长、短期连续孤雌生殖对萼花臂尾轮虫生活史和遗传特征的影响

应用单个体培养、聚丙烯酰胺凝胶垂直板电泳技术和特异性染色方法,以具有明显生化遗传差异的3克隆萼花臂尾轮虫（Brachionus calyciflorus）为对象,对长期（世代数大于200）和短期（世代数约为12）连续孤雌生殖后的轮虫进行了生活史特征和等位酶（PGM,GPI,MDH）分析。结果表明,除3克隆轮虫的生殖后期历时和每个雌体一生中所产的后代数在长期和短期连续孤雌生殖后的个体之间均无显著的差异外（P>0.05）,其它生活史特征在长期和短期连续孤雌生殖后的个体之间的差异均因轮虫克隆的不同而异。克隆对轮虫的胚胎发育时间、幼体阶段历时、生殖期历时、平均寿命、轮虫每个雌体一生中所产的后代数、幼体大小和幼体的耐饥饿时间均有显著的影响（P<0.05）;连续孤雌生殖历期对轮虫幼体阶段历时、平均寿命、后代混交雌体百分率和幼体的耐饥饿时间均有显著的影响（P<0.05）;而克隆和连续孤雌生殖历期间的交互作用对轮虫的胚胎发育时间、生殖期历时、平均寿命、幼体大小和幼体的耐饥饿时间均有显著的影响（P<0.05）。长期连续孤雌生殖后的轮虫幼体阶段历时和幼体的耐饥饿时间均显著短于短期连续孤雌生殖后的轮虫,平均寿命显著长于短期连续孤雌生殖后的轮虫,后代混交雌体百分率显著高于短期连续孤雌生殖后的轮虫。3克隆轮虫在长期和短期连续孤雌生殖后其3种等位酶的酶谱均未出现明显的改变。     

三个品系角突臂尾轮虫生长和发育的比较研究

以浓度为2．4×10^6cells.ml^-1的斜生栅藻为食物,在25℃下,对采自青岛、广州与芜湖等品系的角突臂尾轮虫的胚胎发育、生殖前期和最小世代时间等个体发育阶段历时以及幼体和成体的个体大小、卵体积和相对卵体积进行了研究．结果表明,轮虫的胚胎发育时间、生殖前期历时和最小世代时间等在品系间均存在显著差异．芜湖品系具有最长的胚胎发育时间,其次为广州品系和青岛品系;青岛品系的生殖前期最长,广州品系最短;而最小世代时间以广州品系最小,青岛品系和芜湖品系次之,后两者之间无显著差异．各品系轮虫胚胎发育时间具有随其相对卵体积的增大而缩短的趋势．同一年龄段各品系间的轮虫幼体体积均有显著差异,且均以芜湖品系为最大．三品系轮虫个体幼体体积与其年龄间均呈曲线相关;刚孵化出的幼体体积与其成体间差异在芜湖品系达244．24％,青岛和广州品系分别为182．89％和156．28％．轮虫成体的个体大小、卵大小和相对卵大小在品系间也存在显著差异．     

萼花臂尾轮虫休眠卵大小变异在其生活史对策中的作用

以周期性孤雌繁殖的淡水浮游生物——萼花臂尾轮虫（Brachionus calyciflorus）为研究对象．对其安徽品系的休眠卵进行了大、中、小分组,在2个不同食物浓度条件下培养并观察其种群增长、有性生殖方面的特点,以及后代形态大小和新产休眠卵大小。实验发现休眠卵大小对轮虫种群瞬时增长率、混交雌体百分率和后代形态均没有显著影响;而食物浓度则对轮虫种群的瞬时增长率有显著影响;休眠卵大小和食物浓度均显著影响后代休眠卵的大小。     

