镜湖不同湖区沉积物中轮虫休眠卵萌发的比较研究

实验室内对镜湖沉积物中的轮虫休眠卵进行了萌发,共孵出轮虫47种,隶属于10科19属;其中大湖区沉积物中萌发出的轮虫40种,小湖区41种,两湖区共同种类34种.每毫升大湖区沉积物中休眠卵萌发出的轮虫平均数量为(1.1±0.1)个,显著高于小湖区的(0.4±0.0)个.在两湖区沉积物中,以3种孵化方式所萌发出的平均密度超过4.0ind./200mL的轮虫种类总计有6种,它们是多须伪前翼轮虫(Proalides tentaculates)、裂痕龟纹轮虫(Anuraeopsis fissa)、螺形龟甲轮虫(Keratella cochlearis)、裂足臂尾轮虫(Brachionus diversicornis)、臂三肢轮虫(Filinia brachiata)和萼花臂尾轮虫(Brachionus calyciflorus);其中前三种轮虫为两湖区所共有.共有的3种轮虫的孵出情况在两湖区沉积物间也存在着差异.在小湖区沉积物中,3种孵化方式下孵出的平均密度大于0.05ind./200mL的轮虫属是臂尾轮属、伪前翼轮属、龟甲轮属和龟纹轮属,而大湖区沉积物中孵出的平均密度较高的轮虫属还包括三肢轮属、巨头轮属(Cephalodella)和异尾轮属(Trichocerca);水体营养程度较高的大湖区沉积物中孵出的臂尾轮属、伪前翼轮属和龟甲轮属轮虫的密度均高于营养程度较低的小湖区.     

武汉东湖若干种轮虫休眠卵的形态观察

休眠卵是轮虫在恶劣生态条件下形成的滞育结构。本研究用光学显微镜和扫描电子显微镜对东湖14种轮虫休眠卵形态进行了观察,其中关于尾突臂尾轮虫（Brachionuscaudatus,Barrois＆Daday）、方形臂尾轮虫（Bquadridentatus,hermann）、中型晶囊轮虫（Asplanchnaintermedia,Hudson）、顶生三肢轮虫（Filiniaterminalis,Plate）的休眠卵的形态特征尚未见过报道。这些休眠卵一般卵壳较厚,颜色较深,壳表面有纹饰。不同种轮虫的休眠卵形态、壳饰各不相同,具种的特异性,但在某些轮虫,即使同一种中休眠卵形态有时亦存在较大的差异。     

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。     

镜湖沉积物中轮虫休眠卵的原位萌发

将2004年春季采于芜湖市镜湖的沉积物样品在不同季节进行原位萌发发现,除冬季未见有轮虫孵出外,其余3个季节共孵出轮虫39种,隶属于7科19属;大湖区每200ml沉积物中休眠卵萌发出的轮虫数量平均为212.2个±48.9个,显著高于小湖区的39.1个±10.3个。大湖区沉积物在夏季萌发出的小巨头轮虫(Cephalodella exigua)、大肚须足轮虫(Euchlanis dilatata)和壶状臂尾轮虫(Brachionus urceolaris)、秋季萌发出的裂足臂尾轮虫(B.diversicornis)和角突臂尾轮虫(B.angularis)以及春季萌发出的暗小异尾轮虫(Trichocerca pusilla)和等刺异尾轮虫(T.similis)分别占各季节总萌发数的51.1%、19.7%、15.7%、14.7%、11.1%、38.4%和23.7%,小湖区沉积物在夏季萌发出的多须伪前翼轮虫(Proalides tentaculates)和暗小异尾轮虫、秋季萌发出的裂痕龟纹轮虫(Anuraeopsis fissa)、尖趾单趾轮虫(Monostyla closterocerca)和大肚须足轮虫以及春季萌发出的尖趾单趾轮虫、盘状鞍甲轮虫(Lepadella patella)和暗小异尾轮虫分别占各季节总萌发数的53.9%、31.6%、18%、17%、13%、31%、24.1%和17.2%。各季节萌发出的轮虫与同季节水体中存在的轮虫种类及数量间存在的较大差异表明,那些常年存在于水体中的轮虫所产的休眠卵的萌发对其种群增长的直接贡献可能不大;而那些每年都要从水体中消失一段时间的轮虫所产的休眠卵的萌发在其种群重建中的作用可能因种类的不同而异。     

