贵州桃种质资源遗传多样性的SCoT分析

应用SCoT分子标记技术对71份贵州桃种质进行遗传多样性分析,以期从分子水平上揭示其遗传多样性及资源间的遗传关系,为科学保存与利用贵州桃种质资源提供依据。结果表明:(1)16条引物共检测出192个位点,其中多态性位点数156个,多态性比例为81.25%,平均每条引物扩增位点为12个;供试材料Nei’s遗传多样性指数(H)为0.265 0±0.186 1,Shannon’s信息指数(I)为0.400 3±0.254 3,遗传相似系数变幅为0.400 0~0.852 5。(2)UPGMA聚类分析显示,在相似系数0.65处可将71份桃资源分成6类,其中2份白花桃资源、2份血桃资源、2份青桃资源分别为同名异物。研究认为贵州桃种质具有较丰富的遗传多样性,采用该分子标记技术区分了同名异物的桃资源。     

中型狼尾草种质资源遗传多样性的ISSR分析

运用ISSR标记对采自云南的25份野生种质和4份驯化新品系中型狼尾草材料进行遗传多样性分析。结果显示:(1)50条ISSR引物中共筛选出10条能扩增出清晰条带且多态性明显的引物,29份材料DNA共获得72个扩增位点,其中多态性位点62个,多态性比率为87.4%,平均每条引物扩增位点为7.2个;平均观察等位基因数(Na)、有效等位基因数(Ne)、Shannon多样性信息指数(I)和Nei’s基因多样性指数(H)分别为1.861 1、1.742 8、0.561 0和0.395 9;种质材料间的遗传相似性系数变幅为0.236~0.903,表现出丰富的遗传多样性。(2)利用UPGMA聚类分析,以遗传相似系数0.51为界,29份材料划分为4大类,但Mantel检测表明29份种质材料的遗传聚类和地理距离之间不存在显著的正相关关系(r=0.437 0,P=0.204 6)。研究结果首次从分子水平揭示了中型狼尾草的遗传多样性和变异水平,为合理地引种、驯化、保护和利用中型狼尾草野生资源提供了重要的参考依据和数据支持。     

福建省枳椇种质资源遗传多样性RAPD分析

建立和优化枳椇Hovenia acerba的RAPD反应体系,并对福建省12个种源地35份枳椇材料进行遗传多样性及亲缘关系研究。利用筛选出的10个RAPD引物共检测基因组DNA中193个位点,其中多态性位点161个(83.42%)。供试材料观测等位基因数(Na)1.8342、有效等位基因数(Ne)1.4155,Nei’s基因多样性(H)0.2493,Shannon多样性指数(I)0.3822。以遗传相似系数0.754为阈值,可将35份枳椇分成五大组。RAPD标记可有效揭示福建省枳椇种质资源的遗传多样性,所测枳椇种质资源遗传多样性丰富,极具开发利用价值。     

青钱柳种质资源多样性SRAP初步分析

为了利用分子标记方法评价青钱柳种质资源的遗传多样性,本文对青钱柳DNA的提取、SRAP扩增体系重要参数进行了优化,运用优化体系筛选多态性引物,并用1对引物对青钱柳9个种源进行了遗传多样性初步分析.研究结果建立了适于青钱柳SRAP的扩增体系;从110对SRAP引物中筛选出了13对多态性引物,运用1对引物组合Me7+Em2扩增获得21个多态性位点,多态率达100%.遗传多样性分析表明有效等位基因数(Ne)为1.342 9,平均Shannon's信息指数(I)为0.368 7,Nei's基因多样性指数(H)为0.226 7,种源的遗传分化指数Gst为0.198 3;聚类分析结果表明9个种源在遗传距离0.100处聚为3类,聚类结果和地理距离之间呈现较高的相关性.本文的研究结果表明所建立的青钱柳种质资源库具有广泛的遗传多样性,为进一步的开发利用提供了条件.     

24份铁皮石斛种质资源的ISSR分析

本文采用ISSR分子标记方法分析了24份不同地区来源铁皮石斛种质资源的遗传多样性和亲缘关系。利用筛选出的7条ISSR引物对铁皮石斛基因组DNA进行PCR扩增,共获得92条DNA条带,其中多态性条带84条,多态性比率(PPB)为91. 3%。利用POPGENE 32软件计算得出平均观察等位基因(Na)为1. 913 0,平均有效等位基因数(Ne)为1. 528 3,平均Nei’s基因多样性指数(H)为0. 310 0,平均Shannon’s信息指数(I)为0. 465 0。利用NTSYS-pc软件得出24份试验材料的遗传相似系数(GS)范围为0. 478 3～0. 913 0,聚类分析结果表明24份人工栽培居群的铁皮石斛分为3类,暗示铁皮石斛种质具有较为丰富的遗传多样性。该研究为全面掌握铁皮石斛种质资源遗传背景,选育、引种和推广优良铁皮石斛品种奠定了可靠的理论基础。     

