盐酸四环素浓度和食物密度对萼花臂尾轮虫生活史特征的综合影响

近年来,抗生素的环境污染问题已引起人们的广泛关注,其在环境中的残留可对水生态系统的结构和功能产生重要影响。迄今,盐酸四环素浓度和食物密度对轮虫生活史特征的影响研究尚未见报道。以萼花臂尾轮虫(Brachionus calyciflorus)为受试动物,研究了在不同斜生栅藻(Scenedesmus obliquus)密度下,不同浓度的盐酸四环素(Tetracycline hydrochloride)对萼花臂尾轮虫生活史特征的影响。结果表明,食物密度和盐酸四环素浓度对轮虫的生命期望、净生殖率、世代时间、内禀增长率、平均寿命和后代混交率,以及食物密度和盐酸四环素浓度间交互作用对除了内禀增长率外的其他5个统计学参数均具有显著影响。在各食物密度下,轮虫的特定年龄繁殖率高峰值随着盐酸四环素浓度的增加呈现先增加后降低的趋势;盐酸四环素对轮虫生长和繁殖参数的影响呈现"低促高抑"的特点。3个食物密度下,高浓度的盐酸四环素显著提高了萼花臂尾轮虫的后代混交率,且在1.0×10~6个/mL藻密度下毒物浓度与轮虫后代混交率间具有显著的剂量-效应关系。食物密度的高低显著影响盐酸四环素对萼花臂尾轮虫的毒性效应。

Comprehensive effects of tetracycline hydrochloride concentration on life history traits of Brachionus calyciflorus under different food densities

Increasing attention has been paid to the challenging issue of environmental pollution by antibiotics in recent years, and the structure and functioning of aquatic ecosystems could be disturbed by residues remaining in the environment. To date, however, few attempts have been made to investigate the effects of tetracycline hydrochloride on life history traits of rotifers under different food densities. In this study, the effects of tetracycline hydrochloride concentration on life table demography of Brachionus calyciflorus under different Scenedesmus obliquus densities were studied. The results showed that tetracycline hydrochloride concentration and food density had significant effects on life expectancy at hatching, net reproductive rate, generation time, intrinsic rate of population increase, average lifespan, and proportion of sexual offspring of B. calyciflorus. In addition, the interaction of tetracycline hydrochloride concentration and food density had a marked influence on five demographic parameters, except for the intrinsic rate of population increase, in rotifers. The peak of age-specific fecundity in B. calyciflorus increased to a maximum and then decreased with increasing concentration of tetracycline hydrochloride under each food density. The effects of tetracycline hydrochloride on the growth and reproduction of B. calyciflorus presented a pattern of hormesis. Mixis rate of offspring in rotifers increased at the high concentration of tetracycline hydrochloride under the three food densities, and there were significant dose-effect relationships between tetracycline hydrochloride concentration and the proportion of sexual offspring at the 1.0×10⁶ cells/mL food density. Levels of food density played an important role in the poisoning effects of tetracycline hydrochloride on B. calyciflorus.