武汉东湖的轮虫

本文根据1973—1975、1979—1982年在武汉东湖进行的调查资料,并与1962—1963年他人的研究结果对比,总结了20年来,在东湖2个采样站上轮虫的种类演替和数量的变动。轮虫的种类明显地减少。Ⅰ站由1962—1963年的68种至1982年减为44种;Ⅱ站由56种减为49种。由原来Ⅰ站种类多于Ⅱ站演变为Ⅱ站多于Ⅰ站。轮虫的数量急剧增加。Ⅰ站轮虫的年平均值由1962—1963年的687个/升至1982年上升为3,555个/升;Ⅱ站由332个/升上升为1,538个/升。轮虫总数的变动曲线呈夏季和秋季二个高峰,冬、春季轮虫的数量均很低。本文从生态学的角度,对轮虫种类演替及其数量的发展趋势进行了探讨。     

武汉东湖的轮虫

本文根据1973—1975、1979-1982年在武汉东湖进行的调查资料,并与1962—1963年他人的研究结果对比,总结了20年来,在东湖2个采样站上轮虫的种类演替和数量的变动。轮虫的种类明显地减少。Ⅰ站由1962—1963年的68种至1982年减为44种;Ⅱ站由56种减为49种。由原来Ⅰ站种类多于Ⅱ站演变为Ⅱ站多于Ⅰ站。轮虫的数量急剧增加。Ⅰ站轮虫的年平均值由1962-1963年的687个／升至1982年上升为3,555个／升;Ⅱ站由332个／升上升为1,538个／升。轮虫总数的变动曲线呈夏季和秋季二个高峰,冬、春季轮虫的数量均很低。本文从生态学的角度,对轮虫种类演替及其数量的发展趋势进行了探讨。     

养鱼池轮虫休眠卵分布和萌发的研究

东北地区部分鱼场养鱼池底泥中轮虫的休眠卵,表层(0—5厘米)数量每平方米为1.2—503万个,个别池塘高达1,573万个,其中完全暴露于泥表面的数量约占1—2％。休眠卵数量差别和池塘环境条件关系密切;各泥层中的轮虫休眠卵数量呈“V”形垂直分布的趋势。萼花臂尾轮虫和角突臂尾轮虫的休眠卵在水温10—40℃;pH4.5—11.5;溶氧0.3毫克/升以上和盐度8.5％以下的条件下可以萌发。10℃为其发育的生物学零度。根据轮虫休眠卵分布和它的环境条件的关系,以及萌发的生态条件,阐述了在养鱼池中增殖轮虫所应采取的措施及其理论根据。     

养鱼池轮虫休眠卵分布和萌发的研究

东北地区部分鱼场养鱼池底泥中轮虫的休眠卵,表层(0—5厘米)数量每平方米为1．2—503万个,个别池塘高达1,573万个,其中完全暴露于泥表面的数量约占1—2％。休眠卵数量差别和池塘环境条件关系密切;各泥层中的轮虫休眠卵数量呈“V”形垂直分布的趋势。萼花臂尾轮虫和角突臂尾轮虫的休眠卵在水温10-40℃;pH4．5-11．5;溶氧0．3毫克／升以上和盐度8．5%以下的条件下可以萌发。10℃为其发育的生物学零度。根据轮虫休眠卵分布和它的环境条件的关系,以及萌发的生态条件,阐述了在养鱼池中增殖轮虫所应采取的措施及其理论根据。     

武汉东湖水生植物区系四十年间的变化与分析

本文根据作者近年的研究结果,并结合前人的有关研究资料,对东湖四十年间（１９５４－１９９４）水生植物区系组成变化进行了讨论。文中分析了东湖水生植物区系组成、东湖水生植物在中国与世界水生植物区系中的位置、东湖水生植物种属的分布区类型、单种属和寡种属的地理分布格局、东湖水生植物区系的性质、东湖与１０个湖泊水生植物种属相似性的分析。最后对东湖水生植物分类群及种类变化进行了探讨。     

武汉东湖桡足类的生态学演变

根据１９６２－１９６３,１９７４－１９７５,１９７９－１９９１年在武汉东湖进行的调查资料,考察了过去三十年内在东湖两个代表性采样站桡足类的种类组成及现存量的变化。结果表明：桡足类种类数由６０年代的１４种减少为９０年代的７种,Ｉ、Ⅱ站在种类组成的差别趋于消失。统计结果表明,东湖桡足类现存量以８０年代初、中期较高。但在水平分布格局上却发生了根本变化,由１９８７年前的Ｉ站现存量高于Ⅱ站,至１９８７年后Ⅱ站高于Ｉ站。本文还就影响东湖桡足类演变的生态因子进行了讨论。     