温度和食物浓度对三品系萼花臂尾轮虫实验种群动态的影响

应用个体培养方法,研究了温度(20、2和30 ℃)和藻类食物浓度(1.5×10₆、3.0×10₆、6.0×10₆和9.0×10₆ cells·ml^-1)对青岛、芜湖、广州三品系萼花臂尾轮虫种群动态的影响.结果表明,温度仅对轮虫的世代时间和种群内禀增长率有显著影响,而品系对所有生命表参数均无显著影响.轮虫种群的内禀增长率随培养温度的升高而增大,世代时间则随培养温度的升高而缩短.食物浓度仅对轮虫的生命期望值和平均寿命有显著影响,品系对轮虫的净生殖率、世代时间、生命期望值和平均寿命也有显著影响.三品系间,以广州品系轮虫的净生殖率、世代时间、生命期望值和平均寿命最大,芜湖品系最短.当食物浓度为3.0×10₆ cells·ml^-1时,轮虫的生命期望值和平均寿命最长,9.0×10₆ cells·ml^-1时最短.各品系轮虫的净生殖率、世代时间、总生殖率、生命期望值和平均寿命均随培养温度的升高而减小,广州品系的净生殖率除外.轮虫种群的内禀增长率和广州品系轮虫的总生殖率则随培养温度的升高而增大.青岛和广州品系轮虫的各生命表参数,均与食物浓度呈曲线相关,但芜湖品系仅世代时间、平均寿命和生命期望值随食物浓度的增大而缩短.     

温度和食物浓度对三品系萼花臂尾轮虫实验种群动态的影响

应用个体培养方法,研究了温度(20、25和30℃)和藻类食物浓度(1．5×10^6、3．0×10^6、6．0×10^6和9．0×10^6cells·ml^-1)对青岛、芜湖、广州三品系萼花臂尾轮虫种群动态的影响．结果表明,温度仅对轮虫的世代时间和种群内禀增长率有显著影响,而品系对所有生命表参数均无显著影响．轮虫种群的内禀增长率随培养温度的升高而增大,世代时间则随培养温度的升高而缩短．食物浓度仅对轮虫的生命期望值和平均寿命有显著影响,品系对轮虫的净生殖率、世代时间、生命期望值和平均寿命也有显著影响．三品系间,以广州品系轮虫的净生殖率、世代时间、生命期望值和平均寿命最大,芜湖品系最短．当食物浓度为3．0×10^6cells·ml^-1时,轮虫的生命期望值和平均寿命最长,9．0×10^6cells·ml^-1时最短．各品系轮虫的净生殖率、世代时间、总生殖率、生命期望值和平均寿命均随培养温度的升高而减小,广州品系的净生殖率除外．轮虫种群的内禀增长率和广州品系轮虫的总生殖率则随培养温度的升高而增大．青岛和广州品系轮虫的各生命表参数,均与食物浓度呈曲线相关,但芜湖品系仅世代时间、平均寿命和生命期望值随食物浓度的增大而缩短．     

孤雌生殖累积世代数和雌体年龄对萼花臂尾轮虫繁殖的影响

采用单个体培养方法,研究了孤雌生殖的累积世代数和雌体年龄对萼花臂尾轮虫混交雌体形成和产卵量的影响,结果表明,随着轮虫孤雌生殖累积世代数和增加,各代中的总混交雌体百分率呈减小的趋势,年轮的雌体可产生较多的混交雌体,非混交雌体所产后代中的总混交雌体百分率具有随其祖母年龄的增大而增大的趋势,孤雌生殖的累积世代数对轮对轮虫非混交雌体的平均产卵量无显著的影响,非混交雌体的年龄对其报代的平均产卵量亦无显著的影响。     

三个地理品系萼花臂尾轮虫生活史特征的比较

应用单个体培养方法 ,以浓度为 4 0× 10 6 cells ml的斜生栅藻 (Scenedesmusobliquus)为食物 ,在 30℃下 ,对采自广州、芜湖和青岛等地的萼花臂尾轮虫的生活史特征进行了比较研究。结果发现 ,三个地理品系的萼花臂尾轮虫除生殖前期历时无显著差异外 ,其生殖期历时、生殖后期历时、平均寿命和产卵量等均存在显著的差异。轮虫种群的内禀增长率、周限增长率和净生殖率均以芜湖品系最大 ,广州品系最小。这表明若要在 30℃下进行萼花臂尾轮虫的规模化生产 ,芜湖品系应是首选的最适品系     

