4种植物对水体中苯的净化效果及其抗性响应

摘要

以植物修复理论为基础,探寻对含苯废水具有较强耐受能力和较好净化效果的植物种类,为城市污水净化和河道绿化提供新型的植物材料.利用菊芋(Helianthus tuberosus L.)、旋覆花(Inula japonica Thunb.)、千屈菜(Lythrum salicaria L.)和红蓼(Polygonum orientale L.)4种耐水湿观赏植物为修复材料去除水体的苯,对其净化苯的效果进行了测定和比较,同时从生长状况和生理指标方面探讨了4种植物在苯胁迫下的抗性响应,包括生长量、细胞伤害指标、抗氧化酶、渗透调节物质和光合作用指标的变化.结果表明,处理30 d后4种植物对1.75 g·L-1苯的去除能力大小顺序为红蓼(78.22%)>菊芋(59.83%)>旋覆花(26.94%)>千屈菜(21.14%).此外,苯胁迫对植物生长有一定的抑制作用,但是植物可以通过体内保护酶体系和渗透调节能力来抵御苯的胁迫,使其保持或恢复正常的叶绿素水平、光合能力,防止细胞因膜质过氧化程度加剧而受到伤害,4种植物对苯的耐受能力顺序为红蓼>菊芋>千屈菜>旋覆花;抵御苯胁迫时酶体系保护能力强弱顺序为红蓼>菊芋>千屈菜>旋覆花;通过渗透调节来抵御苯胁迫的能力大小为菊芋>红蓼>千屈菜>旋覆花;在苯胁迫下保持和恢复光合作用能力的大小顺序为红蓼>菊芋>旋覆花>千屈菜.总之,4种植物均对水体中的苯毒物具有较强的耐受能力和明显的净化效果,在现代城市污水综合治理及污水河道绿化中具有应用潜力,可以在水体环境工程实践中进一步研究.%On the basis of phytoremediation theory, our study aims to find plants with strong endurance and purifying capability to polluted water rich in benzene. In this study, we chose four ornamental plants, including Helianthus tuberosus L., Inula japonica Thunb.,Lythrum salicaria L.and Polygonum orientale L.,as our experimental materials.We cultivated these plants by water with benzene concentration about 1.75 g·L-1for 30 days. Then, we adopted three indicators (antioxidant enzymes content, material content for osmotic balance, photosynthetic rate) to quantify the endurance of plants to benzene, and further investigated the percent of removal benzene in water of plants to reflect the purifying capability of plants to benzene. Our results showed that the plant with strongest endurance to benzene was Polygonum orientale L., followed by Helianthus tuberosus L., Lythrum salicaria L. and Inula japonica Thunb. (the order of antioxidant enzymes content: Pplygonum orientale L.>Helianthus tuberosus L.>Lythrum salicaria L.>Inula japonica Thunb.;the order of material content for osmotic balance:Helianthus tuberosus L.>Pplygonum orientale L.>Lythrum salicaria L.>Inula japonica Thunb.; the order of photosynthetic rate: Polygonum orientale L.>Helianthus tuberosus L.>Lythrum salicaria L.>Inula japonica Thunb.). This indicated that although biomasses of the four species of plants were restrained, their protective enzymes and osmotic adjustments played actively roles in resisting benzene threat to maintain and recover normal level of chlorophyll content, photosynthetic rate and cell status. Besides that, our results also showed that the plant with strongest capability of benzene purification was Polygonum orientale L.(78.22%),followed by Helianthus tuberosus L.(59.83%), Inula japonica Thunb. (26.94%) and Lythrum salicaria L.(21.14%). Through our study, we find that all of these four ornamental plants have endurance and purifying capability to polluted water rich in benzene, suggesting that these plants have potential to be used as new materials for benzene removal in polluted water and make contributions to urban environmental management.