满江红-鱼腥藻对低浓度铀胁迫的适应机制

The Mechanism for Adaptation of Azolla Anabaenato Be Stressed by Low Concentration Uranium From Wastewater

通过采用不同铀浓度的废水对满江红-鱼腥藻进行水培,分析铀在满江红-鱼腥藻亚细胞中的分布和各种化学形态的铀的比例,研究满江红-鱼腥藻适应低浓度铀胁迫的机制。结果表明:87.9%~93.8%的铀主要固持于满江红-鱼腥藻的细胞壁中,阻滞了铀进一步进入胞内;随着水培溶液中铀质量浓度由0.5mg/L升高至3.0mg/L,胞内生物毒性较大的乙醇提取态铀和去离子水提取态铀所占比例之和由60.3%下降至56.4%,而毒性较小的醋酸提取态铀等所占比例之和由39.7%上升至43.6%,这有利于满江红-鱼腥藻在铀胁迫下的生长。细胞壁固持和铀的化学形态的转化是满江红-鱼腥藻适应铀胁迫的重要机制。

To investigate the mechanism for the adaptation of Azolla-Anabaena to be stressed by low concentration uranium from the wastewater,hydroponic culture experiments were carried out with different uranium mass concentration treatments(0.5,1.0,3.0 mg/L),and the subcellular distribution and chemical species of uranium in Azolla-Anabaena were analyzed.The results show that uranium is mainly distributed in the cell walls of Azolla-Anabaena,accounting for 87.9%~93.8%,which indicated that the cell walls can effectively prevent uranium from accessing into the cells.The total proportion of ethanol and water extractable forms is decreased from 60.3%to 56.4%,however the less toxic uranium species is increased from 39.7%to 43.6%with the increasing of uranium mass concentration from 0.5 mg/L to 3.0 mg/L,and this is beneficial to the growth of Azolla-Anabaena under the uranium stress.Therefore,cell wall binding and chemical species transformation are the main mechanism for Azolla-Anabaena s adaptation to the stress of the low level uranium from wastewater.