有机磷农药草甘膦异丙胺盐对球形棕囊藻的刺激效应

Hormesis effect of organophosphorus pesticide Glyphosate-isopropylammonium on Phaeocystis globosa

设置0、0.001、0.01、0.1、1和10mg·L-16个质量浓度梯度,测定了草甘膦异丙胺盐(Glyphosate-isopropylammonium)农药对球形棕囊藻(Phaeocystis globosa)生长、叶绿素a含量、SOD和CAT活性的影响,探讨了有机磷农药对球形棕囊藻的毒物刺激效应。结果表明,低浓度的草甘膦异丙胺盐对球形棕囊藻的生长呈现出刺激效应。在实验所设定的6个质量浓度梯度范围内,0.001mg·L-1和0.01mg·L-1质量浓度处理下的刺激效应最为显著。该两个质量浓度处理下,球形棕囊藻的平均相对增长率比对照分别提高了1.27%和0.45%,叶绿素a含量分别比对照提高了9.2%和2.5%,SOD活性提高了5.9%和7.2%,CAT活性提高了93%和155%;而当草甘膦异丙胺盐质量浓度在0.1mg·L-1以上时,球形棕囊藻的生长率、叶绿素a含量、SOD活性均显著低于对照。草甘膦异丙胺盐在0.001mg·L-1和0.01mg·L-1范围内对球形棕囊藻均呈现刺激效应,而高于0.1mg·L-1时球形棕囊藻各生理指标表现出显著抑制效应。研究结果为了解有机磷农药对海洋微藻生长的影响特征,揭示有机磷农药对微藻产生低促高抑的规律和为深入探索赤潮暴发的成因提供依据。

Setting up 6 different mass concentrations 0, 0.001, 0.01, 0.1, 1 and 10 mg.L-1 of Glyphosate-isopropylammonium, the growth rate, content of Chlorophyll-a and activities of two antioxidant enzymes （SOD, CAT） of red-tide species Phaeocystis globosa were measured in order to reveal the hormesis effect of organophosphorus pesticide. The results showed that lower concentration of Glyphosate-isopropylammonium simulated the growth of Phaeocystis globosa. In the 6 mass concentrations, comparing with control treatment, the effect of hormesis were the most obvious in the concentrations of 0.001 mg.L-1 and 0.01 mg.L-1. Under the treatments of those two mass concentrations, comparing with the control, the average relative growth rate ofPhaeocystis globosa was increased by 1.27% and 0.45%, chlorophyll-a by 9.2% and 2.5%, the activity of SOD by 5.9% and 7.2%, the activity of CAT by 93% and 155%. However, when the concentration was above 0.1 mg.L-1, the growth rate, content of chlorophyll-a and the activity of SOD were significantly lower than the control, indicating an effect of inhibition. The studies provided the basis to characterize the influ- ence of organophosphorus pesticide on Phaeocystis globosa and its laws of hormesis and toward a better understanding of the mechanism of red tide outbreaks.