稀土元素钕对铜绿微囊藻生长和生理特性的影响

Effects of Neodymium on the Growth and Physiological Characteristics of Microcystis aeruginosa

通过模拟培养试验,研究了不同Nd3+初始浓度条件下铜绿微囊藻(Microcystis aeruginosa)的生长及生理变化。结果表明,相对BG11培养基(Nd3+初始浓度为0 mg.L-1),低初始Nd3+浓度(0.01、0.05、0.1、0.5、1 mg.L-1)条件下,随着Nd3+浓度的增加,藻细胞中叶绿素a含量、可溶性蛋白含量和过氧化氢酶(CAT)活性均呈增加趋势,促进了铜绿微囊藻生长;在Nd3+初始浓度为5 mg.L-1和10mg.L-1时,藻细胞丙二醛(MDA)含量急剧增加,CAT活性下降,藻细胞清除活性氧(ROS)能力下降,抗氧化防御体系被破坏,膜脂过氧化严重,严重抑制藻细胞生长,在初始Nd3+浓度50 mg.L-1胁迫下,铜绿微囊藻无法生长。藻细胞超微结构表明,过量的Nd3+破坏了藻细胞内的类囊体结构,胞内脂质体含量增加,细胞膜变粗糙甚至变形破碎,对藻细胞造成不可逆伤害。

To investigate the effect of neodymium on Microcystis aeruginosa,the growth and physiological changes had been studied under different initial Nd3＋ concentration by lab cultured experiments.The results showed that,compared with the contro（lNd3＋-free）,the content of chlorophyll a（Chl-a）、soluble protein and the enzymatic activity of catalase（CAT）increased when initial Nd3＋ concentration changed from 0.01 mg.L-1 to 1 mg.L-1,and the growth of Microcystis aeruginosa was stimulated;However,under 5 mg.L-1 and 10 mg.L-1 initial Nd3＋ con-centration,the content of malon-diadehyde（MDA）increased immediately but the enzymatic activity of catalase（CAT）reduced,which result-ed in the decline of the Microcystis aeruginosa′s ability to eliminate the active oxygen and the ruin of antioxidant defense system,and the growth of Microcystis aeruginosa slowed down.Finally,while the initial Nd3＋ concentration was 50 mg.L-1,Microcystis aeruginosa couldn′t grow anymore.The ultrastructure of Microcystis aeruginosa showed that excessive Nd3＋ could lead to the decrease of thylakoid and the in-crease of fat particle,and the cell membrane became rough and even broken,which caused irreversible damage to algal cells.