海南岛油茶种质资源遗传多样性的SRAP分析

为了解海南岛油茶(Camellia oleifera)种质资源的遗传多样性,采用SRAP分子标记,对海南岛油茶主要分布区的31个居群进行了遗传多样性和亲缘关系分析。结果表明,海南岛油茶资源的遗传多样性低,物种水平的多态性百分率(PPB)为98.30%,Nei’s基因多样性(H)为0.222 8,Shannon信息指数(I)为0.353 8;居群水平的PPB=40.96%,观测等位基因数(Na)为1.409 6,有效等位基因数(Ne)为1.237 1, H=0.138 5, I=0.208 3,这与海南岛油茶丰富的表型多样性水平不一致。海南岛油茶资源遗传分化较大,居群间基因交流有限,不同居群间的遗传分化指数(Gst)为0.380,基因流(Nm)为0.813 91。遗传变异主要发生在居群内,有38.05%的变异存在居群间,61.95%存在于居群内。遗传距离为0.022 6～0.276 4,平均为0.107 7,居群间的亲缘关系较近。UPGMA聚类分析表明,在遗传距离为0.11处,可将31个油茶居群聚为6类,表现出明显的行政区域性,而与地理距离关系不大。因此,海南岛油茶资源遗传多样性低,亲缘关系近可能导致自交或近交不亲和,可能是海南油茶林分花量大而结实低的主要内在原因。     

新疆枸杞种质资源遗传多样性的SRAP分析

利用SRAP分子标记技术对新疆枸杞种质资源遗传多样性及亲缘关系进行研究,为新疆枸杞种质资源分类和杂交育种提供理论依据。结果显示:(1)筛选出的12对SRAP引物共扩增出310个位点,其中多态性位点264个,多态性比率平均为84.61%,引物多态性信息含量(PIC)变化范围为0.76~0.93,平均为0.83;观测等位基因(Na)、有效等位基因数(Ne)、Neis基因多样性指数(H)、Shannon信息指数(I)平均值分别为1.846 1、1.386 9、0.228 0和0.352 0。(2)聚类分析表明,供试材料间的遗传相似系数为0.590 3~0.903 2,在遗传相似性系数为0.70和0.76时,可将30份样品分别分为2大类和5个亚类;主坐标分析结果和聚类结果基本一致。研究表明,新疆枸杞种质资源遗传多样性较丰富,且野生种与栽培品种(系)间的遗传差异较大,表现出较远的亲缘关系,而栽培品种(系)间的遗传差异相对较小,表现出较近的亲缘关系。     

利用ISSR分子标记构建濒危植物水青树核心种质

基于全国26个居群的174份水青树Tetracentron sinense种质,利用14条ISSR引物,采用UPGMA聚类法进行多次逐步聚类,利用三种取样策略(随机取样策略、位点优先取样策略和偏离度取样策略)构建初始核心种质,并将各遗传多样性指标进行比较分析,从而确定构建水青树核心种质的最佳方法。利用14条ISSR引物扩增出180个条带,其观测等位基因数(Na)、有效等位基因数(Ne)、Nei’s基因多样性指数(H)与Shannon信息指数(I)分别为1.6944、1.3912、0.2321和0.3509,说明水青树具有较低的遗传多样性。采用位点优先取样策略构建的核心种质各遗传多样性指数均大于随机取样策略和偏离度取样策略。利用位点优先取样策略构建了78 份核心种质资源,保留了44.83%原种质样品,遗传多样性指数Na、Ne、H和I的保留率分别为98.69%、100.01%、99.27%和98.67%,比较完好地保留了原种质的遗传多样性和遗传变异。因此,位点优先取样策略是构建水青树核心种质的最佳取样策略。     