萼花臂尾轮虫种复合体内三个姐妹种生活史特征的比较研究

应用生命表统计学方法,在13℃、18℃、23℃和28℃下对采自芜湖市莲塘湖和荷花塘水体中的萼花臂尾轮虫三个姐妹种HE1、HE3和LE9的生活史特征进行了比较研究。结果表明,三个姐妹种生命表参数间的差异因温度的不同而异。13℃下,姐妹种LE9的生命期望、平均寿命和世代时间都显著长于姐妹种HE3,LE9的净生殖率和种群内禀增长率均最大,三个姐妹种所产后代中的混交雌体百分率无显著的差异。18℃下,姐妹种LE9的生命期望和平均寿命显著长于姐妹种HE3,姐妹种LE9的世代时间显著长于姐妹种HE1和HE3,姐妹种 HE3的种群内禀增长率显著高于姐妹种LE9,姐妹种HE3所产后代中的混交雌体百分率最高,三个姐妹种的净生殖率无显著的差异。23℃下,姐妹种HE1的生命期望、平均寿命和世代时间均最长,姐妹种HE1所产后代中的混交雌体百分率显著低于HE3,三个姐妹种的净生殖率和种群内禀增长率均无显著的差异。28℃下,三个姐妹种的生命期望、平均寿命、世代时间和种群内禀增长率均无显著的差异;姐妹种HE1的净生殖率最低;姐妹种HE3所产后代中的混交雌体百分率最高。三个姐妹种的生命表参数对升高的温度的响应也不相同。温度、姐妹种及两者间的交互作用对轮虫的世代时间、平均寿命、出生时的生命期望和轮虫所产后代中的混交雌体百分率均有显著的影响;温度和姐妹种对轮虫的净生殖率和种群内禀增长率均有极显著影响,但两者的交互作用对其无显著性影响。     

氯氰菊酯和溴氰菊酯对萼花臂尾轮虫生殖的影响

以萼花臂尾轮虫(Brachionus calyciflorus)为受试动物,运用3d种群增长和4d休眠卵产量实验方法研究了不同浓度的氯氰菊酯(31.25、62.5、125、250、500、1000 μg/L和2000 μg/L)和溴氰菊酯(15.63、31.25、62.5、125、250μg/L和500 μg/L)对轮虫生殖的影响.结果显示,氯氰菊酯浓度对轮虫种群增长率、轮虫种群中的OF/NOF值和MF/AF值、混交率和休眠卵产量均有显著影响(P均＜0.001),但对轮虫混交雌体受精率无显著的影响(P＞0.05);溴氰菊酯浓度对轮虫种群增长率、轮虫种群中的MF/AF值、混交率和休眠卵产量均有显著影响(P均＜0.05),但对轮虫种群中的OF/NOF值和混交雌体受精率均无显著的影响(P＞0.05).与空白对照组相比,31.25-125 μg/L的氯氰菊酯和除31.25 μg/L外所有浓度的溴氰菊酯都显著升高了轮虫的种群增长率,而1000 μg/L和2000 μg/L的氯氰菊酯却显著降低了轮虫的种群增长率;500 μg/L的氯氰菊酯使轮虫种群中的带卵雌体数/不带卵雌体数显著升高,而各浓度的溴氰菊酯对其无显著影响;62.5 μg/L和125 μg/L的氯氰菊酯显著升高了轮虫种群中的混交雌体数/非混交雌体数,而15.63 μg/L的溴氰菊酯却显著降低了轮虫种群中的混交雌体数/非混交雌体数;62.5-250 μg/L的氯氰菊酯显著升高了轮虫混交率,而500-2000 μg/L的氯氰菊酯以及15.63、31.25、250 μg/L和500μg/L的溴氰菊酯却均显著降低了轮虫混交率;62.5 μg/L和125 μg/L的氯氰菊酯以及15.63 μg/L和125 μg/L的溴氰菊酯均显著升高了轮虫的休眠卵产量.包括空白对照组在内,所有测试液内的轮虫混交雌体受精率均为零.在实验设置的浓度范围内,氯氰菊酯浓度与轮虫的种群增长率、轮虫种群中的混交雌体数/非混交雌体数及轮虫混交率间均具有显著的剂量-效应关系.     

萼花臂尾轮虫(Brachionus calyciflorus)种复合体内三个姐妹种生活史特征比较

采自芜湖市莲塘湖和荷花塘水体中的萼花臂尾轮虫3个姐妹种HE1、HE3和LE9在13℃、18℃、23℃和28℃下的生命表参数间的差异表现为13℃和18℃下姐妹种LE9的生命期望和平均寿命都显著长于姐妹种HE3,23℃下姐妹种HE1的生命期望和平均寿命均最短;13℃下姐妹种LE9的世代时间显著长于姐妹种HE3,18℃下和23℃姐妹种LE9和HE1的世代时间分别最长和最短;13℃下姐妹种LE9的净生殖率最高,28℃下姐妹种HE1的净生殖率最低;13℃下姐妹种LE9的种群内禀增长率最高,18℃下姐妹种HE3的种群内禀增长率显著高于姐妹种LE9;18℃和28℃下姐妹种HE3所产后代中的混交雌体百分率最高,23℃下姐妹种HE1所产后代中的混交雌体百分率显著低于HE3.3个姐妹种的生命表参数对升高的温度的响应也不相同.温度、姐妹种及两者间的交互作用对轮虫的世代时间、平均寿命、出生时的生命期望和轮虫所产后代中的混交雌体百分率均有显著的影响;温度和姐妹种对轮虫的净生殖率和种群内禀增长率均有极显著影响,但两者的交互作用对其无显著性影响.     

