我国新记录海链藻属物种的形态学和系统学研究

为了廓清我国海链藻属的物种多样性, 并丰富其分子生物学信息, 为后续的系统学研究提供基础数据, 从我国沿海分离并建立了海链藻的单克隆培养株系, 利用光学显微镜和电镜技术进行了形态学研究, 同时还对其核糖体大亚基的高变区序列进行了扩增和测序分析。结合形态学和分子生物学数据, 鉴定了我国海链藻属的2个新记录种: 狭线形海链藻Thalassiosira anguste-lineata (Schmidt) Fryxell & Hasle和碟形海链藻T. minicosmica Lee & Park。对它们的形态学特征进行了较为详尽的描述, 并与相似种进行了比较研究。此外, 还基于核糖体大亚基高变区的碱基序列信息, 分析了它们的分子系统学位置。在分子系统树上, 狭线形海链藻和碟形海链藻均不与该属模式种——诺氏海链藻T. nordenskioeldii 聚在同一分支上, 显示它们与典型海链藻属物种之间具有较大的遗传差异。分子系统树还显示, 目前基于形态学建立的海链藻属并非自然类群, 而是被骨条藻属Skeletonema、小环藻属Cyclotella、漂流藻属Planktoniella等邻近属种分隔成多个分支, 这预示着现存的海链藻属应该是一个并系类群, 在后续的系统学研究中, 或许会有较大的系统学调整, 但目前有限的分子生物学信息是相关研究推进的重要限制。     

海链藻属重要形态学特征的二次研究——以艾伦海链藻为例

海链藻属（Thalassiosira Cleve）是硅藻门中物种多样性最为丰富的大属之一,广泛分布于全球各类水体。目前沿用的海链藻属分类体系是基于形态特征建立的,尤其是电镜下的超微特征具有重要的分类价值。然而,也有研究认为某些形态特征存在不稳定或变化的情况,应对其开展二次研究和重新评估。故此,本文选择全球近岸广布种艾伦海链藻（T.allen Takano）作为典型代表,基于建立的单克隆培养株系,结合传统形态学方法和现代分子生物学技术,对其重要形态特征进行了二次研究。结果显示：（1）艾伦海链藻壳面孔纹的排列方式存在一定的变化,呈切线形或偏心状;壳缘唇形突的位置多有变化,占据一个壳缘支持突的位置、或位于两个壳缘支持突正中间、或靠近其中一个。艾伦海链藻这两个特征并不具有较高的稳定性,其分类学意义或应降低;（2）壳缘不具有肋纹,此特征相对稳定,可作为艾伦海链藻的识别特征之一;（3）艾伦海链藻具有较保守的遗传多样性,尚未发现（拟）隐形种。结合其它海链藻的形态学报道,我们认为孔纹排列方式易受环境的影响,稳定性较差,在分类时应慎重应用;壳缘唇形突的位置在少数海链藻属物种中易发生变化,分类时应视具体物种而针对性应用;支持突等突起特征较为稳定,在海链藻属物种的分类体系中仍可作为重要依据;艾伦海链藻中壳缘肋纹具有较好的稳定性,可作为分类依据,但在其它海链藻属物种中是否也具有很好的分类价值,还需要更多的研究加以验证;分子信息在形态特征上的二次研究和评价中具有重要应用价值,但目前相关分子数据的缺乏和不足限制了对其进一步的研究。本研究对重新评估艾伦海链藻形态特征的分类学价值、完善现存的分类学体系提供了参考。     

14种石斛属(兰科)植物的花粉团形态及分类学意义

利用体式显微镜和扫描电镜观察了14种石斛的花粉团形态及其表面纹饰超微特征,为该属的物种划分和系统演化提供花粉形态证据。解剖镜下,14种石斛的花药里有4枚花粉团,表面金黄油亮呈蜡质,质地坚硬。根据每种石斛的4枚花粉团的总体轮廓形态和大小,可分为3种形态(心形、近心形和长心形)和4种类型(极小花粉团,小花粉团,大花粉团和超大花粉团)。根据单个花粉团边界轮廓的曲直,可将其分为4种类型(月牙型、弓型、棍状和米粒型)。扫描电镜下,14种石斛的花粉团表面纹饰类型有5种(光滑平整型、光滑带丝状突起型、光滑不平整型、粗网纹状型和皱波状型),在广东石斛和球花石斛的花粉团表面观察到晶体的存在。花粉团的形态大小和外壁纹饰特征在种间变化明显,对澄清石斛属的分类学问题有一定意义。     

