CAJ | 학술논문

以铜绿微囊藻(Microsystis aeruginosa)作为生物模型,通过测定藻细胞氧化损伤程度与藻细胞内外藻毒素LR(microcystin-LR,MC-LR)的含量,研究除草剂禾草灵的生态毒性.结果表明,禾草灵在实验室处理质量浓度1,2,5 mg/L 下,能诱导铜绿微囊藻细胞活性氧(reactive oxygen species,ROS)的产生,引起细胞脂质过氧化水平丙二醛(malondialdehyde,MDA)的提高和超氧化物歧化酶(superoxide dismutase,SOD)的活性增强.说明禾草灵对铜绿微囊藻产生了氧化胁迫.5 mg/L 禾草灵使铜绿微囊藻释放到细胞外的微囊藻毒素 MC-LR 显著增加,为空白对照的68.5,2.11,2.50,123.67倍(第2,3,4,5天)；细胞内 MC-LR 含量与空白对照相比有一定的降低,为空白对照的0.34,0.82,2.76,0.11倍(第2,3,4,5天).说明禾草灵在一定质量浓度下能对铜绿微囊藻产生氧化胁迫,引起藻细胞脂质过氧化,从而引起细胞膜损伤,导致微囊藻毒素 MC-LR 更多的释放到水体中,对水环境造成一定的影响.实验结果可对禾草灵的环境安全评价提供一定的参考.
이동록미낭조(Microsystis aeruginosa)작위생물모형,통과측정조세포양화손상정도여조세포내외조독소LR(microcystin-LR,MC-LR)적함량,연구제초제화초령적생태독성.결과표명,화초령재실험실처리질량농도1,2,5 mg/L 하,능유도동록미낭조세포활성양(reactive oxygen species,ROS)적산생,인기세포지질과양화수평병이철(malondialdehyde,MDA)적제고화초양화물기화매(superoxide dismutase,SOD)적활성증강.설명화초령대동록미낭조산생료양화협박.5 mg/L 화초령사동록미낭조석방도세포외적미낭조독소 MC-LR 현저증가,위공백대조적68.5,2.11,2.50,123.67배(제2,3,4,5천)；세포내 MC-LR 함량여공백대조상비유일정적강저,위공백대조적0.34,0.82,2.76,0.11배(제2,3,4,5천).설명화초령재일정질량농도하능대동록미낭조산생양화협박,인기조세포지질과양화,종이인기세포막손상,도치미낭조독소 MC-LR 경다적석방도수체중,대수배경조성일정적영향.실험결과가대화초령적배경안전평개제공일정적삼고.
Summary Diclofop-methyl is a postemergence herbicide introduced in the 1 960s.It is widely used on wheat, barley,and golf courses (turf) all over the world.Residues of diclofop-methyl may pollute the water system and affect the physiological processes in cyanobacteria.Causative cyanobacteria can often cause serious environmental, aesthetic,and economic problems;besides,it can produce microcystins(MCs)which are toxic to domestic livestock and wildlife.Certain environmental factors such as pH,temperature,and the amount of nitrogen and phosphorus in the water have been found to affect the production of MCs.But other factors,such as the concentration of environmental pollutants including pesticide residues which may be prevalent in aquatic ecosystems,have not been studied in sufficient detail. <br> In the current study,oxidative damage and toxin release from Microsystis aeruginosa caused by diclofop-methyl were investigated.Diclofop-methyl was proposed to induce oxidative stress in susceptible plant tissues and to collapse the transmembrane proton gradient.Cells can develop a set of cellular defense systems via enzymatic and non-enzymatic antioxidants to counteract the toxicity of reactive oxygen species (ROS) like H 2 O 2 ,O 2? and ?HO. In the enzymatic pathways,superoxide dismutase(SOD) is important to scavenge ROS. <br> The results showed that diclofop-methyl induced the generation of ROS,increased the concentration of malondialdehyde(MDA),enhanced the activity of SOD and triggered toxin release in M.aeruginosa to varying degrees.After 4 h of treatment,diclofop-methyl induced ROS generation by 3%,4% and 4% under 1,2 and 5 mg/L,respectively.After 8 d of treatment,1 mg/L and 5 mg/L diclofop-methyl induced ROS generation by 12%and 43%,respectively.After 9 d treatment,5 mg/L diclofop-methyl induced ROS generation by 1 1%.The concentrations of MDA were 3.47,1.86 and 10.61 folds compared to the control after 24 h treatment of 1,2 and 5 mg/L diclofop-methyl.After 48 h treatment,the MDA concentrations were 4.89,1.48,and 0.1 7 folds compared to the control for 1,2 and 5 mg/L diclofop-methyl,respectively.The activities of SOD were 1.64,1.25 and 2.26 folds compared to the control after 24 h treatment of 1,2 and 5 mg/L diclofop-methyl,and after 48 h treatment, the folds were 2.36,4.02 and 2.52 for 1,2 and 5 mg/L diclofop-methyl,respectively. <br> At the concentration of 5 mg/L diclofop-methyl the extracellular MC-LR contents in M.aeruginosa were 68.5,2.1 1,2.50 and 123.67 folds compared to the control from the second day to the fifth day,respectively. However,the intracellular MC-LR contents in 5 mg/mL diclofop-methyl treated samples were lower than the control,which were 0.34,0.82,2.76 and 0.1 1 folds from the second day to the fifth day,respectively. <br> In conclusion,diclofop-methyl may collapse the transmembrane proton gradient and destroy the cell membrane through lipid peroxidation and free radical oxidation,which results in more MC-LR release from cyanobacteria to the water body.The results are helpful in understanding the effects of diclofop-methyl on cyanobacteria,which is important for environmental assessment and protection.It is also helpful for guiding the application of diclofop-methyl in agricultural settings.