3种挺水植物对污水的净化效果及生理响应

Physiological Response of Emergent Hydrophytes to Wastewater Stress and Their Potential for Reducing COD and Nutrients

为了探明宽叶香蒲(Typha latifolia L.)、茭白(Zizania latifolia Turcz.)及黄花鸢尾(Iris pseudacorus L.)在人工湿地污水处理系统中的抗逆性和适应性,采用人工模拟方法,设置4个处理,分别为:T_0(15 mg·L^(-1) COD,0.2 mg·L^(-1) TN,0.02mg·L^(-1) TP)、T_1(80 mg·L^(-1) COD,15 mg·L^(-1) TN,2 mg·L^(-1) TP)、T_2(160 mg·L^(-1) COD,30 mg·L^(-1) TN,4 mg·L^(-1) TP)和T_3(320 mg·L^(-1) COD,60 mg·L^(-1) TN,8 mg·L^(-1) TP),研究这3种植物对不同浓度污水的净化能力及其抗性生理特征。结果表明,宽叶香蒲、茭白及黄花鸢尾对T_1、T_2、T_3污水中的COD、TN和TP均有较高的净化率。同一浓度污水处理下,各植物对COD的去除效果均无显著差异,黄花鸢尾对TP的去除效果最好,茭白对TN的去除效果表现最佳。T_1污水处理没有增加3种植物的丙二醛(MDA)含量,随着污水浓度的升高,T_2、T_3污水处理下3种植物MDA含量明显上升,表明污水浓度的增加引起3种植物体内膜脂过氧化加剧。此外,污水胁迫也导致了3种植物体内的抗氧化酶活性和脯氨酸含量的变化。茭白的超氧化物歧化酶(SOD)和宽叶香蒲的过氧化物酶(POD)可能在其自由基的清除中发挥重要作用,SOD和过氧化氢酶(CAT)的协同作用代表了宽叶香蒲和黄花鸢尾抵抗污水胁迫的一种防御策略,黄花鸢尾体内脯氨酸的积累可能在其抵抗污水胁迫中扮演着重要角色。综上,宽叶香蒲、茭白和黄花鸢尾对不同污染负荷水体均有较高的净化效果,通过调节抗氧化酶系统和脯氨酸的合成来减少逆境胁迫引起的氧化伤害,高污染负荷水体对3种植物有胁迫作用。

In order to study the ability of hydrophytes in purifying polluted water and plant responses to oxidative stress induced by chemical oxygen demand（COD）, nitrogen and phosphorus, three macrophytes species（Zizania latifolia Turcz., Iris pseudacorus L. and Typha latifolia L.） were treated with various concentrations of COD/TN/TP（T0： 15/0.2/0.02 mg·L-1, T1： 80/15/2 mg·L-1, T2： 160/30/4 mg·L-1 and T3： 320/60/8 mg·L-1）. The results showed that vegetated microcosms were more effective at reducing concentrations of COD, total nitrogen（TN） and total phosphorus（TP） than unvegetated. There is a differential species effect on the potential to reduce TN and TP. Z. latifolia was most effective in terms of TN removal, while I. pseudacorus showed the highest TP removal efficiency. However, there was no significant difference between vegetated microcosms for COD removal efficiencies. The MDA levels of I. pseudacorus and T. latifolia were not increased exposed to sewage, which was associated with significantly higher SOD and CAT activities in plants treated with T1. POD in T. latifolia, SOD in Z. latifolia and free proline in I. pseudacorus might play important roles against oxidative stress. However, treatment with high COD/N/P（T2, T3） significantly increase the MDA levels of three hydrophytes. It can be concluded that the antioxidative defense system and free proline accumulation were activated but could not resist the oxidative stress in plants exposed to high concentrations of COD/N/P（≥160/30/4 mg·L-1）.