浙江两类饮用水源地浮游动物种类组成及其类群相关性分析

于2009年7月至2010年4月,在浙江省选取了10个水库和10个河网饮用水源地,进行4个季节的浮游动物采样调查。记录浮游动物101种(轮虫60,枝角类24和桡足类17种)。水库和河网轮虫的优势种分别为角突臂尾轮虫(Brachionus angularis)和针簇多肢轮虫(Polyarthratrigla),枝角类分别为颈沟基合溞(Bosminopsis deitersi)和长额象鼻溞(Bosmina longirostris),桡足类均为温剑水蚤(Thermocyclops)。水库中有一些能指示良好生态或水质的指示性种类。水库枝角类与桡足类群落之间周年在丰度和生物量上均有极显著的正相关关系(P<0.01),轮虫与桡足类类群之间的相关性最弱;河网枝角类与桡足类在夏、秋、冬季有显著的正相关性(P<0.05)。浮游动物类群之间的相关性程度,以水库的秋季与河网的夏季为最高。轮虫与浮游甲壳动物的种类丰富度随着饮用水源水体透明度的变化呈现相反的变化趋势。     

落叶生境蛭态轮虫物种多样性及四种中国新记录种

为研究落叶生境蛭态轮虫物种多样性,对中国8省28个落叶样品进行了调查,采样范围涵盖中国热带、亚热带及温带地区,海拔高度从3m到1500m不等,共记录蛭态轮虫3科8属29种,其中中国新记录属1属,中国新记录种4种,将中国蛭态轮虫记录由88种增加到92种.研究获取了新记录种跛足突盘轮虫(Bradyscela clauda ...     

Rotifera Recorded from China, 1893–1997, with Remarks on Their Composition and Distribution

A search of the literature on rotifers recorded from China, includes today 477 valid species names and 42 subspecies or infrasubspecific variants in 84 genera and 28 families recorded since 1893. Chinese rotifera research is reviewed, and all recorded species are listed with current taxonomic status and their first localities in China. Most of the named taxa are widely distributed or cosmopolitan, with only a small number (about 3%) possibly restricted to China. This fauna exhibits 15 endemic taxa. The composition and distribution of Chinese Rotifera are briefly analyzed. It is likely that considerably more rotifers remain to be described from China as further study to be carried on and taxonomic resolution improves.     

The Rotifera of Malaysia and Singapore with remarks on some species

Summary An intensive and extensive sampling of all types of Malaysian and Singaporean freshwaters for zooplankton gave 165 species, sub-species and varieties of Rotifera, mainly belonging to the Monogononta. Bdelloida were rarely identified. The present records bring Malaysia and Singapore in line with other well studied tropical countries as far as Rotifera records are concerned. 7 new genera and over 50 species, subspecies, varieties and forms have been added to the Malaysian and Singaporean Rotifera records and interesting and marked morphological and size variation in species from previous records, have been noted.The richest (in species) fauna of Rotifera occurs in rice fields and ponds which have a seasonal succession of dry to wet conditions and vegetation which shelters the rotifers.The Malaysian and Singaporean Rotifera fauna is typically tropical with a dominance of the genus Brachionus over temperate genera like Keratella. Also very rare or missing are typical temperate genera like Ploesoma, Notholca and Synchaeta. The dominance of Brachionus in Malaysia is less evident than expected because only a very small proportion of samples were taken in limnetic situations where Brachionus clearly dominates in the tropics.     

Bdelloid rotifers and nematodes in a small Italian stream

SUMMARY. The bdelloid rotifers and nematodes of a small clean watercourse in the area surrounding the Po river near Parma have been studied. The samples were collected at two sites 400 m apart. The species found in twelve collections of benthos between May 1977 and June 1978 were eighteen belonging to Bdelloidea and forty-seven to Nematoda (Tylenchida have not been considered). Nearly all the bdelloid species were oligosaprobic or beta-mesosaprobic; the Shannon index of diversity was 3.0 at the first site and 2.4 at the second. Among the Nematoda the dominant species were Paraplectonema pedunculatum and Paraphanolaimus anisitsi which were not previously recorded for Italy. Nearly all nematodes are microphagous; predators represent only 10% of collected specimens. Polluted water indicator species (Secernentia group) were only 3.5% of the total nematodes recorded. Most rotifers and nematodes did not show seasonal fluctuations in numbers. The two sampling sites do not seem to have substantial differences in the taxocoenosis of Rotifera and Nematoda; their percentage of similarity is 69% and 79% for the two classes respectively.     

