喜马拉雅-横断山区优越虎耳草谱系地理学研究

利用叶绿体DNA非基因编码区rpl20-rps12和trnL-trnF作为分子标记,对喜马拉雅-横断山区优越虎耳草13个居群151个个体进行谱系地理学研究,旨在揭示优越虎耳草现有的遗传结构及其演化历程。共检测到19个单倍型,其中63%的单倍型为居群特有单倍型。研究还发现,优越虎耳草居群总的遗传多样性较高（H_t=0.868）,居群内平均遗传多样性较低（H_s=0.466）。分子变异分析（AMOVA）表明,优越虎耳草居群57.37%的遗传变异来自居群内,居群间遗传变异为42.63%。居群遗传分化系数N_st大于G_st（N_st=0.463,G_st=0.438,P>0.05）,但不显著,表明优越虎耳草在其整个分布范围内没有明显的谱系地理结构。中性检验结果表明,Tajima's D为负值（-1.348 32,P>0.05）而Fu's F_s*为正值（18.915 72,P>0.05）,但均不显著,结合歧点分布分析发现该物种在整个分布范围内未经历过居群扩张。此外,在本研究中优越虎耳草遗传多样性和核苷酸多样性较高的居群及大量特有单倍型在整个分布范围内随机分布,符合"微型避难所"假说。优越虎耳草居群在冰期可能随气候波动而发生分布范围的不断变化,最终在相互隔离的"高山岛屿"中发生异域分化,导致大量特有单倍型产生。因此,推测优越虎耳草与其生境中的乔木和灌木可能具有相似的谱系地理历史,它们可为优越虎耳草提供微型避难所而使之在冰期时保留下来。     

青藏高原特有植物青海当归的谱系地理学初探

为探讨第四纪冰期气候波动对青藏高原多年生草本植物青海当归地理分布格局形成的影响,检测了青海当归16个居群147个个体的核糖体内转录间隔区(ITS)的序列变异,共发现了7个单倍型.结果表明除松潘居群外其余15个居群都拥有单倍型H1,青藏高原边缘的居群拥有6种ITS单倍型,其中5种为私有单倍型.谱系关系分析显示单倍型H1为较古老的单倍型,AMOVA分析表明,居群间的变异占了总变异量的67％,居群遗传分化显著,并且存在较明显的谱系地理结构(NST＞GST,P＜0.05).我们认为青海当归在第四纪冰期最大一次冰期来临时退缩到青藏高原边缘的避难所,冰期后在扩张过程中经历了奠基者效应形成了如今的分布格局.     

祁连山区特有物种黑虎耳草的居群遗传多样性研究

利用叶绿体基因(rbcL和trnS-G)及核糖体DNA内转录间隔区(ITS),对祁连山区狭域分布的特有物种黑虎耳草8个居群(115个个体)进行遗传多样性研究,旨在揭示黑虎耳草的居群遗传结构及其历史进化过程。结果表明:(1)所有取样个体共检测到4个cpDNA单倍型和9个ITS单倍型,其中祁连山东南部的居群固定较多的单倍型和特有单倍型,而西北部居群只固定少数几个广泛分布的单倍型,且遗传多样性普遍较低。(2)基于cpDNA数据和ITS数据的分子变异分析(AMOVA)显示,遗传变异主要来源于居群内。(3)基于cpDNA数据的中性检验表明,Tajima’s D(-1.012 30,P 0.05)和FuLi’s D*(-2.066 77,P 0.05)均为负值,均不显著;歧点分布分析结果显示,黑虎耳草居群经历过近期的扩张事件。根据物种现有遗传分布格局推测,黑虎耳草在第四纪冰期时退缩到祁连山东南部的边缘避难所,间冰期或冰期后回迁到祁连山西北部地区,在回迁过程中由于奠基者效应导致祁连山西北部的居群仅固定少数广泛分布的单倍型,并呈现出较低的遗传多样性;由于居群较小且相互隔离,该物种经历了严重的瓶颈效应和遗传漂变,导致该物种总遗传多样性(H_T)和居群平均遗传多样性(H_S)远低于虎耳草属其他青藏高原-喜马拉雅广域分布的物种。     

