不同污染负荷下浮水植物对水体营养盐的去除及生理响应

摘要

为了阐明在不同污染负荷下,水生植物对水体氮、磷、钾等营养盐的削减效果及不同营养水平下的生理响应,选用水质净化力强的漂浮植物水浮莲和水葫芦,探讨其对污水处理厂一级 A 达标排放尾水中氮、磷、钾的去除效果及此过程中水生植物的生理生态学变化.结果表明,尾水经过总长80m 的水浮莲和水葫芦组合配置的净化塘后,水体 TN、TP、TK 分别由初始的11.97,1.69,8.10mg/L 削减至5.23,1.10,4.73mg/L.随着水体营养盐浓度的逐渐降低,水浮莲和水葫芦根冠比均有显著增加,水浮莲茎叶叶绿素 a 含量明显降低,叶片微黄,而水葫芦叶绿素a含量变化不大.2种漂浮植物根系中与氮、磷、钾等营养盐相关的硝酸还原酶(NR)、Na+-K+ATP酶、H+-K+ATP酶均与水体氮、磷、钾浓度负相关,当环境中浓度营养盐浓度较低时,水生植物可通过提高根系中相关酶活性,满足自己对营养的高效吸收与利用.而水浮莲根系的碱性磷酸酶(AKP)活力与水体氮、磷、钾浓度呈正相关.其中水葫芦根系的 Na+-K+ATP 酶和 H+-K+ATP 酶相比于初始值分别提高了88.92%和103.20%.%In order to illustrate nutrient removal and physiological response of aquatic macrophytes under different pollution loads, water lettuce and water hyacinth were selected to study on their water purification characteristics, physiological and biochemical response to tailrace of sewage. TN, TP and TK concentrations reduced from 11.97, 1.69, 8.10mg/L to 5.23, 1.10, 4.73mg/L when the sewage run through the purification pond cultured with water lettuce and water hyacinth alternately. With nutrient concentration decreasing in sewage, leaves turn yellow, chlorophyll a content in stems and leaves of water lettuce decreased significantly, while no significant changes on chlorophyll a content of water hyacinth were found. A significant negative correlation existed between NPK concentration in sewage and nitrate reductase, Na+-K+ATPase, H+-K+ATPase in roots of macrophytes. The enzyme activity of aquatic plants may be improved to meet with their efficient nutrition absorption when nutrient concentration is low in the environment. While AKP in water lettuce roots appeared positive correlation with NPK concentration in sewage. Compared with the beginning, Na+-K+ATPase and H+-K+ATPase of water hyacinth increased by 88.92% and 103.20%, respectively.