细鳞斜颌鲴三个群体形态差异

将传统形态学数据与现代框架数据相结合,分析了细鳞斜颌鲴3个群体(龙窝湖群体、梁子湖群体和淮河群体)的形态差异,探讨了它们的形态亲缘关系。方差分析表明,3个群体间8个可数性状参数差异不显著(P0.05)。聚类分析显示,龙窝湖群体与梁子湖群体首先聚为一类,然后再与淮河群体相距。在28个测量参数中挑选7个对判别贡献较大的参数建立判别函数,判别效果极显著(P0.01),判别准确率93.55%～100%,综合判别率96.81%,通过判别函数可将这3个群体很好地区分开。主成分分析概括出方差贡献率较大的3个主成分,累计方差贡献率为82.99%。主成分1主要反映鱼体躯干部的形态变化,方差贡献率52.83%;主成分2主要反映鱼体头部的形态变化,方差贡献率22.22%;主成分3主要反映鱼体尾柄部的形态变化,方差贡献率7.94%。主成分1和2二维平面图显示,虽然龙窝湖群体和梁子湖群体有少量重叠区域,但3个群体还是可以清晰分开的。3个群体间形态性状的差异系数均小于1.28,群体间尚未达到亚种差异水平。     

甘蔗品种(系)叶片形态特征数学分析

本文对48份甘蔗品种(系)的叶片形态特征进行主成分、聚类和判别分析.结果表明,品种(系)间的叶片形态特征差异达到极显著水平(P＞0.01);主成分分析选出了3个主成分,方差累积贡献率达到97.52%,叶长、叶宽及形态因子分别是第一、二、三主成分的主导因子;在聚类分析基础上用判别分析选出对甘蔗品种(系)叶片形态分类有极显著影响的面积、长度、宽度、周长、长宽比及形态因子参数,同时建立了4个判别能力较高的判别模型.     

基于转录组的池蝶蚌系统发育及其遗传分析

池蝶蚌(Hyriopsis schlegelii)和三角帆蚌(Hyriopsis cumingii)的亲缘关系一直存在争议, 为了更深入地对淡水珠蚌进行系统发育分析, 研究对池蝶蚌及其3个近缘物种三角帆蚌、褶纹冠蚌(Cristaria plicata)和背角无齿蚌(Anodonta woodiana)的转录组进行了比较分析。对它们共有单拷贝同源基因进行多序列联配后计算这4种淡水珠蚌之间的遗传距离, 结果表明池蝶蚌和三角帆蚌的遗传距离只有0.00746(小于1%), 而其他淡水珠蚌之间的遗传距离几乎是它的10倍(平均大于6%)。系统发育分析表明, 小方蚌亚科与无齿蚌亚科大约在5144万年前发生分歧, 而池蝶蚌和三角帆蚌发生分化的时间大约在424万年前。进一步的遗传差异分析鉴定了池蝶蚌转录组中的特有基因, 其中KEGG 通路富集的结果表明这些基因主要富集在免疫细胞膜分子和蛋白消化吸收等通路上。同时, GO注释结果表明有很多特有基因与池蝶蚌的优良性状相关, 如与发育相关的生长发育、系统发育和动物器官发育等生物学过程, 及与免疫相关的免疫系统过程、抗原处理和呈递等生物学过程。以上结果表明, 池蝶蚌和三角帆蚌具有更近的亲缘关系, 它们可能是同一物种的不同亚种或不同种群, 这对淡水珠蚌种质资源的保护和遗传育种具有重要参考意义。此外, 相比于三角帆蚌, 池蝶蚌可能具有一些与生长发育及免疫相关的特有基因, 这为探究相关的分子机制提供了线索。     

