铀胁迫对两种蓝藻生长及抗氧化酶活性的影响

研究了不同浓度铀(0.1、1.0、10.0和30.0mg·L-1)胁迫对满江红鱼腥藻(Anabaena azollae)和爪哇伪枝藻(Scytonemaj avanicum)生长及抗氧化酶活性的影响。结果表明,低浓度铀(0.1和1.0mg·L-1)条件下,两种蓝藻的超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)活性及丙二醛(MDA)含量均无明显变化;叶绿素a含量和可溶性蛋白质含量均较对照上升,表明低浓度铀对A.azollae和S.javanicum均未形成明显胁迫,对生长表现为刺激和促进作用。10.0mg·L-1浓度的铀对A. azollae的生长影响不大,对S. javanicum却产生了明显的抑制作用。30.0mg·L-1铀胁迫下,两种蓝藻中的MDA显著增加,抗氧化酶系统受到破坏,生长严重受阻。实验结果显示,A. azollae和S. javanicum的耐铀极限分别在10.0～30.0mg·L-1和1.0～10.0mg·L-1之间,A. azollae的抗铀性比S. javanicum强。

Effects of Uranium Stress on Growth and Activity of Antioxidant Enzymes of Two Cyanobacteria

Effects of different uranium concentrations (0.1, 1.0, 10.0, and 30.0 mg·L^-1) on growth and activity of antioxidant enzymes of two cyanobacteria were studied. The chlorophyll a content, soluble protein content, malonaldehyde (MDA) content, activity of superoxide dismutase (SOD), catalase (CAT), peroxide enzyme (POD) were determined in Anabaena azollae and Scytonema javanicum. Under 0.1 and 1.0 mg L^-1 uranium stress, in two cyanobacteria, there were no obvious change occurred in the activity of antioxidant enzymes (SOD, POD, CAT) and MDA content, while the content of chlorophyll a and soluble protein increased slightly compared with the control group. These results suggested that low concentration uranium (0.1, 1.0 mg·L^-1) didn't cause evident stress on two cyanobacteria, yet, it could stimulate and promote the growth of two cyanobacteria. 10.0 mg·L^-1 uranium caused little stress on the growth of A.azollae but caused obvious inhibition on S.javanicum. Under 30.0 mg·L^-1 uranium stress, MDA content increased evidently, the antioxidant system was destroyed, the growth of two cyanobacteria was inhibited seriously. The limit resistance to uranium of A.azollae was in the range of 10.0~30.0 mg·L^-1, while S.javanicum was between 1.0 mg·L^-1 and 10.0 mg·L^-1, indicating that the tolerantce of A. azollae to uranium was stronger than that of S. javanicum.