青藏高原东北部黄缨菊的谱系地理学

黄缨菊（Xanthopappus subacaulis）是青藏高原地区一种特有的高山草甸药用植物。为探讨第四纪冰期气候波动对黄缨菊居群遗传结构和空间分布格局的影响,对黄缨菊20个居群、123个个体的叶绿体DNA片段（psbA-trnH、rbcL和psbI-psbK）进行测序和数据分析。结果表明：黄缨菊居群共检测到6个单倍型,其中H1为古老单倍型,除居群P7外其余居群均具有单倍型H1,H3、H5和H6为特有单倍型,单倍型H3为居群P7的私有单倍型,单倍型H5和H6只存在于居群P18,单倍型H2和H4主要存在于青海湖流域的居群;总的遗传多样性（H_e）和核苷酸多样性（π）分别为3.101和0.008 903;居群间遗传变异（68.98%）大于居群内遗传变异（31.02%）,居群间遗传分化较高（F_ST=0.689 85,P<0.01）;居群遗传分化系数N_ST（0.727）大于G_ST（0.656）（P>0.05）,表明黄缨菊在分布区域内不存在明显的谱系地理结构;错配分布和中性检验结果显示,黄缨菊居群可能经历过近期扩张。据此,推测第四纪冰期黄缨菊可能在青海湖流域和甘肃临潭地区存在微型避难所,认为第四纪气候变迁及青藏高原隆升塑造了黄缨菊的现代地理分布格局。     

臭柏天然居群遗传多样性及演变历史分析

为了合理有效地保育天然臭柏(Juniperus sabina L.)种质资源,追溯和阐释其分布格局的历史成因,本文对我国内蒙古自治区、陕西省、甘肃省和青海省共10个天然臭柏居群388个个体的核糖体内转录间隔区(ITS)序列片段进行测序分析。结果显示:臭柏ITS序列总长度为1089 bp,共含有25个变异位点,定义32个单倍型,其中H4和H6单倍型为共有单倍型;分子变异分析(AMOVA)显示,臭柏居群变异主要来源于居群内,遗传变异为95.04%,而居群间遗传变异仅4.96%,居群间差异水平极显著(F ST=0.0496,P<0.001);Network单倍型网络分析表明,H4和H6为古老单倍型,其他单倍型是由他们衍生而来;遗传分化系数N ST(0.072)0.05)。推测臭柏起源于第三纪中新世(Miocene)中期约12.38 Mya,在第四纪冰期可能存在多个小型避难所。沙埋产生不定根的扩繁能力和较好的有性更新环境可能是沙地居群遗传多样性高于山地居群的决定性因素。     

基于叶绿体DNA变异研究高山植物偏花报春的种内谱系地理结构

横断山地区是许多温带植物的冰期避难所。为揭示该地区分布物种的亲缘地理结构, 检测了该地区特有、分布相对较为普遍的偏花报春Primula secundiflora的叶绿体trnL-trnF和rps16区序列变异。研究了11个居群109个个体, 一共发现了15种单倍型。只有一种单倍型为3个居群所共有, 其他单倍型都只存在于单个居群内。总的遗传多样性较高(HT=0.966), 但居群内遗传多样性较低(HS=0.178)。尽管种内形态十分一致, 居群间却存在高水平的遗传分化(FST=0.976)。NST (0.982)显著高于GST (0.816), 表明偏花报春在居群间存在明显的亲缘地理结构。单倍型聚成四个主要的分支: 三个分支的单倍型分布在北部, 而另一分支的单倍型分布在南部。四个分支的隔离分布表明该物种在冰期存在多个避难所。未发现在其他温带物种中广泛存在的间冰期或者冰期后物种分布范围的统一扩张现象。但是, 在气候变迁过程中由于居群增长-缩小反复发生, 多数居群的遗传多样性降低。这些推断也被巢式分支分析所证实, 距离隔离而导致的限制性基因流以及异域片断化被认为是该物种现有单倍型分布格局形成的主要原因。这种独特的谱系地理结构主要是由于气候变迁与该地区复杂的地质环境相结合造成的。     

南方红豆杉谱系地理学研究

通过对南方红豆杉18个居群499个个体叶绿体基因组的trnL-F片段进行RFLP分析,共检测到6个叶绿体DNA单倍型,其中除台湾居群外的17个居群都包含有单倍型H1和H2;黄山及临安居群除单倍型H1、H2外,还分别各有1个特有单倍型。谱系关系分析显示,单倍型H1、H2为较古老的祖先单倍型。AMOVA分析显示,变异主要存在于居群内,居群间的遗传分化程度较低(26.39%)。嵌套分支分析(NCA)显示,单倍型分布与地理分布存在轻度的地理相关性,南方红豆杉现在的遗传结构可能源于居群的片段化效应,台湾居群可能是由于曾经的居群片段化而隔离或长距离扩散所致;在第四纪冰期,中国东、南部地区可能存在2个以上南方红豆杉的避难所。     