中国沟胸步甲属分类研究及一新种描述(鞘翅目： 步甲科： 壶步甲族)

【目的】沟胸步甲属Holcoderus属于鞘翅目(Coleoptera)步甲科(Carabidae)壶步甲族(Lebiini)。本研究旨在对该属在中国分布的各个种进行分类厘定。【方法】基于中国科学院动物研究所的馆藏标本以及欧洲多家博物馆的模式标本,采用形态比较学方法开展研究。【结果】共发现中国沟胸步甲属5种,其中包括新种1种(双毛沟胸步甲H. bisetus sp. n.,模式产地：云南西双版纳),中国新纪录种3种(雅沟胸步甲H. gracilis、绿沟胸步甲H. smaragdinus和红腿沟胸步甲H. aeripennis)。提供了中国所有种类的形态描述及特征图,并编制了分种检索表。【结论】至此,我国所分布的沟胸步甲属物种从此前记录的1种增加至5种。     

卫矛科沟瓣属与卫矛属的数量分类学研究

卫矛属(Euonymus L.)和沟瓣属(Glyptopetalum Thw.)的系统关系长期以来备受争议,为理清它们之间的关系,该研究选择沟瓣属12种、卫矛属17种和假卫矛属(Microtropis Wall.ex Meisn.)2种,共计31个分类单元(OTUs),测量并统计了56个形态性状,同时利用聚类分析(UP...     

国产乌头属(毛茛科)的种子形态及其系统学意义

对中国毛茛科乌头属植物57种、5变种的种子形态进行了扫描电镜观察,结果发现:(1)种皮微形态特征在属内颇为稳定,种子表皮细胞多为长方形(仅露蕊乌头的种子表皮细胞为圆形或椭圆形),具有疏密不一的瘤状纹饰;(2)种子形态在亚属水平上有较大区别,特别是其中的单型亚属——露蕊乌头亚属的种子表面具有较为复杂的网状凹陷,与牛扁亚属和乌头亚属的种子(表面相当平滑)明显不同;(3)种子形态在牛扁亚属和乌头亚属中都有明显的分化,所观察的牛扁亚属的种子可分为两个类型,乌头亚属的种子可分为4个类型.根据上述结果,讨论了乌头属种子形态的分类和系统学价值.     

凤仙花属棒凤仙亚属(凤仙花科)植物花粉形态的分类学意义

棒凤仙亚属代表着凤仙花属最先分化出的一支,以多年生草本,多于5朵花的总状花序,侧生萼片4枚,3沟花粉,心皮四室且每室具1枚种子,果实棒锤状,种子椭圆形以及三沟花粉其极面观为三角形而区别于其它种类。该亚属主要分布于中国南部,少数种类辐射分布至华中和中南半岛地区。已有报道证实花粉的形态特征对凤仙花属植物的属下分类具有重要意义,但对棒凤仙亚属的种类少有涉及。为了进一步探讨该亚属花粉的形态特征及其分类学价值,该研究应用扫描电镜技术对国产棒凤仙亚属植物的14种以及凤仙花亚属的窄萼凤仙花的花粉进行了观察。结果表明：棒凤仙亚属的花粉以单粒存在,具3条萌发沟,辐射对称,极面观为三角形或三角状圆形,花粉粒外壁具均匀的网状纹饰,网脊平滑或具波状边缘,网眼中具不同密度的颗粒状突起。棒凤仙亚属的花粉形态与水角属的花粉形态相似,表现出了其原始性;其花粉形态特征与花部形态性状等相关性差,对该亚属的组级分类意义较小,但对于该亚属的种间界定具有重要意义;而其花粉的极面观形状、赤道面观形状以及网状纹饰等变异相对稳定,对于界定该亚属具有重要的分类学价值。     