萼花臂尾轮虫有性生殖、种群增长和休眠卵产量间的关系

利用种群指数增长和Logistic增长模型,通过计算机模拟研究了萼花臂尾轮虫有性生殖发生的频率,后代中的混交雌体发率对种群增长和休眠卵产量的影响。在所模拟的参数范围内,随有性生殖发生频率由100％减小到20％,获得了大休眠卵产量所需的混交雌体百分率由9％增大到69％,随密度制约作用的增大（环境容纳量K值由1000减小到100）,该混交雌体百分率由18％增大到69％,休眠卵产量由1072．10降低至133．67,种群的内禀增长率与获得最大休眠卵产量所需的混交雌体百分率间呈曲线相关。当有性生殖发生得越频繁,种群增长所受的密度制约作用较小时,后代中10％－30％的个体为混交雌体时的种群中休眠卵产量较大。     

种群起始密度对萼花臂尾轮虫休眠卵形成的影响

应用群体累积培养法,研究了种群起始密度对萼花臂尾轮虫休眠卵的形成及之相关的混交雌体百分率和受精率的影响,结果表明,在连续１１ｄ的培养中,轮虫休眠卵的产量和形成效率以及种群中的平均混交雌体百分率以种群起始密度为１．０－１０．０ｉｎｄ．ｍｌ＾－１组最大,２０．０ｉｎｄ．ｍｌ＾－１组次之,５０．０ｉｎｄ．ｍｌ＾－１组最小,各组间的平均混交雌体受精率则无显著差异,对轮虫休卢卵最大形成效率及其出现的时间以及     

An individual-based population model for the prediction of rotifer population dynamics and resting egg production

Most species of rotifers have a combination of sexual and asexual reproduction, with sexual reproduction resulting in resting eggs, which can lay dormant for long periods. The occurrence of sexual reproduction affects population dynamics through the temporary presence of male rotifers, and a reduction in the growth of the number of female rotifers. A previously published, individual-based model used dynamic energy budget theory to describe rotifer food intake, growth, egg production, and mortality, but assumed asexual reproduction only. In the current study, we have expanded the model to describe the entire reproductive cycle of the rotifers, making it usable for investigating relationships, such as those between the signal triggering mictic egg production, and the timing and number of resting eggs produced. The model is intended for use in predicting the specific future development of cultures, for instance, as a process model in rotifer or resting egg production for aquaculture. Guest editors: S. S. S. Sarma, R. D. Gulati, R. L. Wallace, S. Nandini, H. J. Dumont & R. Rico-Martínez Advances in Rotifer Research     

A model evaluating the contribution of environmental factors to the production of resting eggs in the rotifer Brachionus plicatilis

The production of resting eggs by the rotifer Brachionus plicatilis was tested at four salinities (9, 18, 27 and 36\%) and six concentrations of the alga Chlorella stigmatophora (0.25, 0.5, 1.0, 2.0, 4.0 and 6.0 × 10⁶ cells ml^–1). The results indicated that resting eggs were produced only at two salinities (9\% and 18\%) and that their number was affected by the amount of food provided. A model consisting of two generalized linear sub-models was built to evaluate the contribution of each of the tested food concentrations at the two salinities. The sub-models were used to distinguish between two different components of resting egg production: one related to the presence or absence of resting egg production, and the other to the number of resting eggs produced, given that production had occurred. Besides indicating the best combination of salinity and food concentration for obtaining large numbers of resting eggs, they revealed the contribution of internal population factors that were not controlled in the course of the experiment. The model identified the positive contribution of the relative number of females to males, and the negative association between high rotifer densities and the production of resting eggs. The results of the present study help in defining the optimal conditions for mass production of resting eggs, which are of potential importance in aquaculture.Deceased, September 1991.     

