丛枝菌根真菌对人工湿地植物生长及水质净化的影响研究

Effects of Arbuscular Mycorrhizal Fungi on Plant Growth and Water Purification in Constructed Wetlands

丛枝菌根真菌(AM真菌)是湿地植物的主要共生菌,可以强化植物对养分的吸收、促进植物的生长,是一种潜在的提高人工湿地污染物去除效率的微生物,然而目前关于AM真菌在实际人工湿地中应用及其效果评价的研究较少。鉴于此,在北京某人工湿地进行了现场实验,以水葱、黄菖蒲两种湿地植物为对象并分别施加AM真菌菌剂,考察了植物菌根侵染状况,植物株高、根长、鲜物质量等植物生长指标以及COD、氨氮、TP浓度等水质指标;基于AM真菌接种与未接种区域的各指标差异,探讨了接种AM真菌对人工湿地植物生长和水质净化的影响。结果表明:2种湿地植物(水葱、黄菖蒲)均能与AM真菌建立良好的共生关系,接种AM真菌后,植物根系中的菌根侵染率和菌根侵染强度均得到了显著提高(P>0.05),水葱和黄菖蒲的菌根侵染率分别达到了37.67%和23.91%;接种AM真菌显著提高了植物的株高、根长、鲜物质量(P>0.05),分别提高了17.79%—31.35%、18.79%—29.14%、54.56%—116.43%;与未接种组相比,接种AM真菌提高了人工湿地对COD、氨氮、TP的去除,污染物去除分别提高了12.32%—24.19%、5.45%—45.31%、5.30%—57.06%;污水原水质状况属于劣V类,经人工湿地处理6个月后,实验区域水体的COD浓度、氨氮浓度以及TP浓度均达到了地表水Ⅲ类水质标准。研究表明:接种AM真菌促进了人工湿地植物的生长,且对水质净化起到了积极作用。该研究结果揭示了在实际运行人工湿地中丛枝菌根真菌对湿地植物生长和水质净化的影响,可为中国人工湿地的高效运行提供理论依据和技术支持。

Constructed wetland is a kind of water treatment system which is widely used. Arbuscular mycorrhizal fungi(AM fungi) is the main symbiotic fungi of wetland plants, which can increase the uptake of nutrients by plants and thus promote their growth.Therefore, AM fungi is a promising microorganism to improve the removal efficiency of pollutants in constructed wetlands. However,few studies focused on the application of AM fungi in actual constructed wetlands. Therefore, a field experiment was conducted in a constructed wetland of Beijing. Two wetland plants, Scirpus tabernaemontani and Iris pseudacorus, were treated with an AM fungal inoculum, respectively. The plant mycorrhizal infection rate, plant height, root length, fresh weight, COD concentration, ammonia nitrogen concentration and total phosphorus concentration(TP) were investigated. Based on the differences of these indicators between the inoculated and non-inoculated areas, the effects of AM fungi inoculation on plant growth and water purification in constructed wetland were discussed. The results showed that the two wetland plants(Scirpus tabernaemontani and Iris pseudacorus) could establish a good symbiotic relationship with AM fungi. The mycorrhizal infection rate and mycorrhizal infection intensity in plant roots were significantly increased(P>0.05) with the inoculation of the AM fungi, and the mycorrhizal infection rates of Scirpus tabernaemontani and Iris pseudacorus were 37.67% and 23.91%, respectively. Inoculation of AM fungi significantly increased the plant height, root length, and fresh weight(P>0.05) by 17.79%–31.35%, 18.79%–29.14%, 54.56%–116.43%, respectively. Compared with the noninoculated group, the inoculation of AM fungi improved the removal of COD, ammonia nitrogen and TP, and the pollutant removal efficiencies were relatively increased by 12.32%–24.19%, 5.45%–45.31% and 5.30%–57.06%, respectively. The original water quality of the wastewater was classified as the inferior V. After six months of treatment with constructed wetland, the water concentration of COD, ammonia nitrogen and TP in the experimental reached water quality standard of Class Ⅲ for surface water. The results showed that inoculation of AM fungi was able to promote the growth of plants and water purification efficiency in constructed wetland. The results of this study revealed the effects of arbuscular mycorrhizal fungi on plant growth and water purification efficiency in the constructed wetlands. The findings could support the efficient operation of constructed wetlands in China.