18种(1变型)鼠尾草属植物叶表皮及表皮毛微形态特征研究

鼠尾草属是唇形科中最大的属,全球有近1 000种。我国是鼠尾草属东亚分布中心,有84种,分布于全国各地,尤以西南地区最多。鼠尾草属植物具有很高的经济价值和观赏价值,但由于鼠尾草属植物分布广、种类多、形态变异大,给该属鉴定和分类学研究带来了很大的困难。此外,在采集和调查过程中发现弧隔鼠尾草亚属和荔枝草亚属的很多种类在营养生长期仅通过叶片很难鉴定。表皮毛是植物叶片上最常见的附属物,其分布特性和形态特征常作为植物鉴定和分类学研究的重要手段。该文利用光学显微镜和环境扫描电镜对18种和1变型共19份鼠尾草属植物的叶片类型、表皮细胞形状、垂周壁样式、气孔器类型和表皮毛等叶表皮微形态特征进行了观察和比较研究,为鼠尾草属的分类界定研究提供证据。结果表明:这19份鼠尾草属植物叶表皮和表皮毛形态特征在电子显微镜下表现出明显的多样性,叶表皮细胞形状为不规则形或多边形,垂周壁多数为浅波状或波状,少数为平直或弓形。气孔器为无规则型和不等细胞型,其中无规则型最为常见。样品叶表皮毛分为4个类型,盾状腺毛、头状腺毛、短非腺毛和长非腺毛。该属植物叶表皮的这些微形态特征,可为本属鉴定和分类学研究提供理论依据。     

新疆12种黄芩属植物叶表皮微形态结构的研究

应用光学显微镜和扫描电镜技术对新疆12种黄芩属植物叶片上的微形态特征进行观察。结果表明:该属植物叶的上表皮细胞形状及垂周壁式样有多种形式;而下表皮细胞形状均为不规则形,垂周壁式样均为深波形,不具分类学意义,但叶片两面分布的气孔器,在不同种间气孔大小、气孔密度、气孔指数、气孔外拱盖内缘等方面都存在着显著差异;其表皮角质层纹饰和表皮毛的微形态也各有不同;大多数植物叶片表面具腺点,其大小、分布及疏密程度也有不同。植物叶表皮上的这些微形态特征,可为探讨本属种间的分类学及亲缘关系提供一定的佐证。     

新疆14种青兰属植物叶表皮微形态结构研究

应用光学显微镜和扫描电镜,对新疆14种青兰属(DracocephalumL.)植物叶片的微形态特征进行观察,结果表明:该属植物只有宽齿青兰(Dracocephalum paulsenii Briq.)叶的下表皮细胞为多边形,其余种植物叶的上、下表皮均为不规则形;垂周壁式样有深波状、波状、浅波状、平直-弓形;气孔器均为横列型;气孔形状有椭圆形、长椭圆形、宽椭圆形、近圆形;表皮毛的类型为小刺毛、短柔毛、长柔毛、头状腺毛和盾状腺毛。在不同种间甚至是同种植物叶的上、下表皮上,气孔器的大小、气孔密度、气孔指数、气孔外拱盖内缘、表皮毛、角质层纹饰等的微形态特征都存在很大的差异,可为探讨本属种间的分类、亲缘关系和演化趋势提供理论依据。     

Morphological variability of Aulacoseira granulata (Ehr.) Simonsen (Bacillariophyceae) in the Lower Paraná River (Argentina)

In this paper we consider the morphological variation within a natural population of Aulacoseira granulata (Ehr.) Simonsen in relation to environmental factors. This species was dominant in the phytoplankton of the Lower Paraná River (Argentina) and exhibited seasonal fluctuations of cell dimensions. The mean cell diameter was directly correlated with the river water level and inversely with pH and nitrate concentrations, whereas cell length was directly correlated with transparency and nitrate concentration and inversely with suspended solids. This pattern was similar to that observed for filament length. The cell length : diameter ratio was inversely related to water level and discharge and directly related to pH, transparency, and nitrate concentration. Maximum diameters did not coincide with maximum lengths. A tendency to maintain cell volume throughout the annual cycle was observed, which probably relates to both buoyancy and photosynthetic capacity. These results associate the water ascendancy and the size recovery phases to discharge. Cells become smaller on the ebbing of the flood phase, and the decreasing depth increases the probability that the alga will be disentrained from the turbulent field. The loss during low water would act as a stimulus for auxosporulation, contributing to the production of large cells to start off the next population. Received: August 12, 2000 / Accepted: November 14, 2000     

Observations on Aulacoseira nipponica from Lake Biwa, Japan, and Aulacoseira solida from North America (Bacillariophyceae)

A recent diatom, Aulacoseira nipponica (Skvortzow) Tuji comb. et stat. nov., is described from Lake Biwa, Japan, where they had been identified previously as Aulacoseira solida (Eulenstein) Krammer. These forms are compared with populations of A. solida from North America. The Japanese species differs from the North American specimens in characteristics related to the density of striae and form of the rimoportulae.     