贵州野生猕猴桃表型遗传多样性分析

通过对146份贵州猕猴桃种质资源表型遗传多样性的研究,为贵州猕猴桃品种选育打下基础,对146份不同区域猕猴桃种质资源48个质量性状进行描述、赋值,并结合单果重等9个数量性状,使用主成分分析、聚类分析等进行综合评价。结果表明,57个质量性状和数量性状均存在丰富的多样性和变异性;146份资源的Shannon’s遗传多样性指数为1.28,从各区域遗传多样性指数可以看出,演化进程上从遗传多样性指数高的地区向低的地区进行演化;主成分分析结果显示,前14个主成分累计贡献率达75.076%,其中前6个主成分的累计贡献率达51.911%,为提高品种选育和评价的工作效率,可将猕猴桃种质资源的描述指标简化为新梢被毛、果实被毛等18个性状;聚类结果显示,贵州猕猴桃种质的欧氏距离为1.00~25.00之间,在D=19.25处,146份野生猕猴桃分为6个类群。本文有效揭示了贵州省猕猴桃种质资源丰富的多样性和亲缘关系,明确野生猕猴桃各种群间性状区分特征和部分优良资源性状的地理分布,对贵州猕猴桃种质资源的种质鉴定、保护利用和品种选育有重要意义。     

番木瓜主栽品种SCoT指纹图谱构建及遗传变异分析

利用SCoT标记对中国22个番木瓜主要栽培品种进行遗传多样性分析和指纹图谱构建,为番木瓜品种资源的鉴定和杂交亲本的选配提供技术参考。结果显示:(1)SCoT标记有效等位基因数(Ne)平均为1.47,Nei’s基因多样性指数(H)平均为0.26,Shannon’s信息指数(I)平均为0.39,表明SCoT标记具有较高的多态性检测效率。(2)聚类分析和主坐标分析结果表明,大部分番木瓜品种间的遗传相似系数为0.79~0.90,品种间遗传多样性水平较低;在相似性系数为0.75时可将所有品种分为3个组群。(3)6个SCoT引物可以将22个番木瓜品种完全区分开,每个品种都各有独特的指纹图谱,置信概率达到99.976%。     

Foreign exploration for Scirtothrips perseae Nakahara (Thysanoptera: Thripidae) and associated natural enemies on avocado (Persea americana Miller)

Scirtothrips perseae Nakahara was discovered attacking avocados in California, USA, in 1996. Host plant surveys in California indicated that S. perseae has a highly restricted host range with larvae being found only on avocados, while adults were collected from 11 different plant species. As part of a management program for this pest, a “classical” biological control program was initiated and foreign exploration was conducted to delineate the home range of S. perseae, to survey for associated natural enemies and inventory other species of phytophagous thrips on avocados grown in Mexico, Guatemala, Costa Rica, the Dominican Republic, Trinidad, and Brazil. Foreign exploration efforts indicate that S. perseae occurs on avocados grown at high altitudes (>1500 m) from Uruapan in Mexico south to areas around Guatemala City in Guatemala. In Costa Rica, S. perseae is replaced by an undescribed congener as the dominant phytophagous thrips on avocados grown at high altitudes (>1300 m). No species of Scirtothrips were found on avocados in the Dominican Republic, Trinidad, or Brazil. In total, 2136 phytophagous thrips were collected and identified, representing over 47 identified species from at least 19 genera. The significance of these species records is discussed. Of collected material 4% were potential thrips biological control agents. Natural enemies were dominated by six genera of predatory thrips (Aeolothrips, Aleurodothrips, Franklinothrips, Leptothrips, Scolothrips, and Karnyothrips). One genus each of parasitoid (Ceranisus) and predatory mite (Balaustium) were found. Based on the results of our sampling techniques, prospects for the importation of thrips natural enemies for use in a “classical” biological control program in California against S. perseae are not promising.     

Taxonomic status of the species of the green algal genusNeochloris

Komárek has recently reviewed the various species assigned to the green algal genusNeochloris Starr (Chlorococcales, Chlorococcaceae) and removed those with uninucleate vegetative cells to a new genus,Ettlia. Watanabe & Floyd, unaware ofKomárek's work, also reviewed the species ofNeochloris and distributed them among three genera—Neochloris, Chlorococcopsis gen. nov., andParietochloris gen. nov.—on the basis of details of the covering of the zoospore and the arrangement of the basal bodies of the flagellar apparatus. This paper reconciles these two treatments and makes additional recommendations at the ranks of genus, family, order, and class.     

Die GattungKarschia — Bindeglied zwischen bitunicaten Ascomyceten und lecanoralen Flechtenpilzen?

The genusKarschia, in the earlier sense, including saprophytes and parasites on lichens, has been thought to be a non-lichenized parallel genus of the lichen genusBuellia. Modern workers included it on the one hand inBuellia, on the other hand combined it with bitunicate ascomycetes. It is now proved thatKarschia is heterogeneous and contains but superficially similar members both of the genusBuellia of theLecanorales and of typical or masked bitunicateAscomycetes. Therefore, it can not be regarded as a link betweenLecanorales andDothideales. The type species ofKarschia belongs to theDothideales.