四川裂腹鱼和重口裂腹鱼形态差异的多元分析

通过聚类分析、判别分析和主成分分析3种多元分析方法,对乌江总溪河89尾四川裂腹鱼(Schizothorax kozlovi)和岷江青衣江33尾重口裂腹鱼(S.davidi)的10个常规可量性状与20个框架性状进行了比较研究。聚类分析结果显示,3次采集的四川裂腹鱼聚为一支,而重口裂腹鱼单独为一支;主成分分析结果显示,提取的8个主成分对总方差的累计贡献率为73.762%,贡献率大的性状集中在吻端和躯干后侧;通过两次判别分析,最终建立四川裂腹鱼和重口裂腹鱼两个判别方程,综合判别率为100%。研究结果显示,四川裂腹鱼和重口裂腹鱼是独立的两个种,在形态上的主要差异体现在吻端和躯干后侧,运用多元分析方法能有效地将其区分开来,而3次采样的四川裂腹鱼为同一种群。     

淡水育珠蚌褶纹冠蚌血细胞的初步研究

国外关于海产双壳贝血细胞形态与功能的研究虽然较多,但对于淡水育珠蚌褶纹冠蚌的血细胞却无研究报道,国内关于软体动物血细胞的研究甚少,对于育珠蚌血细胞只笼统地称之为游走细胞,颗粒细胞等,对它们的种类和形态无详细的描述。为此作者对褶纹冠蚌的血细胞进行了形态学的初步观察,以期对今后的研究工作提供参考。     

甘蔗品种（系）叶片形态特征数学分析

本对48份甘蔗品种(系)的叶片形态特征进行主成分、聚类和判别分析。结果表明,品种(系)间的叶片形态特征差异达到权显水平(P＞O．01);主成分分析选出了3个主成分,方差累积贡献率达到97．52％,叶长、叶宽及形态因子分别是第一、二、三主成分的主导因子;在聚类分析基础上用判别分析选出对甘蔗品种(系)叶片形态分类有权显影响的面积、长度、宽度、周长、长宽比及形态因子参数,同时建立了4个判别能力较高的判别模型。     

板栗和锥栗天然同域居群的叶表型变异研究

对分布于湖北省秭归县境内的一个由169株板栗（Castanea mollissima）和281株锥栗（C.henryi）组成的天然同域居群的20个叶表型性状的变异进行了研究。根据叶片背面和叶柄的被毛情况及叶缘形状3个定性性状,在总共450个个体中,共得到18个（4%）中间过渡类型个体。利用17个数量性状进行逐步判别分析（SDA）表明：根据定性性状得到的中间型个体中分别有7个和11个被归入板栗和锥栗;板栗和锥栗在叶形上的差异较大,有8个数量性状被选入判别方程,判别方程对板栗和锥栗的判别准确率都达93%以上,判别结果较为理想;综合20个表型性状进行主成分分析（PCA）,构建了3个主成分,主成分1和2的贡献率分别为53.5%和18.7%,累计贡献率达72.2%。前2个主成分的散布图中,有6个（1/3）中间型个体位于板栗和锥栗的重叠分布区域,可能是二者之间存在杂交的表型证据。     

背角无齿蚌外套膜的组织化学研究

背角无齿蚌(Anodonta woodiana elliptica)在我国分布很广,是我国三种淡水育珠蚌之一。它所形成的珍珠微带金黄色,具有特殊的风格。四川省安岳县自1971年开始使用背角无齿蚌进行珍珠养殖以来,获得了不少经济利益,并积累了一些育珠经验。为了进一步探讨珍珠形成机理,以利于提高珍珠质量,从而获得更多优质珍珠。我们在对我国淡水育珠河蚌外套膜组织学和染色体等研究的基础上,又采用组织化学方法,对背角无齿蚌外套膜细胞中的核酸、糖类、酶等生物大分子物质作了组织化学方面的一些观察研究。     

