外加不同铁源和丛枝菌根对砷污染土壤上玉米生长及磷、砷吸收的影响

Effects of different iron sources and arbuscular mycorrhiza on the growth and phosphorus and arsenic uptake by maize plants (Zea mays L.) in As contaminated soil

通过盆栽模拟试验研究了添加不同铁源及接种丛枝菌根真菌(Arbuscular mycorrhizal fungi,AMF)对高砷污染土壤上玉米生长及其吸收磷、砷、铁、锰、铜和锌的影响.试验结果表明,与对照相比,添加硫酸亚铁并接种AMF显著地提高了土壤有效铁、锰含量,降低了土壤中水溶性砷、磷含量以及玉米地上部砷的含量,并极大地增加了植株对磷的吸收,提高了植株体内磷砷吸收量之比,从而明显地改善了植株的菌根建成和生长状况.在不接种情况下,硫酸亚铁和石灰混合处理显著地降低了土壤水溶性砷、磷含量及根系砷含量,并明显增加了磷的吸收以及磷、砷吸收量的比值,使玉米植株生物量和根长增加的幅度较其它铁源处理时更大.尽管添加铁尾矿砂增加了土壤水溶性磷的含量以及植株磷的吸收而在一定程度上改善了玉米的生长,但这种效果以不接种时更为明显,因而有必要根据土壤的污染程度调整铁尾矿砂的添加量和接种抗性菌株,以强化植物的抗砷能力.

Ferrous mining tailings in combination with arbuscular mycorrhizal fungus （AMF） Glomus mosseae could be used to reclaim arsenic （As） contaminated soils. Growth and nutrient uptake by maize plants （ Zea mays L. ） grown in pots of the contaminated soil were measured. The results showed that ferrous sulfate addition and mycorrhizal inoculation （Myc） significantly increased soil-available Fe and Mn concentrations, and greatly increased P uptake and uptake ratios of P to As in plants, but decreased water-extractable P and As concentrations in soil and As concentration in maize shoots, therefore this treatment obviously enhanced plant growth and mycorrhizal colonization. For plants which were not inoculated with the fungus, addition of ferrous sulfate and lime markedly decreased water-extractable P and As concentrations in soil and As concentration in maize roots, but increased P uptake and P/As ratios in plants, which resulted in the highest plant biomass and root length among the different iron addition treatments. Addition of iron mining tailings also slightly enhanced plant growth of uninoculated maize plants through increasing soil water-extractable P concentrations and plant P uptake. In order to maximize the positive effects of ferrous sources and mycorrhizal fungi on plant adaptation to As contamination, further work is necessary to optimize the addition regime and to isolate AMF strains with As tolerance.