     

Systematic significance of mature embryo of bamboos

The mature embryo of seven species belonging to five genera of Indian bamboos is described. In all these the basic pattern of embryo organisation is same: the scutellar and coleoptilar bundles are not separated by an internode, the epiblast is absent, the lower portion of the scutellum and the coleorhiza are separated by a cleft and the margins of embryonic leaves overlap. The features unique to fleshy fruited bamboos are: presence of a massive scutellum, the juxtaposition of plumule and radicle and the occurrence of a bud in the axil of the coleoptile. The fleshy fruit bearing bamboos should be classified into one group, the tribeMelocanneae. Evidence is provided to recognise additional groups in the subfamilyBambusoideae.     

Phylogeny of cardinalfishes (Teleostei: Gobiiformes: Apogonidae) and the evolution of visceral bioluminescence

The cardinalfishes (Apogonidae) are a diverse clade of small, mostly reef-dwelling fishes, for which a variety of morphological data have not yielded a consistent phylogeny. We use DNA sequence to hypothesize phylogenetic relationships within Apogonidae and among apogonids and other acanthomorph families, to examine patterns of evolution including the distribution of a visceral bioluminescence system. In conformance with previous studies, Apogonidae is placed in a clade with Pempheridae, Kurtidae, Leiognathidae, and Gobioidei. The apogonid genus Pseudamia is recovered outside the remainder of the family, not as sister to the superficially similar genus Gymnapogon. Species sampled from the Caribbean and Western Atlantic (Phaeoptyx, Astrapogon, and some Apogon species) form a clade, as do the larger-bodied Glossamia and Cheilodipterus. Incidence of visceral bioluminescence is found scattered throughout the phylogeny, independently for each group in which it is present. Examination of the fine structure of the visceral bioluminescence system through histology shows that light organs exhibit a range of morphologies, with some composed of complex masses of tubules (Siphamia, Pempheris, Parapriacanthus) and others lacking tubules but containing chambers formed by folds of the visceral epithelium (Acropoma, Archamia, Jaydia, and Rhabdamia). Light organs in Siphamia, Acropoma, Pempheris and Parapriacanthus are distinct from but connected to the gut; those in Archamia, Jaydia, and Rhabdamia are simply portions of the intestinal tract, and are little differentiated from the surrounding tissues. The presence or absence of symbiotic luminescent bacteria does not correlate with light organ structure; the tubular light organs of Siphamia and chambered tubes of Acropoma house bacteria, those in Pempheridae and the other Apogonidae do not.     

Biological control of three floating water weeds,<Emphasis Type="Italic">Eichhornia crassipes,Pistia stratiotes</Emphasis>, and <Emphasis Type="Italic">Salviniamolesta</Emphasis> in the Republic of Congo

Since 1999, four specific weevils (Coleoptera, Curculionidae) were released in the Republic of Congo against three exotic floating water weeds: Neochetina eichhorniae Warner and N. bruchi Hustache against water hyacinth, Neohydronomus affinis Hustache against water lettuce, and Cyrtobagous salviniae Calder and Sands against water fern. Recoveries of exotic weevils were made from all 24 release sites except one, and all four species have established and spread (up to 800 km for water hyacinth weevils). Within a few years of releases, control of water fern and water lettuce was such that fishing and navigation could be resumed, while reductions of water hyacinth populations were only beginning.     

A molecular phylogeny of Hebeloma species from Europe

In order to widen the scope of existing phylogenies of the ectomycorrhizal agaric genus Hebeloma a total of 53 new rDNA ITS sequences from that genus was generated, augmented by sequences retrieved from GenBank, and analysed using Bayesian, strict consensus and neighbour joining methods. The lignicolous Hebelomina neerlandica, Gymnopilus penetrans, and two species of Galerina served as outgroup taxa. Anamika indica, as well as representatives of the genera Hymenogaster and Naucoria, were included to test the monophyly of Hebeloma, which is confirmed by the results. Hebeloma, Naucoria, Hymenogaster and Anamika indica cluster in a strongly supported monophyletic hebelomatoid clade. All trees largely reflect the current infrageneric classification within Hebeloma, and divide the genus into mostly well-supported monophyletic groups surrounding H. crustuliniforme, H. velutipes, H. sacchariolens, H. sinapizans, and H. radicosum, with H. sarcophyllum being shown at an independent position; however this is not well supported. The section Indusiata divides with strong support into three groups, the position of the pleurocystidiate Hebeloma cistophilum suggests the possible existence of a third subsection within sect. Indusiata. Subsection Sacchariolentia is raised to the rank of section.