食物浓度和品系对萼花臂尾轮虫生殖期历时和混交雌体形成的影响

Effects of food concentration on the duration of reproductive period and the formation of mictic female in different strains of freshwater rotifer Brachionus calyciflorus

应用单个体培养方法比较研究了藻类食物浓度(2.0、5.0、8.0和11.0×106cells/mL)和品系对采自广州、青岛和芜湖等地的萼花臂尾轮虫生殖期历时、后代数和后代中混交雌体百分率的影响。结果表明,食物浓度对轮虫的生殖期历时和轮虫全部后代中的混交雌体百分率有显著的影响,但对轮虫的总后代数无显著的影响。品系对轮虫的生殖期历时、总后代数和全部后代中的混交雌体百分率均有显著影响。3品系间,广州品系轮虫的生殖期历时最长,为(4.53±0.19)d;总后代数最多达(18.75±0.26)个;全部后代中的混交雌体百分率最低,仅为4.32%±0.51%。而青岛品系轮虫全部后代中的混交雌体百分率最高,达49.90%±2.15%;其生殖期历时和总后代数与芜湖品系间均无显著的差异。食物浓度和品系间的交互作用仅对轮虫全部后代中的混交雌体百分率有显著影响。3品系中,仅芜湖品系轮虫的生殖期历时、总后代数和全部后代中的混交雌体百分率受食物浓度的显著影响;母体年龄对轮虫每天所产后代中的混交雌体百分率的影响因轮虫品系的不同和培养时所用的食物浓度的不同而异。

Strain is one of the most important internal factors which determine the micitc female formation and resting egg production in rotifers. Studies on the differences of mictic female formation among different rotifer strains not only can accumulate material for demonstrating the role of genetic factors in determining micitc female formation but also are important for selecting suitable rotifer strains for the mass production of resting eggs. In this study, the effect of food concentration （2.0, 5.0, 8.0 and 11.0 × 10^6 cells/mL）of algae Scenedesmus obliquus on the duration of reproductive period, the number of offspring and the percentage of mictic females in the offspring of three Brachionus calyciflorus strains collected from Guangzhou, Wuhu and Qingdao of China respectively was studied with replicated individual cultures at （25±1）C. The results showed that the effect of food concentration on the duration of reproductive period and the percentage of mictic females in all the offspring were significant, but there was no effect on the number of total offspring. Among the four food concentrations, the reproductive period of the rotifer cultured at 8.0 × 10^6cells/mL of Scenedesmus was the longest （4.19 days）, whereas the differences in the other three food concentrations were not significant. The percentage of mictic females in all the offspring produced by the rotifer in her lifetime at the food concentration of 5.0 × 10^6cells/mL was the highest （43.35%）, and that at 11.0 × 10^6cells/mL was the lowest （16.87%）. Strain influenced significantly the duration of reproductive period, the number of total offspring and the percentage of mictic females in all the offspring. Among the three strains, Guangzhou strain had the longest reproductive period （4. 53 days）, produced the largest number of offspring （18. 75 individuals） in her lifetime, and had the lowest percentage of mictic females （4. 32%） in all the offspring. Oingdao strain had the highest percentage of mictic female （49.90%） in all the offspring, but its duration of reproductive period and number of offspring produced in her lifetime were both similar to those of Wuhu strain. The interaction between food concentration and strain influenced markedly only on the percentage of mictic females in all the offspring. Among the three strains, the duration of reproductive period, the number of total offspring and the percentage of mictic females in all the offspring were significantly influenced by food concentration only for Wuhu strain. The effect of the age of rotifer mother on the percentage of mictic females in the offspring produced daily by her differed with both rotifer strain and food concentration, and only the percentage of mictic females in the offspring produced daily by Wuhu and Qingdao strains at both 5.0 × 10^6 and 8.0 × 10^6cells/mL of food concentrations lowered significantly with their ages.