Chromosomes and isozymes of hypotriploid strains of the rotifer Brachionus plicatilis

Some S type strains of the rotifer Brachionus plicatilis were found to have particular band patterns of certain enzymes, which suggested that the strains were triploids or trisomics for some chromosomes. Chromosomes of the strains were then observed by a conventional squash method of preparation. Analysis of chromosomes was made in comparison with the karyotype of amictic female S type rotifer. The strains were found to be hypotriploids. A strain which was derived from one of the hypotriploid strains was also studied, and was found to be diploid. The relationship between the chromosomes, the isozyme patterns, the origin of the hypotriploid strain and the derived diploid strain were discussed.     

Effect of incubation and preservation on resting egg hatching and mixis in the derived clones of the rotifer Brachionus plicatilis

The marine rotifer Brachionus plicatilis typicus (Clone 8105A, Univ. of Tokyo) was cultured in 500 ml beakers to form resting eggs. Tetraselmis tetrathele was used as a culture food. Just after formation, resting eggs were exposed to various temperature (5–25 °C) and light regimes (24L: OD and OL : 24D). When eggs were exposed to light just after formation, the eggs hatched sporadically over a month. No hatching was observed for six months when eggs were preserved under dark conditions regardless of the temperature. These eggs hatched simultaneously after being exposed to light and eggs preserved at 5 °C showed twice as high hatching rate (40%) as that of eggs preserved at 15–25 °C (24%). Clones from resting eggs that were kept under different temperature and light regimes were reared individually to the third generation. Incubation at 25 °C with lighting produced the highest (5.4% and 5.2 %) rate of mictic females during their 2nd and 3rd generations, respectively. The lowest rates (0 and 1.5%) were found when the eggs were kept at 5 °C in total darkness for six months. A lower rate of amictic female production was found in clones with higher rates of mixis.     

淡水轮虫休眠卵的研究进展

本文综述了温度、休眠卵形态、光照条件和休眠卵贮存条件等因子对轮虫休眠卵萌发的影响, 以及休眠卵萌发型式差异的生态学意义。温度骤变可以诱导休眠卵萌发, 光照条件对休眠卵萌发率的影响存在种间差异, 母体轮虫的食物和休眠卵贮存条件影响其萌发率。     

枝角类休眠卵形成和萌发的研究进展

综述了多年来国内外对枝角类休眠卵的研究概况,重点介绍了休眠卵的形态、形成的条件、保存方式及萌发条件等.休眠卵通常呈圆形或椭圆形,外被一层厚的卵膜.休眠卵的形成主要依赖于生物因子(遗传因素、种群密度等)和非生物因子(温度、食物、光照等)的作用.影响休眠卵萌发的因子有休眠卵的保存方式、保存时间、萌发阶段的光照及温度等.     

Sex, parthenogenesis and genetic structure of rotifers: microsatellite analysis of contemporary and resting egg bank populations

Cyclically parthenogenetic rotifers are a valuable model for investigating the relationship between reproductive mode and population structure, although advances in this field have been hindered by low allozyme variability in these organisms. A high genotypic diversity is predicted after population establishment, which would be eroded by clonal selection during the parthenogenetic phase. The resting egg bank, produced sexually, is presumed to store high levels of genetic diversity, with subsequent effects on planktonic population structure. Here, we provide the first application of microsatellite markers to a rotifer planktonic population and its associated resting egg bank. Seven polymorphic microsatellite loci were screened in populations of the rotifer Brachionus plicatilis in a temporary pond to analyse: (i) the genetic structure of the resting egg bank; (ii) the changes in the genetic structure of rotifer populations during the parthenogenetic phase; and (iii) the population structure after its initiation from resting eggs. Microsatellites proved to be a useful tool for clone identification, revealing a surprisingly high clonal diversity in rotifer populations. The last sample in the parthenogenetic phase showed evidence of clonal selection, as indicated by a low observed clonal diversity and the appearance of linkage disequilibria. The resting egg bank, analysed comprehensively for the first time in any zooplankter, is in Hardy-Weinberg and linkage equilibrium, and contains a high genotypic diversity. Unexpectedly, the resting egg bank differed from the planktonic population in its allelic composition, suggesting that resting egg hatching is biased.     

White spot syndrome virus (WSSV) detected by PCR in rotifers and rotifer resting eggs from shrimp pond sediments

White spot syndrome virus (WSSV) was detected by PCR-dot blot hybridization in rotifer resting eggs from shrimp Penaeus chinensis culture-pond sediments. It was also detected in rotifers hatched from those eggs. Surface disinfection before analysis indicated that WSSV was probably present within the resting eggs. Results suggested that rotifer resting eggs may be an overwintering reservoir for WSSV in shrimp ponds.