中国蚌科线粒体16S rRNA序列变异及系统发育

首次测定了中国淡水贝类———蚌科 (Unionidae) 1 3个属代表种类的线粒体 1 6SrRNA部分序列。用Clustal X排序软件进行 1 6SrRNA序列的对位排列 ,序列总长度为 30 5— 32 0bp。通过Mega 2 0软件对所得线粒体 1 6SrRNA片段序列进行比较 ,共发现 1 0 8个碱基存在变异 ,其中包括 77个简约信息位点 ,并用“Pairwisedistance”计算了各属间的相对遗传距离。以贻贝为外类群 ,采用Mega 2 0软件中的“Neighbore Joining”法得到惟一一个分子系统树 ,系统树各分支的置信度由“Bootstrap”1 0 0 0循环检验。结果表明 :分布于中国的蚌科形成三个明显的类群 ,第一个类群 ,包括帆蚌属、蛏蚌属、丽蚌属和尖锄蚌属 ;第二个类群 ,由矛蚌属、扭蚌属、裂脊蚌属、鳞皮蚌属、尖嵴蚌属、楔蚌属和珠蚌属组成 ;第三个类群只包括无齿蚌和冠蚌两个属。由此可以看出 ,它们有可能分别隶属于三个不同的亚科 ,即小方蚌亚科 (帆蚌属、蛏蚌属、丽蚌属和尖锄蚌属 )、无齿蚌亚科 (无齿蚌属和冠蚌属 )和珠蚌亚科 (矛蚌属、扭蚌属、裂脊蚌属、鳞皮蚌属、尖嵴蚌属、楔蚌属和珠蚌属 ) ,由此证明小方蚌亚科在中国的存在 ,并且 ,对几个属的分类位置作了调整。其中鳞皮蚌属和蛏蚌属原来属于无齿蚌亚科 ,根据线粒体 1 6SrRNA的结果 ,前者应该放     

淡水珍珠功能成分的水提取工艺

为更好的利用淡水珍珠中的功能成分,减少提取过程中对蛋白等成分的影响。研究了以pH值为3.0的醋酸与醋酸钠水提取珍珠中功能成分的工艺。采用固定床提取方法,以pH值为3.0的醋酸水溶液提取珍珠中水溶性成分,在选定的最适工艺条件下,珍珠中蛋白质提取率达86.3%,水解为氨基酸的蛋白质仅为0.036%。同时提取得到了一种新功能成分,经初步结构确定为黄酮类化合物,提取率达80.8%,为淡水珍珠的利用提供了基础。     

Molecular characteristics and expression of calmodulin cDNA from the freshwater pearl mussel, Hyriopsis schlegelii

Calmodulin (CaM) is a multifunctional intracellular calcium ion receptor protein that participates in a range of cellular processes, including calcium metabolism in mussels. To investigate the role of CaM in freshwater mollusk shell calcium metabolism, the full-length CaM cDNA was isolated from the freshwater pearl mussel, Hyriopsis schlegelii (referred to as hsCaM) using SMART RACE technology. The full-length hsCaM was 855 bp in size, containing a 70-bp 5'-untranslated sequence, a 447-bp open reading frame, a 309-bp 3'-untranslated sequence, and a 26-nucleotide long poly(A) tail. The hsCaM mRNA expression in different mussel tissues was examined using real-time PCR. The hsCaM mRNA was found to be ubiquitously expressed, but far more abundant in the gill, foot, and mantle than in the posterior adductor muscle. Real-time PCR was also used to determine hsCaM mRNA expression levels in mantle tissues of H. schlegelii at different ages. No significant differences between one-, two-, and three-year-old mussels were detected, but expression increased in four-year-old mussels and then decreased in five-year-old mussels. CaM appears to be involved in calcium regulation of the mantle in four-year-old mussels, which may secrete more mother of pearl during pearl culture.     