青藏高原高山流石滩特有植物绵参的谱系地理学研究

绵参(Eriophyton wallichii)是中国青藏高原地区高山流石滩特有植物.为探讨第四纪冰期气候波动对青藏高原高山流石滩植物居群遗传结构以及谱系历史的影响,检测了绵参20个居群187个个体的核糖体内转录间隔区(ITS)的序列变异,共发现19个单倍型,且结果表明大部分居群拥有独自的单倍型.AMOVA分析表明,居群间的变异占了总变异量的89.54％,居群遗传分化指数很高(GST=0.863,NST=0.957),但无明显的谱系结构.我们推测这种独特的谱系地理结构可能主要是由于高山流石滩独特的地形和环境及“孤岛效应”形成的,与先前研究过的青藏高原植物不同,绵参呈现出高度分化的遗传结构,常常呈现出“一个居群,一种单倍型”的模式,这可能是由于第四纪冰期及间冰期尽管绵参的分布范围有扩大和收缩,但始终由于特殊的高山生境和流石滩基质,导致了该物种长期以来居群间很少有基因交流并一直处于隔离状态,造成了现在这样的谱系地理结构.     

横断山区高山绣线菊的谱系地理学研究

横断山区作为青藏高原东南部主要的一个冰期避难所,第四纪冰期气候的变化对该地区的植物地理分布和居群遗传结构都产生了重要的影响。为了揭示该地区物种分布的分子系统地理学结构,选取在该地区广泛分布的一种高山灌木-高山绣线菊的叶绿体trnL-trnF序列进行研究。采集了15个居群182个个体进行测序,共发现7个单倍型。总的遗传多样性较高(HT=0.809),但居群内遗传多样性较低(HS=0.236)。分子变异分析(AMOVA)结果表明分布区内高山绣线菊的遗传变异主要存在于居群间(84.48%),且居群间的遗传分化很高(GST=0.708,FST=0.84476,NST=0.863),有着显著的谱系地理学结构(NST>GST,P<0.01)和较低的居群间平均基因流(Nm=0.09)。单倍型的系统进化树和进化分支网络分析得到了相似的拓扑结构,7种单倍型都按照地理分布聚为三支:横断山区西部、横断山区东部以及两者的交接地带。本研究推测该物种在横断山区存在多个冰期避难所,而没有表现出大规模的种群集体扩张和迁移的现象。青藏高原隆升、第四纪气候的反复波动以及横断山区特殊的地理环境使得原来连续的居群片段化,并发生范围扩张,从而塑造了高山绣线菊的现代生物地理分布格局。     

横断山地区海仙报春的谱系地理学研究

由于横断山地区特殊的地理效应,第四纪冰期气候的反复变化对该地区植物的地理分布和居群遗传结构产生重要影响。为了揭示该地区分布的物种的谱系地理结构,检测了该地区特有的、生于湿地环境的植物海仙报春（Primula poissonii）的叶绿体trnL—F和trnT—L两个序列变异。共对13个居群167个个体的两个叶绿体片段进行测序,共发现11个单倍型。三种单倍型被共享,其他单倍型都只存在于单个居群内。分子变异分析（AMOVA）结果表明分布区内海仙报春的遗传变异主要存在于居群间（99．08％）,且居群间的遗传分化很高（GST=0．916,FST=0．99077,NST=0．973）,有着极显著的谱系地理学结构（NST〉GST,P〈0．01）和较低的居群间平均基因流（Nm=0．08）。结合嵌套分支分析（NCA）,本文的研究结果推测该物种在冰期可能存在多个避难所,并没有表现出大多数温带植物在第四纪冰期所经历过的种群集体扩张和迁移的现象,异域片段化被认为是该物种现有单倍型分布格局形成的主要原因。海仙报春的谱系地理结构是气候的反复波动和横断山特殊的地理环境互相作用的结果。     

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.     

Molecular phylogeny of Phebalium (Rutaceae: Boronieae) and related genera based on the nrDNA regions ITS 1+2

Parsimony analyses of the internal transcribed spacer regions of nuclear ribosomal DNA (ITS 1 & ITS 2) for 38 taxa sampled from the Phebalium group (Rutaceae: Boronieae) and two outgroups confirm that, with the exception of Phebalium sensu stricto and Rhadinothamnus, six of the currently recognised genera within the group are monophyletic. The data indicate that Phebaliums. str. is paraphyletic with respect to Microcybe, and Rhadinothamnus is paraphyletic with respect to Chorilaena. Rhadinothamnus and Chorilaena together are the sister group to Nematolepis. Drummondita, included as an outgroup taxon, clustered within the ingroup as sister to Muiriantha and related to Asterolasia.The phylogeny suggests that the evolution of major clades within a number of these genera (e.g. Phebalium) relates to vicariance events between eastern and south-western Australia. Leionema is an eastern genus, with the most basal taxon being the morphologically distinct Leionema ellipticum from northern Queensland. Leionema also includes one species from New Zealand, but this species (as with some others) proved difficult to sequence and its phylogenetic position remains unknown. Taxonomic changes at the generic level are recommended.The authors wish to thank Paul G.Wilson, PERTH, for advice and discussion, and Paul Forster, BRI, for collecting and providing material of Leionema ellipticum. The project was supported by a Melbourne University Postgraduate Award (to BM), the Australian Biological Resources Study (ABRS), Australian Systematic Botany Society and Wolf Den (Australia) Investments.     

