盐胁迫对狐尾藻种苗生理指标及吸附Pb(Ⅱ)的影响

Effects of salt stress on physiological indicators and adsorption ability for Pb( Ⅱ) of Myriophyllum verticilatum seedling

以狐尾藻种苗为研究对象,考察了不同盐度条件下其部分生理指标响应及对Pb^(2+)的吸附能力。结果显示,盐度在4‰以上,叶绿素含量随盐度增加而呈下降趋势,但其丙二醛含量却逐渐上升,较高盐度会加剧对狐尾藻种苗体内细胞膜的氧化破坏。然而,在0.9‰~14‰范围内,随盐度的增加,POD比活力、SOD总活力、根系活力等均表现出先上升后下降的相似趋势。另外,狐尾藻种苗对营养液中Pb^(2+)的吸附行为较符合伪二级动力学方程,其存在界面扩散、表面活性反应位点的离子交换、内扩散等三个过程,而且,水体的高盐度会削弱狐尾藻种苗对Pb^(2+)的吸收能力。

In order to explore the effects of salt stress on physiological response and adsorption ability for Pb2＋ of Myriophyllum verticilatum seedling, in this paper, Myriophyllum verticilatum seedlings were cultivated in Hoagland nutrient solutions which were imposed to six levels of salinities （0. 9%cy 2%cf 4%cf l%cf 10%c, I4%c NaCl） , then, five physiological indicators and removal rates of Pb2＋ in Hoagland nutrient solutions related with salt hardiness were measured, and the adsorption mechanism was investigated by model simulation. The results showed that leaf chlorophyll content reduced when salt concentrations were elevated, but malondialdehyde（ MDA） content increased with increasing salt concentration, when above the salinity of A%cJ high salinity was thought to intensify oxidative damage to the cell membrane of Myriophyllum verticilatum seedling. While the activities of POD, SOD, root peaked at some concentration and then dropped gradually, when salinities were in the range of 0. 9%c -14%c. Besides that, the mechanism for Pb2＋ adsorption on Myriophyllum verticilatum seedlings was further discussed. For single Pb2＋ solution, adsorption process could fit well with the pseudo - second - order kinetic equation, which included three processes such as interface diffusion process, ion exchange process in surface active reaction sites, and intra - particle diffusion process. Moreo-ver, high salinity would weaken the absorption ability for Pb2＋ of Myriophyllum verticilatum seed-lings.