Strategies for the conservation of endangered freshwater pearl mussels (<Emphasis Type="Italic">Margaritifera margaritifera</Emphasis> L.): a synthesis of Conservation Genetics and Ecology

Freshwater pearl mussels (Margartifera margaritifera L.) are among the most critically threatened freshwater bivalves worldwide. The pearl mussel simultaneously fulfils criteria of indicator, flagship, keystone and umbrella species and can thus be considered an ideal target species for the process conservation of aquatic ecosystem functioning. The development of conservation strategies for freshwater pearl mussels and for other bivalve species faces many challenges, including the selection of priority populations for conservation and strategic decisions on habitat restoration and/or captive breeding. This article summarises the current information about the species’ systematics and phylogeny, its distribution and status as well as about its life history strategy and genetic population structure. Based on this information, integrative conservation strategies for freshwater mollusc species which combine genetic and ecological information are discussed. Holistic conservation strategies for pearl mussels require the integration of Conservation Genetics and Conservation Ecology actions at various spatial scales, from the individual and population level to global biodiversity conservation strategies. The availability of high resolution genetic markers for the species and the knowledge of the critical stages in the life cycle, particularly of the most sensitive post-parasitic phase, are important prerequisites for conservation. Effective adaptive conservation management also requires an evaluation of previous actions and management decisions. As with other freshwater bivalves, an integrative conservation approach that identifies and sustains ecological processes and evolutionary lineages is urgently needed to protect and manage freshwater pearl mussel diversity. Such research is important for the conservation of free-living populations, as well as for artificial culturing and breeding techniques, which have recently been or which are currently being established for freshwater pearl mussels in several countries.     

Impacts of invasive crayfish (Pacifastacus leniusculus) on endangered freshwater pearl mussels (Margaritifera laevis and M. togakushiensis) in Japan

The invasive alien crayfish Pacifastacus leniusculus is considered harmful to freshwater pearl mussels Margaritifera laevis and M. togakushiensis. It also often colonises mussel habitats in Japan. In order to test the negative effects of alien crayfish on mussels, we evaluated the predation impact of signal crayfish on freshwater pearl mussels in vitro. We tested the relationship between the survival/injury rates of mussels and crayfish predation with respect to different sizes of mussels (four classes based on shell length: 10, 30, 50 and 70 mm). Crayfish selectively fed on the flesh of the 10-mm size class mussels after breaking their shells. The shell margins of mussels in all size classes were injured by crayfish. Results also showed that crayfish particularly injured the 50-mm size class of mussels. This observation could be attributed to this mussel size being the most suitable shell size (29.56–37.73 mm in carapace length) that the crayfish can effectively hold. This study shows that the presence of invasive crayfish reduces freshwater pearl mussel populations by damaging the shell margins and/or killing the mussels. This negative impact of invasive crayfish not only decreases the mussel population but could also limit mussel recruitment, growth and reproduction.     

Freshwater pearl mussels show plasticity of responses to different predation risks but also show consistent individual differences in responsiveness

Animals often show behavioural plasticity with respect to predation risk but also show behavioural syndromes in terms of consistency of responses to different stimuli. We examine these features in the freshwater pearl mussel. These bivalves often aggregate presumably to reduce predation risk to each individual. Predation risk, however, will be higher in the presence of predator cues. Here we use dimming light, vibration and touch as novel stimuli to examine the trade-off between motivation to feed and motivation to avoid predation. We present two experiments that each use three sequential novel stimuli to cause the mussels to close their valves and hence cease feeding. We find that mussels within a group showed shorter closure times than solitary mussels, consistent with decreased vulnerability to predation in group-living individuals. Mussels exposed to the odour of a predatory crayfish showed longer closures than control mussels, highlighting the predator assessment abilities of this species. However, individuals showed significant consistency in their closure responses across the trial series, in line with behavioural syndrome theory. Our results show that bivalves trade-off feeding and predator avoidance according to predation risk but the degree to which this is achieved is constrained by behavioural consistency.     

