【作者】 李蕾； 王岩； 陈桃英；

【Author】 LI Lei WANG Yan CHEN Tao-ying (Laboratory of Aquatic Ecology and Fish Nutrition,Shanghai Fisheries University,Shanghai 200090,China)

【机构】 上海水产大学水域生态与鱼类营养实验室；

【摘要】 实验室内研究了光照周期和种群密度对蒙古裸腹溞（Moina mongolica）生殖转换的影响。溞种群密度设为0.1、0.5、1.0 ind/ml,光照周期设为L:D=0:24、3:21、6:18、9:15、12:12。实验期间以海水小球藻（Chlorella spp）为蒙古裸腹溞的食物,小球藻浓度为6×10⁶ ind/ml.d。温度控制为25℃。当种群密度为0.1 ind/ml时,所有的光照处理均没有雄体和休眠卵产生;种群密度为0.5 ind.ml^-1和1 ind/ml时都有雄体和休眠卵产生,但1 ind.ml^-1组雄体和休眠卵产生比例相对较高。在相同密度条件下,L:D=12:12时开始出现雄体和休眠卵;L:D=9:15、L:D=6:18和L:D=3:21条件下有大量雄体和休眠卵的产生,其中L:D=6:18时休眠卵产生的数量明显高于其它组:在L:D=0:24条件下有少量雄体产生,但未发现休眠卵。本实验表明,短光期和种群密度的协同作用可诱导蒙古裸腹溞从孤雌生殖转向有性生殖。在相同的光照周期下,种群密度的高低与对蒙古裸腹溞生殖转换诱导作用的强弱呈正相关,0.1 ind/ml密度不能诱导蒙古裸腹溞发生生殖转换;在相同的种群密度下,L:D=12:12是诱导蒙古裸腹溞发生生殖转换的临界光周期,L:D=6:18是诱导蒙古裸腹溞发生生殖转换的最有效光周期。更多还原

【Abstract】 This paper examined the effect of photoperiod and crowding on the switch of Moina mongolica from parthenogenetic to sexual reproduction.Three population density,0.1、0.5、1.0 ind.ml^-1and five photoperiod,L:D=0:24、3:21、6:18、9:15、12:12,were established.During the experiment,M.raongolica was fed Chlorella spp at 6×10⁶ind/mL.d.Temperature was controlled at 25℃and salinity at 10.There was no production of either male or resting egg in the density treatment of 0.1 ind/mL.In the density treatment of 0.5 and 1 ind/ml,production of male and resting egg was observed,and more males and resting eggs was induced in the treatment of 1 ind.ml^-1than the treatment of 0.5 ind/ml.There was production of male and resting egg under the photoperiod of L:D=12:12,and a great amount of male and resting egg were induced under L:D=9:12,L:D=6:18 and L:D=3:21.Under L:D=6:18 the most male and resting egg occurred,while L:D=0:24 induced few male without resting eggs.The present study showed short light period and high population density were responsible in the reduction of male and resting egg for M.mongolica.There was a positive correlation between density and production of male or resting egg,and the density of 0.1 ind.ml^-1could not induce male and resting egg.L:D=12:12 was the photoperiod critical for inducing sexual reproduction of M.mongolica,and L:D=6:18 was the photoperiod most efficient to switch the reproduction M.mongolica from parthenogenetic to sexual reproduction.更多还原