Cd的含量,而菌根只在低浓度Cd处理上增加了土壤中CaCl2-Cd含量,二者对H2O-Cd、DTPA-Cd均无显著影响,蚯蚓和菌根对增加土壤有效态Cd含量不存在协同作用。蚯蚓活动促进了黑麦草对Cd的吸收,但吸收的Cd积累于黑麦草根部。接种菌根不仅能促进黑麦草对Cd的吸收,而且还能促进Cd从植物的根部向地上部分转移,由于接种蚯蚓可以提高菌根的浸染率,所以二者具有促进Cd向地上部转移的协同作用。这对于重金属污染土壤的植物修复具有十分重要的意义。

Roles of earthworm-mycorrhiza interactions on phytoremediation of Cd conta-minated soil

There has been increasing interest in developing a plant-based technology (phytoremediation) to remediate heavy metal-contaminated soils. The primary objective of this technology is to maximize the transfer of heavy metals to plants so that the greatest total mass of contaminant is removed by each cropping. Slow growth rate and low biomass of hyperaccumulating plants may limit the utility of phytoremediation technology. In addition, the low bioavailability of heavy metals in the soil also restrains this tec...