摘要
采用改进的常规耗竭法研究了6种蔬菜型湿地植物根系对氮、磷营养盐的吸收特征及差异。这6种植物根系对NH_4^+-N、NO_3^--N和H_2PO_4^-的吸收动力学特征均可采用Michaelis-Menten方程描述。结果表明:不同植物对氮、磷的最大吸收速率I_(max)和最小亲和力K_m有显著差异。6种植物对NH_4^+-N的吸收速率最大,对H_2PO_4^-的亲和力常数较小,所以当水体中氮、磷浓度较低时,优先选择吸收磷,但对铵态氮的吸收速率最快。通过对6种植物根系吸收氮、磷的最大吸收速率I_(max)和亲和力常数K_m的比较可知,空心菜根系拥有最大的I_(max)和最小K_m,说明空心菜能够适应任意浓度的水体净化,芋头I_(max)较低而K_m较大,说明芋头不适宜作为生态修复植物;韭菜适合高氮、磷水平的水体净化,可用作水体修复中的先锋植物,生菜适合低氮、磷水平的水体净化;雪里蕻适宜用于低P、低NH_4^+-N、高NO_3^--N水体修复,金花菜则是对高P、高NH_4^+-N、低NO_3^--N水平的污染水体处理效果相对较好;但考虑食用安全性问题,重金属含量可能超标,工程应用时需谨慎。
The nitrogen and phosphorus uptake kinetics of six kinds of aquatic vegetables＇ root system were investigated by using the modified depletion method.The NH_4＋-N,NO_3--N and H_2PO_4- uptake kinetics of the six plants＇ root systems could be expressed with the Michaelis-Menten equation.Results showed that the maximum uptake rate（I_（max）） and the Michaelis-Menten constant（K_m） was significantly different between the six plants＇ root systems.The six kinds of aquatic vegetables in wetland had higher I_（max）for NH_4＋-N and less K_mfor H2PO-4.In condition of low nitrogen and phosphorus concentration wastewater,the plants preferred absorbing phosphorus,but the absorption rate of NH_4＋-N was fastest.Ipomoea aquatica Forsk ＇root system owned the maximum I_（max）and minimum K_m,which was suitable for treatment of all levels of polluted water.Colocasia esculenta L.Schoot.had lower I_（max）and higher K_m,which showed that Colocasia esculenta L.was not suitable for ecological rehabilitation.A.tuberosum Rottl.ex Spreng should be selected as pioneer plant to purify polluted water with high level of nitrogen and phosphorus and Lactuca sativa Linn.was proper to purify polluted water with low level of nitrogen and phosphorus.Brassica juncea var.was more fit for low H_2PO_4-,NH_4＋-N and high NO_3--N concentration wastewater purification,while Medicago hispida Gaertn.was applicable to repair polluted water with high H_2PO_4-,NH_4＋-N and low NO_3--N concentration and inedible.While take the safety of vegetable into consideration,the heavy metal concentrations could overstep the standard,so engineering application need more careful.
出处
《环境工程学报》
CAS
CSCD
北大核心
2017年第5期2828-2835,共8页
Chinese Journal of Environmental Engineering
基金
国家水体污染控制与治理科技重大专项(2012ZX07101-005)
关键词
水生蔬菜
水生植物
吸收动力学
富营养化
污染水体净化
aquatic vegetables
water plant
absorption kinetic
eutrophication
purification of polluted water
