淡水环境下3种红树植物对氮磷的去除效应应

2010年7 ~ 12月，通过水培盆栽试验研究了桐花（Aegiceras corniculatum）、海莲（Bruguiera sexangula）和无瓣海桑（Sonneratia caseolaris）对生活污水的净化效果，设置了3个浓度梯度，即N1P1（TN 为3.96 mg• L-1，TP为 0.47 mg• L-1），N2P2（TN为 19.8 mg•L-1，TP 为2.35 mg•L-1）和N3P3（TN为 39.6 mg•L-1，TP为 4.7 mg•L-1）。研究结果表明：随着水培时间的增加，水体盐度、总氮和总磷含量显著下降（P <0.001）。桐花、海莲和无瓣海桑对生活污水总氮去除率达74.5% ~ 97.4%，总磷去除率达72.3% ~ 95.7%。栽培有红树植物的系统对氮磷的去除率显著高于无植物系统，分别为无植物的1.28倍 ~ 3.2倍和1.24倍 ~ 2.71倍。红树植物氮磷质量分数分别为6.81 mg•g-1±0.85 mg•g-1 和 1.41 mg•g-1±0.46 mg•g-1。当污水浓度低时（N1P1），红树植物主要是通过累积作用去除水体氮磷，占总去除效应的42.2% ~ 63.3%和46.1% ~ 85.8%。当污水浓度高时（N3P3），红树植物氮磷累积量仅占4.5% ~ 10.4%和6.7% ~ 14.9%。

Removal Efficiencies of Nitrogen and Phosphorus by Three Mangrove Plants Under Freshwater

Removal efficiencies of domestic sewage by Aegiceras corniculatum, Bruguiera sexangula, and Sonneratia caseolaris were investigated by method of potted experiment under the different hydroponic culture conditions from July to December in 2010. The N1P1 represented the content of total nitrogen (TN) for mg•L-1 and total phosphorus (TP) for 0.47 mg•L-1. The N2P2 represented the content of TN for 19.8 mg•L-1 and TP for 2.35 mg•L-1. The N3P3 implied the content of TN for 39.6 mg• L-1, TP for 4.7 mg•L-1. The results showed that the salinity, TN and TP in water rapidly declined with an increase of cultivation time (P <0.001). The removal efficiencies of TN and TP ranged from 74.5% to 97.4% and from 72.3% to 95.7% by A. corniculatum, B. sexangula and S. caseolaris. The removal rates of TN and TP in the planted pots were 128%~320% and 124%~271% as high as those in unplanted pots. The contents of total N and total P in mangrove plants ranged from 5.18 mg•g-1 to 9.64 mg•g-1 with an average of 6.81 mg•g-1 and from 0.74 mg•g-1 to 2.98 mg•g-1 with an average of 1.41 mg•g-1, respectively. The plant nitrogen and phosphorus assimilation played an important role for nutrient removal under the culture condition of the N1P1, and the contribution rates on the TN and TP removal ranged from 42.2% to 63.3% and from 46.1% to 85.8%, respectively. However, the TN and TP removal by plant absorption were rather small under the N3P3, accounting for 4.5%~10.4% and 6.7%~14.9%, respectively.