两品系萼花臂尾轮虫的生活史特征和受精率研究

应用单个体培养和群体培养方法,在25℃条件下,对萼花臂尾轮虫Brachionus calyciflorus南京品系(NJ)和美国佛罗里达品系(FL)的幼体发育时间、胚胎发育时间、繁殖量、种群增长参数及品系间、品系内受精率进行了研究.结果表明:萼花臂尾轮虫FL品系与NJ品系的幼体发育时间、第一个幼体孵出时间和繁殖量之间均无显著性差异(P＞0.05),而NJ品系的胚胎发育时间比FL品系显著缩短6.9％(P＜0.05); NJ品系的净生殖率(R0)、内禀增长率(rm)、世代时间(T)和生命期望(e0)均显著大于FL品系(P＜0.05)；萼花臂尾轮虫FL和NJ品系雌雄交配试验结果表明,两品系间的受精率低于各自品系内交配的受精率.本研究表明,南京品系和佛罗里达品系萼花臂尾轮虫的发育和种群增长参数存在显著差异,但两品系之间不存在完全的生殖隔离,未形成姐妹种.

The life cycle characteristics and fertilization rate in two strains of rotifer Brachionus calyciflorus

Many zooplankton species including rotifer previously considered as cosmopolitan are complexes of sibling species.In the present study,durations of juvenile period,durations of embryonic development,lifetime fecundity,life cycle parameters and fertilization rate were studied in Nanjing（NJ） strain collected from Nanjing,China and Florida（FL） strain of Brachionus calyciflorus.There were no significant differences in the juvenile period,hatching time of the first neonate and lifetime fecundity in FL and NJ strains（P0.05）.The NJ strain had significantly shorter durations of embryonic development than FL strain（P0.05）,being induced by 6.9%.The net reproduction rate（R0）,life expectancy（e0）,the intrinsic rate of population increase（rm） and the generation period（T） were found to be higher in NJ strain than in FL strain（P0.05）.Cross-mating tests demonstrated that the fertilization rate was less between NJ strain and FL strain than that in the strains,demonstrating that completely reproductive isolation was not found in the two strains,and that the NJ and FL strains were not sibling species in B.calyciflorus species complex.