Regional monitoring of freshwater pearl mussel <Emphasis Type="Italic">Margaritifera margaritifera</Emphasis> in the County of Norrbotten,Sweden

A total of 16 freshwater pearl mussel Margaritifera margaritifera rivers out of 64 known freshwater pearl mussel rivers are included in the Administrative County of Norrbotten regional monitoring program. First surveys were done in 1994 and the results show that only three rivers have viable populations according to national criteria despite little visible human impact and that juvenile mussels (<50 mm in length) have been found in all rivers at every occasion. The results also indicate that there might be “missing years” for juvenile recruitment suggesting that freshwater pearl mussel populations at the extreme end of the species range might be dependent on “golden moments” in order to keep up viable populations. Deeper knowledge and better tools for determining viable populations might be necessary in order to make the right decisions on how to manage the rivers and the freshwater pearl mussel populations.     

High levels of multiple paternity in a spermcast mating freshwater mussel

Multiple paternity is an important characteristic of the genetic mating system and common across a wide range of taxa. Multiple paternity can increase within‐population genotypic diversity, allowing selection to act on a wider spectre of genotypes, and potentially increasing effective population size. While the genetic mating system has been studied in many species with active mating behavior, little is known about multiple paternity in sessile species releasing gametes into the water. In freshwater mussels, males release sperm into the water, while eggs are retained and fertilized inside the female (spermcast mating). Mature parasitic glochidia are released into the water and attach to the gills of fish where they are encapsulated until settling in the bottom substrate. We used 15 microsatellite markers to detect multiple paternity in a wild population of the freshwater pearl mussel (Margaritifera margaritifera). We found multiple paternity in all clutches for which more than two offspring were genotyped, and numbers of sires were extremely high. Thirty‐two sires had contributed to the largest clutch (43 offspring sampled). This study provides the first evidence of multiple paternity in the freshwater pearl mussel, a species that has experienced dramatic declines across Europe. Previous studies on other species of freshwater mussels have detected much lower numbers of sires. Multiple paternity in freshwater pearl mussels may be central for maintaining genetic variability in small and fragmented populations and for their potential to recover after habitat restoration and may also be important in the evolutionary arms race with their fish host with a much shorter generation time.     

水体Ca2+对三角帆蚌珍珠质沉积的影响

为研究不同水体Ca2+浓度(10-80 mg/L)下三角帆蚌生长和珍珠质沉积量和晶体结构的变化, 采用鱼蚌混养的养殖模式养殖10周。结果表明, 1龄幼蚌生长的适宜Ca2+浓度为40 mg/L, 2龄未植片三角帆蚌生长的适宜Ca2+浓度为40-70 mg/L, 2龄植片三角帆蚌珍珠沉积的适宜Ca2+浓度为40 mg/L。拉曼光谱分析和珍珠层小片的扫描电镜观察结果表明, 适宜Ca2+浓度影响三角帆蚌珍珠质沉积可能是通过促进外套膜组织有机基质分泌从而调节CaCO3晶体形成和生长实现的。研究结果提示, 在三角帆蚌生长快速季节, 养殖水体中添加一定的钙源如生石灰等将有利于蚌体和珍珠的生长。同时研究结果也为加快珍珠培育, 提高珍珠品质提供理论依据和实践操纵手段。     

The impact of land use on the mussel Margaritifera margaritifera and its host fish Salmo trutta

Today, land use impacts a major proportion of all streams. Here, landscape features in corridors along streams and water chemical factors were analyzed in relation to recruitment of the threatened freshwater pearl mussel (Margaritifera margaritifera) and its host fish the brown trout (Salmo trutta). Mussel recruitment and trout density were negatively related to forest clear-cuts. Mussel recruitment was negatively related to water color and turbidity. Therefore, the threats to the mussel may be severe, as low mussel recruitment may be caused by direct effects on the juvenile mussels and indirect effects on the host fish. High proportions of lakes and ponds were found to be positive for recruitment and for trout, and deciduous forest was positively related to trout. The combination of investigations at different scales at the landscape level and at in-stream levels may be applicable to find threats to other threatened species. The results indicate that forestry activities may negatively affect recruitment of freshwater pearl mussels and its host fish. Reductions of forestry activities and the retaining of intact quantity and quality of the riparian zones next to streams, both for the mussel and its host fish may be important conservation measures to restore freshwater pearl mussel populations.