塔胞藻及海水小球藻对草甘膦致毒胁迫的生理应答

摘要

The physiological effects of herbicide glyphosate on growth and synthesis of chlorophyll a were studied in algae Pyramidomonas delicatula and Chlorella saccharophila to alert the pesticide pollution severity in water environment and to reveal potential application of marine microalgae in environmental toxicological evaluation . The results showed that the glyphosate had no inhibitory effect on the alga grow th within the concentration in all experimental groups in the first 3 days ,showing toxicity excitement at 10μL of glyphosate ,with the maximal value in 3 day ,39% higher than that in control group .From the day 4 , however , glyphosate showed significant inhibitory effect on P . delicatula and a clear dose-dependent relationship , up to the peak in 80 μL group 7 d after cultivation , the biomass in the experimental group representing 47% of the control group .Glyphosate was found to have stronger toxicity stress on C .saccharophila than on P .delicatula ,being increased with the increase in concentration and time elapse from the 2 d .In 7 day cultivation ,the biomass was found to be 27 .4% of the control group at 10 μL of glyphosate ,24 .6% at 20 μL of glyphosate ,23 .7% at 40 μL of glyphosate ,21 .9% at 60 μL of glyphosate ,and 13% at 80 μL of glyphosate .The glyphosate showed inhibitory effect on chlorophyll a of the algae ,the minimal value in 80 μL group ,and the content of chlorophyll a was only 24 .3% ( P . delicatula) and 7 .54% (C .saccharophila) of the control group .Glyphosate showed much more toxicity stress on C .saccharophila than on P . delicatula ,indicating the feasibility of C .saccharophila as the toxicological evaluation for glyphosate water pollution .%为提示农药污染对水环境破坏，揭示海洋微藻类作为环境毒理学评价指标的潜在应用，研究了塔胞藻、海水小球藻的生长及叶绿素a合成对除草剂草甘膦的致毒胁迫生理应答。试验结果表明，培养前3 d ，在试验质量浓度范围内，草甘膦对塔胞藻生长均无抑制作用，塔胞藻对10μL的草甘膦呈致毒兴奋效应，最高值出现在第3d，比对照组高39％；自第4d开始，草甘膦对塔胞藻呈明显抑制作用，并呈明显的剂量关系，抑制作用在80μL 试验组、培养至7 d时达最高，试验组生物量为对照组的47％；草甘膦对海水小球藻的致毒胁迫作用明显强于对塔胞藻，培养第2 d开始就表现出明显致毒胁迫效应，随草甘膦的质量浓度增加及培养时间的延长，抑制作用增强，增强趋势非常明显，培养至第7 d ，10、20、40、60、80μL试验组生物量分别为对照组的27．4％、24．6％、23．7％、21．9％和13％。草甘膦对塔胞藻、海水小球藻叶绿素a含量均表现抑制效应，最小值出现在80μL试验组，叶绿素a的含量仅为对照组的24．3％和7．54％，对海水小球藻的致毒胁迫效应远大于塔胞藻。表明海水小球藻可作为检测水域环境草甘膦污染的毒理学指标。