3种抗生素对黑麦草种子萌发的生态毒性效应

为探明四环素、环丙沙星和磺胺嘧啶3种抗生素对黑麦草种子萌发的影响,为评价抗生素污染的生态影响提供科学依据,采用保湿培养法研究了它们对黑麦草种子萌发的影响,比较分析了抗生素的生态毒性差异和相对敏感的指标。结果表明,在种子萌发期,一定浓度范围的抗生素胁迫会引发植物种子抵抗逆境的应激反应,因此,3种抗生素在1 mg·L~(-1)处理水平下均能促进种子发芽。超过该浓度,四环素对黑麦草种子发芽仍有一定的促进作用,而环丙沙星和磺胺嘧啶则表现为抑制作用。四环素对种子发芽率的最大无作用浓度(NOEC)为5 mg·L~(-1),而环丙沙星和磺胺嘧啶对种子发芽率的NOEC为1 mg·L~(-1)。实验结束时,3种抗生素在1 mg·L~(-1)处理水平下的种子发芽率最高。3种抗生素浓度超过0.1 mg·L~(-1)时,种子根长和芽长即受到抑制,因此,它们对种子根长和芽长的NOEC均为0～0.1 mg·L~(-1)。其中,磺胺嘧啶的抑制作用最为显著。根长受到抑制的程度强于芽长。黑麦草种子萌发受3种抗生素影响程度依次为磺胺嘧啶环丙沙星四环素。

Ecotoxicological Effects of Three Antibiotics on Seed Germination of Lolium perenne

The effects of three antibiotics, i.e., tetracycline, ciprofloxacin and sulfadiazine, on Lolium perenne seed germination was studied by adopting a moisture retention culture method, and the differences of ecological effects and relative sensitive indicators of antibiotics were compared and analyzed. The results showed that three antibiotics could promote seed germination rate at the concentration of 1 mg L^-1 during the germination process, because antibiotic would induce stress responses of plant seeds in certain concentration. When the concentration of antibiotics were greater than 1 mg L^-1, tetracycline could promote the seed germination rate of Lolium perenne to some extent, while ciprofloxacin and sulfadiazine could inhibit it. The no observed effect concentration (NOEC) of tetracycline on seed germination rate was 5 mg L^-1, while that of ciprofloxacin and sulfadiazine on seed germination rate was 1 mg L^-1. The germination rate in the three antibiotics treatments were highest at 1 mg L^-1 group at the end of the experiment. The root and bud length of the seeds were significantly inhibited under three antibiotics stress when the concentration was higher than 0.1 mg L^-1, and therefore the NOEC of three antibiotics on root and bud length were both between 0 and 0.1 mg L^-1. The inhibition effect of sulfadiazine was the most significant, and the inhibition degree of root length was higher than that of bud length. The effects of three antibiotics on Lolium perenne seed germination followed the order: sulfadiazine > ciprofloxacin > tetracycline. The experimental results provide scientific basis for evaluating ecological effects of antibiotics pollution.