庆大霉素对斜生栅藻生长与光合活性的影响

Toxic Effects of Gentamicin on Growth and Activity of Photosynthetic System Ⅱ of Scenedesmus obliquus

抗生素滥用已成为广受关注的环境问题,为考察抗生素对藻类的毒性效应,作者采用叶绿素荧光技术,检测不同浓度庆大霉素处理下培养72 h斜生栅藻的生长及光合活性。结果表明:随着庆大霉素浓度增加,单位细胞的叶绿素a含量减少,光合系统Ⅱ(PSⅡ)活性显著降低,PSⅡ中QA、QB和质体醌之间的电子传递受到阻遏,光合能量分配失衡,这导致藻细胞生长被抑制。另一方面,斜生栅藻通过改变光合能量分配策略来保障逆境下生长代谢所需光能的正常供应,从而缓解庆大霉素胁迫,增强自身耐受能力,确保细胞的存活。由此可见,水环境中日益增加的抗生素含量将显著改变藻类的生长增殖特性,并可能引发其他连锁反应,值得引起重视和关注。

Antibiotics abuse has become one of the major environmental problems being concerned worldwide. In this paper,the toxic effects of antibiotics on algae, Scenedesmus obliquus as a delegate, was investigated by means of measuring chlorophyll a and photosystemⅡ(PSⅡ) photochemical activity, and with gentamicin, a typical antibiotic, being in different concentrations. The investigation showed that gentamicin not only had a notable effect on the content of Chl a, but also inhibited the linear electron transfer between Q;、Q;and plastoquinone, reduced PSⅡphotochemical activity and changed the energy distribution, leading to the growth of Scenedesmus obliquus being markedly inhibited. On the other hand, by changing the PSⅡenergy distribution, the metabolism required by the adversely stressed algae could be met with the photosynthetic energy be normally supplied, thus alleviating the stressed algae, enforcing its tolerance and ensuring the cells survival. It could be seen that increased content of antibiotics in the water environment could significantly change the growth and proliferation characteristics of the algae, and further trigger other chain reactions, therefore, to which sufficient attention should be paid.