Small-sized invertebrates in a gravel stream: community structure and variability of benthic rotifers

1. The Rotifera assemblage inhabiting the streambed surface and the hyporheic zone of a gravel stream was investigated between October 1991 and October 1992. Forty-two species of Monogononta and 27 of Bdelloidea were identified. Within these two classes, dominant species differed between the surface and the hyporheic zone. At the streambed surface, the abundance of monogonont rotifers showed a seasonal pattern with significantly higher densities in pools, whereas bdelloids showed no clear temporal trend and did not differ significantly among sites. In the hyporheic zone, the depth distribution differed among the two rotifer groups, bdelloids occurred in highest densities between 0 and 30 cm sediment depth, while monogononts were most abundant at greater depths.
2. Species composition differed greatly between successive sampling dates (min. 5 to max. 26 days) at both the streambed surface and the hyporheos. At the streambed surface and in the shallow hyporheos a significantly higher percentage of species was replaced in riffles than in pools.
3. Few measured hydrophysical variables were associated with the Rotifera assemblage structure. At the streambed surface, species richness was negatively correlated with water temperature and substratum heterogeneity, and Monogononta rotifer densities declined with water depth and substratum roughness.
4. Permutation tests carried out on temporal serial correlations showed that, at riffle sites at the streambed surface, bdelloid rotifer densities, rotifer species richness and diversity did not differ significantly from a temporal, near-random pattern. The hyporheic rotifer assemblage followed similar near-random patterns.     

Thermostable proteins in the diapausing eggs of Brachionus manjavacas (Rotifera)

Diapausing embryos (resting eggs) from brachionid rotifers are able to withstand desiccation and thermal stress. Resting eggs can remain viable for decades, and develop normally once placed in a permissive environment that allows for hatching, growth and development. The exact mechanisms of resistance are not known, although several molecules have been suggested to confer protection during desiccation and thermal stress. In this study, we have identified by mass spectrometry two thermostable proteins, LEA (late embryogenesis abundant) and VTG (vitellogenin-like), found exclusively in the resting eggs of Brachionus manjavacas. This is the first observation that LEA proteins may play a role in thermostability and the first report of a VTG-like protein in the phylum Rotifera. These proteins exhibited increased expression in rotifer resting eggs when compared to amictic females. Our data suggest the existence of alternate pathways of desiccation and thermal resistance in brachionid rotifers.     

蛭态轮虫中国新记录种及其研究展望

轮虫动物门蛭态亚纲轮虫由于其严格的孤雌生殖和低湿休眠特性而成为吸引各领域学者研究的重要类群。研究对2018年在珠海万山群岛采集的苔藓样品进行观察, 发现蛭态轮虫中国新记录种环颈敖突轮虫Otostephanos torquatus Bryce, 1913。目前国内缺少对该蛭态轮虫的详细形态描述, 文章通过对该种的形态观察以及咀嚼器扫描电镜拍摄, 阐述环颈敖突轮虫的主要分类特征。该物种重要分类依据为内腔里含有食物泡, 轮盘带有特殊环状结构, 上唇裂片呈三角形及裂片高度低于头冠高度, 咀嚼器齿式7/7。通过检测该轮虫的CO Ⅰ序列, 与基因库中已有同科同属相似种的CO Ⅰ基因序列聚类对比, 证明了该种属于敖突轮属的遗传位置。相较于其他国家对蛭态轮虫的研究成果及其在进化研究中的重要地位, 我国学者应该加强对蛭态轮虫的研究探索。     

Early contributions of molecular phylogenetics to understanding the evolution of Rotifera

The past decade has seen the application of DNA sequence data to phylogenetic investigations of Rotifera, both expanding and challenging our understanding of the evolution of the phylum. Evidence that Acanthocephala, long regarded as a separate but closely related phylum, is a highly derived class of Rotifera demonstrates the potential of molecular analyses to suggest relationships not obvious from morphological analysis. Phylogenies based on the sequence of the gene for the small ribosomal RNA suggest that rotifers and acanthocephalans are associated with Platyhelminthes and Gastrotricha, perhaps in a clade with Gnathostomula and Cycliophora; at present, this group lacks a clear morphological synapomorphy. A more complete resolution of the molecular phylogeny of Rotifera will require surveying multiple genes and several species from each clade under investigation.     

Rotifera from Saladillo river basin (Santa Fe province,Argentina)

Seventy-two taxa of rotifers, belonging to 24 genera, are recorded from Saladillo river basin for the first time. Among them twelve are new for Argentina. These species are described and illustrated. Ecological and biogeographical information is also given. kw]Key words kw]Rotifera kw]Saladillo river basin kw]Argentina