苦草对重金属去除效果的对比及其叶绿素荧光特性响应

Study on heavy metal removal efficiency and chlorophyll fluorescence response of Vallisneria natans

比较在低、中、高3种浓度水平下苦草(Vallisneria natans)对Cu^(2+)、Zn^(2+)、Cd^(2+)、Pb^(2+)4种重金属离子的去除效果及其叶绿素荧光参数的响应,结果表明:(1)在4种重金属中苦草对Cu^(2+)的去除效果最好,对Zn^(2+)的吸收量最高。苦草对Cu^(2+)、Zn^(2+)、Cd^(2+)、Pb^(2+)的最高吸收量分别为4.21、25.3、0.231、0.509μg/g,Cu^(2+)的中质量浓度组衰减比最高(47.33%),Zn^(2+)、Cd^(2+)、Pb^(2+)均为低质量浓度组衰减比最高,分别为33.13%、29.2%、45.7%;(2)重金属胁迫下,Cu^(2+)、Zn^(2+)高质量浓度组中苦草叶绿素a含量比Cd^(2+)、Pb^(2+)高质量浓度组下降幅度小,叶绿素b含量下降幅度则为Zn^(2+)>Cu^(2+)>Cd^(2+)>Pb^(2+),高质量浓度组下降幅度大。(3)苦草最大光化学效率(F_(v)/F_(m))、潜在光化学效率(F_(v)/F_(0))在Cu^(2+)、Zn^(2+)胁迫下有不同程度的升高,而在Cd^(2+)、Pb^(2+)胁迫下均显著下降。光化学淬灭系数(Q_(p))、非光化学淬灭效率(Q_(n))和调节性能量耗散的量子产量(Y_(NPQ))均随重金属质量浓度升高而下降,其中Zn^(2+)、Cu^(2+)、Cd^(2+)、Pb^(2+)各质量浓度组Q_(p)下降幅度依次减小,而有效量子产量(YⅡ)随重金属质量浓度升高而升高。总体而言,苦草更适合用于去除水体中的Cu^(2+)、Zn^(2+),研究结果为重金属污染河道生态修复奠定基础。

After comparing the removal effect of Vallisneria natans on Cu^(2+),Zn^(2+),Cd^(2+),Pb^(2+),and the responses of chlorophyll fluorescence parameters at low,medium and high concentration levels,our results showed that:(1)Among the four heavy metals,Vallisneria natans has the best removal effect on Cu^(2+)and the highest absorption of Zn^(2+).The maximum absorption of Cu^(2+),Zn^(2+),Cd^(2+)and Pb^(2+)by bitter grass were 4.21,25.3,0.231 and 0.509μg/g respectively,the attenuation ratio of the medium mass concentration group of Cu^(2+)was the highest(47.33%),and that of the low mass concentration group of Zn^(2+),Cd^(2+),Pb^(2+)was the highest(33.13%,29.2%,45.7%);(2)Under heavy metal stress,the chlorophyll a content of Vallisneria natans in the Cu^(2+)and Zn^(2+)high mass concentration groups decreased less than that in the Cd^(2+)and Pb^(2+)high mass concentration groups,and the order of the decrease in chlorophyll b content was Zn^(2+)>Cu^(2+)>Cd^(2+)>Pb^(2+),and the high mass concentration group decreased significantly.(3)The maximum photochemical efficiency(F_(v)/F_(m))and potential photochemical efficiency(F_(v)/F_(0))of Vallisneria natans increased in different degrees under Cu^(2+)and Zn^(2+)stress,but decreased significantly under Cd^(2+)and Pb^(2+)stress.The photochemical quenching coefficient(Q_(p)),non-photochemical quenching efficiency(Q_(n))and the quantum yield of regulatory energy dissipation(Y_(NPQ))all decreased with the increase of heavy metal mass concentration,in which the decrease of Q_(p)in Zn^(2+),Cu^(2+),Cd^(2+),Pb^(2+)mass concentration groups decreased in turn,while the effective quantum yield(YⅡ)increased with the increase of heavy metal mass concentration.In general,Vallisneria natans is more suitable for removing Cu^(2+)and Zn^(2+)in water.The research results may lay a foundation for the ecological restoration of heavy metal polluted rivers.