稀土元素钕对铜绿微囊藻生长和生理特性的影响

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。

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

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.