New species and new combinations in Peruvian Orchidaceae

seventeen new species and combinations are proposed in the generaChondrorhyncha, Cischweinfia, Cochlioda, Eloyella, Encyclia, Kefersteinia, Koellensteinia, Macroclinium, Rodriguezia, Solenidiopsis, andStenia. All new species are illustrated. A key is provided for 2-flowered species ofMacroclinium, PeruvianSigmatostalix, and PeruvianStenia. Solenidium (Solenidiopsis) peruvianum Schltr. is lectotypified.     

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.     

Entwicklungsgeschichte und Ultrastruktur von Pollenkitt und Exine bei nahe verwandten entomophilen und anemophilen Angiospermensippen derAlismataceae,Liliaceae, Juncaceae,Cyperaceae, Poaceae undAraceae

Some closely related members of the monocotyledonous familiesAlismataceae, Liliaceae, Juncaceae, Cyperaceae, Poaceae andAraceae with variable modes of pollination (insect- and wind-pollination) were studied in relation to the ultrastructure of pollenkitt and exine (amount, consistency and distribution of pollenkitt on the surface of pollen grains). The character syndromes of pollen cementing in entomophilous, anemophilous and intermediate (ambophilous or amphiphilous) monocotyledons are the same in principal as in dicotyledons. Comparing present with former results one can summarize: 1) The pollenkitt is always produced in the same manner by the anther tapetum in all angiosperm sub-classes. 2) The variable stickiness of entomophilous and anemophilous pollen always depends on the particular distribution and consistency of the pollenkitt, but not its amount on the pollen surface. 3) The mostly dry and powdery pollen of anemophilous plants always contains a variable amount of inactive pollenkitt in its exine cavities. 4) A step-by step change of the pollen cementing syndrome can be observed from entomophily towards anemophily. 5) From the omnipresence of pollenkitt in all wind-pollinated angiosperms studied one can conclude that the ancestors of anemophilous angiosperms probably have been zoophilous (i.e. entomophilous) throughout.

     

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.     

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.     

安徽牯牛降的丝孢菌Ⅰ

本文报导作者采自安徽枯牛降自然保护区的18种丝孢菌,分属于5个属,其中有3个新种:牛皮冻生尾孢(Cercospora paederiicola),山鸡椒假尾饱(Pseudocercospora litseae-cubebae),鸡血藤生假尾孢(P. millettiicola)和2个中国新纪录。文中对新种进行了描述及绘图,新记录种作了简要说明。研究的标本保存在中国科学院微生物研究所真菌标本室(HMAS)。     

Changes of dung beetle communities from rainforests towards agroforestry systems and annual cultures in Sulawesi (Indonesia)

Little is known about how tropical land-use systems contribute to the conservation of functionally important insect groups, including dung beetles. In a study at the margin of Lore Lindu National Park (a biodiversity hotspot in Central Sulawesi, Indonesia) dung-beetle communities were sampled in natural forest, young secondary forest, agroforestry systems (cacao plantations with shade trees) and annual cultures (maize fields), each with four replicates (n = 16 sites). At each site we used 10 pitfall traps, baited with cattle dung, along a 100 m transect for six 3-day periods. The number of trapped specimens and species richness at the natural forest sites was higher than in all land-use systems, which did not significantly differ. Each land-use system contained, on average, 75% of the species richness of the natural forest, thereby indicating their importance for conservation. However, a two-dimensional scaling plot based on NESS indices (m = 6) indicated distinct dung beetle communities for both forest types, while agroforestry systems and annual cultures exhibited a pronounced overlap. Mean body size of dung beetles was not significantly influenced by land-use intensity. Five of the six most abundant dung beetle species were recorded in all habitats, whereas the abundance of five other species was significantly related to habitat type. Mean local abundance and number of occupied sites were closely correlated, further indicating little habitat specialisation. The low dung beetle diversity (total of 18 recorded species) may be due to the absence of larger mammals in Sulawesi during historical times, even though Sulawesi is the largest island of Wallacea. In conclusion, the dung beetle fauna of the lower montane forest zone in Central Sulawesi appears to be relatively robust to man-made habitat changes and the majority of species did not exhibit strong habitat preferences.