重金属Cu^(2+)胁迫对半叶马尾藻生长及生理生化特性的影响

Effect of Cu^(2+) stress on growth and physiological biochemical characteristics of Sargassum hemiphyllum

采用半静态试验法研究了不同浓度的重金属铜离子(Cu2+)胁迫对半叶马尾藻(Sargassum hemiphyllum)生长及生理生化特性的影响。结果表明,对照组藻体相对生长速率(RGR)持续升高,胁迫组均先上升而后下降,实验第8天时只有ρ(Cu2+)为0.05 mg·L-1胁迫组的RGR较对照组高。藻体的各项生理生化指标随胁迫时间呈波动趋势,实验第8天时,ρ(Cu2+)为0.01 mg·L-1胁迫组的各项指标与对照组无显著差异;ρ(Cu2+)为0.05 mg·L-1时,过氧化氢酶(CAT)活性和丙二醛(MDA)水平显著高于对照组,其余指标均恢复到对照组水平;ρ(Cu2+)>0.05 mg·L-1的胁迫组,叶绿素a(Chl-a)、类胡萝卜素(Car)和可溶性蛋白(SP)水平低于对照组,其余指标高于对照组,同时相对于0.25 mg·L-1胁迫组,1.25 mg·L-1胁迫组对除MDA外的其余指标影响更显著。因此,适当质量浓度的Cu2+胁迫(≤0.05 mg·L-1)对半叶马尾藻生长和生理生化指标有正面效应,而过高质量浓度Cu2+胁迫(>0.05 mg·L-1)对藻体生长和抗逆能力有一定的负面影响。

We studied the effect of Cu2 ＋ stress at different concentrations on the growth and physiological biochemical characteristics of Sargassum hemiphyUum by a semi-static test for 8 d. The results show that the relative growth rate （RGR） of thalli in the control in- creased initially and then decreased with time; on the 8th day, the RGR of thalli was higher than that in the control only when Cu2＋ concentration was 0.05 mg.L-1. The physiological biochemical indices showed a fluctuation trend with time. On the 8th day, these in- dices of thalli at Cu2＋ concentration of 0. 01 mg.L-1had no significant difference with the control; when Cu2＋ concentration was 0. 05 mg.L-1, the catalase （CAT） activity and malondialdehyde （MDA） content were significantly higher than those in the control, and the other indices recovered to the control level. However, in Cu2＋ 〉 0. 05 mg.L-1 groups, chlorophyll a （Chl-a） , carotenoid （Car） and soluble protein （SP） were lower than those in the control; the other indices were higher than those in the control. Compared with 0. 25 mg.L-1 Cu2＋ group, 1.25 mg.L-1 Cu2＋ group had more significant influence on biochemical indices except MDA. Therefore, appropriate concentration of Cu2 ＋ （ ≤ 0.05 mg· L-1 ） had positive effect on the growth and physiological biochemical indices ofS. hemiphyllum, but there was negative impact on the growth and the ability of resilience of thalli when the concentration of Cu2＋ was extremely high （ 〉0. 05 mg.L-1 ）.