3种地衣体内藻类对4种重金属离子的耐受能力及其吸附特性研究

Study on Characteristics of Tolerance and Absorption of Four Heavy Metals by Three Photobionts

该研究以地衣体内分离培养的3种共生藻体(A、B、C)为材料,采用光学显微镜徒手切片技术,测定地衣体内藻细胞存活率;并采用BCO和双硫腙、二甲酚橙和碘化钾-罗丹明B分光光度法,测定培养液和藻体内不同重金属含量,分析3种共生藻体对重金属Cu^2+、Zn^2+、Pb^2+、Cd^2+的吸附特性及其耐受性差异,以明确地衣与重金属胁迫的关系,为重金属污染水体的生物修复提供理论依据。结果显示:(1)在不同重金属胁迫下,3种藻体对4种重金属的耐性大小均表现为Zn^2+>Pb^2+>Cu^2+>Cd^2+,重金属对3种藻体的毒性大小依次是Cu^2+(藻体B>藻体A>藻体C)、Zn^2+(藻体B>藻体A>藻体C)、Pb^2+(藻体B>藻体A>藻体C)、Cd2+(藻体B>藻体C>藻体A)。(2)3种藻体对Zn^2+、Pb^2+的吸附性均高于Cu2+和Cd2+,而且藻体B对不同重金属的吸附性能均高于藻体A和C。(3)3种藻体所吸附的重金属含量与其胁迫浓度及培养时间均呈极显著正相关关系(P<0.01),3种藻体对重金属的耐受性与吸附性呈正相关关系。研究发现,来自地衣体的3种藻体对Cu^2+、Zn^2+、Pb^2+和Cd^2+的耐受性和吸附性远远高于一些自由生长藻类,证明来自地衣体的藻类是修复重金属污染生物吸附剂的良好材料,该研究结果为地衣体内藻在水体重金属污染生物修复中的实际应用提供了理论依据。

In this study, three photobiont (A, B, C) isolated and cultured in the lichens were used as research materials. The light microscopy, BCO, dithizone, xylenol orange and Potassium iodide-rhodamine Bspectrophotometric met-hod were used to determine the cell viability of photobiont, different heavy meatal contents in culture medium and photobiont. The absorption characteristics and tolerance of three photobionts to heavy metal Cu^2+, Zn ^2+, Pb ^2+ and Cd ^2+ were analyzed to determine the relationship between photobiont and heavy metal stress, and to provide a theoretical basis for bioremediation of heavy metal polluted water. The results showed that:(1) under the different concentrations of heavy metal stress, the tolerance of three photobionts to four heavy metals:Zn^ 2+>Pb^ 2+>Cu ^2+>Cd^ 2+ and heavy metal toxicity of different photobionts: Cu^ 2+(B> A >C),Zn 2+(B > A >C),Pb ^2+(B > A >C), Cd ^2+(B > C > A).(2)All of the photobionts adsorbability of Zn ^2+ and Pb ^2+ was higher than that of Cu^ 2+ and Cd 2+, and the absorption of algal B to different heavy metals was higher than that of A and C.(3) All of the photobionts was positive correlated with cell absorption and tolerant concentration and different culture time points ( P <0.01), and the tolerance of the two algal species to heavy metals was positively correlated with their absorption. The study found that the photobionts have a better tolerance and absorption to heavy metals than some free-growing algae, will be a good material for remediation of heavy metal contaminated biosorbents, and the results of this study provide a theoretical basis for the practical application of photobiont in the bioremediation of water and metal pollution.