稀土铈对水华鱼腥藻生理特性及藻毒素释放的影响

随着稀土及其化合物的广泛应用,越来越多的稀土直接或间接进入水体,因而稀土对水生生态环境的影响备受关注。采用室内模拟试验,研究不同浓度（0~10.00mg·L-1）的稀土元素铈（Ce3＋）对水华鱼腥藻的影响,绘制了水华鱼腥藻的生长曲线,测定了藻蓝蛋白、类胡萝卜素、可溶性蛋白含量和过氧化物酶（POD）活性4项生理指标,以及培养基中总磷（TP）、微囊藻毒素-LR（MC-LR）的浓度。结果表明,和其他各组相比,在0.10mg·L-1Ce3＋处理下,水华鱼腥藻的生存量最为显著（P=0.008）,同时营养元素P被吸收后,培养基中残留的TP浓度达到最低值（1.52mg·L-1）。藻蓝蛋白、类胡萝卜素、可溶性蛋白含量和POD活性均随着Ce3＋浓度的升高呈现出先升高后降低的趋势。MC-LR在所有培养基中含量均较低,低于世界卫生组织（WHO）标准1.00μg·L-1。铈元素胁迫水华鱼腥藻产生的＂低促-高抑＂的Hormesis效应显著。

Effects of Cerium on Physiological Characteristics and Microcystins Release of Anabaena flos-aquae

Rare-earth and its compounds have been widely used in various fields resulting in potential environmental pollutions, especially in water body. Thus, many more attentions have been given in recent year on water pollutions from rare-earth applications. In this paper, the ef- fects of different initial Ce3＋ concentration（0~10.00 mg·L-1）on Anabaena flos-aquae were investigated in the simulated solutions in lab. The growth curve of Anabaena flos-aquae was plotted, and the physiological characteristics including the contents of phycocyanin, carotenoids, soluble protein and the activity of peroxidase（POD）were determined. Meanwhile, the concentrations of total phosphorus（TP）and microcys- tic toxins（MC-LR）in culture medium also were measured. The results showed that, the survived quantity of Anabaena flos-aquae was signif- icant comparing with other groups（P=0.008）when the concentration of Ce3＋ was 0.10 mg·L-1, and the residual TP in culture medium reached the lowest value（1.52 mg·L-1）due to the utilization of P by Anabaena flos-aquae. The mentioned four physiological indexes appeared a simi- lar trend with the increasing of Ce3＋ concentration, they all increased initially with a subsequent decrease. When the concentration of Ce3＋ was 0.10 mg·L-1, the contents of phycocyanin, soluble protein and the activity of POD reached highest. However, the contents of carotenoids could reach the highest value with the Ce3＋ concentration of 0.50 mg·L-1. The content of MC-LR was lower than the World Health Organization Standard（1.00 μg·L-1）in all culture medium. Thus, the effects of cerium on Anabaena flos-aquae typically presented as the＂Hormesis＂ef- fect.