Morphology of Aulacoseira filaments as indicator of the aquatic environment in a large subtropical river: The Pearl River,China

To identify new indicators of aquatic environmental parameters, both qualitative (the percentages of curved filaments and filaments with ending separation spines) and quantitative morphological parameters (filament and cell size) of a dominant chain colony-forming planktonic diatom (Aulacoseira granulata) were determined in the large, subtropical Pearl River, China. The qualitative parameters mainly exhibited a spatial pattern. The percentage of curved filaments was a good bioindicator of spatial patterns because it varied along the nutrient gradient. Furthermore, the percentage of filaments with ending separation spines was a good bioindicator of seasonal variation. Although the quantitative parameters exhibited a clear temporal pattern, no single parameter could be used as a bioindicator of either spatial or temporal patterns. The link between qualitative and quantitative parameters reflected the internal adaptation mechanism of filamentous diatoms to the external environment. The methods of the present study can also be applied to ecological indicators in other aquatic ecosystems dominated by chain colony-forming diatoms.     

Pareuchiloglanis (Teleostei: Sisoridae) from the Pearl River,China with description of three new species

We describe three new species of Pareuchiloglanis. Based on a comparison of 17 valid species of Pareuchiloglanis, the genus can be divided into two groups contingent on their gill opening size and the anus position. One group, which we call the large gill opening group, has a large gill opening extending to the base of the first pectoral-fin element; the anus is obviously closer to pelvic-fin insertion than the anal-fin origin; this group includes five species distributed in the Red and Pearl Rivers, China. The other group has a small gill opening extending only to the middle base of the pectoral-fin elements; the anus is usually located at the midpoint of the pelvic-fin insertion to the anal-fin origin or slightly behind. This group includes the other 12 species, which are distributed in the Mekong and Yangtze Rivers. The large-gill-opening group can be divided into two sub-groups based on the length of the caudal peduncle. One sub-group has a long caudal-peduncle and the distance from the anal-fin origin to caudal-fin base is greater than distance from the pelvic-fin insertion. This sub-group is only distributed in the Pearl River drainage. Another sub-group has a short caudal peduncle and the distance from the anal-fin origin to the caudal-fin base is typically smaller than the distance from the pelvic-fin insertion. This sub-group is only distributed in the Red River basin of China and Vietnam. The former will be called the large-gill-opening group with long caudal peduncle in the text and only includes one species P. longicauda. During our ongoing taxonomic work of specimens collected from Nanpan-jiang and Beipan-jiang (upper Pearl River drainage in Yunnan, China), some Pareuchiloglanis specimens that had the characters of the large-gill-opening group with long caudal peduncle represent three undescribed species.     

Length-to-weight and length-to-length ratios of six cavefish species from the Pearl River Basin,South China

Length-to-weight and length-to-length ratios were estimated for six cavefishes including Yunnanilus longibarbatus, Yunnanilus bailianensis, Yunnanilus jinxiensis, Oreonectes polystigmus, Paranemachilus pingguoensis, and Paranemachilus genilepis from the upper reaches of the Pearl River, Guangxi Province, China (between 106.26E, 23.14N and 111.42E, 24.85N). The fish were captured between May and October in 2018 and 2019 using trap nets (mesh size 7 mm) set in front of selected caves at 6:30–7:30 p.m. and were hauled out at 6:30–7:30 a.m. the next day. After removal, the fish were measured and weighed immediately to the nearest 0.1 cm and 0.1 g, respectively. The regression parameter r² was between .95 and .98. The total length-to-standard length ratios were also calculated with r² ≥ .98. This study should provide a useful reference for biological studies and biodiversity conservation of cavefish.     

Description of a new species of Triplophysa (Teleostei: Nemacheilidae) from Guizhou Province,China

A new cave‐dwelling fish species Triplophysa guizhouensis is described based on specimens collected from Guizhou, China, in a subterranean system interconnected with the Hongshui River drainage. The species can be distinguished from its congeners by a combination of characters: eyes present; caudal fin with 14 branched rays; inner gill rakers of first gill arch 8–10; posterior chamber of air bladder developed; and body posterior of dorsal fin scaled. A key to species of Triplophysa in the Pearl River basin is provided.     

Butyltins in sediments and biota from the Pearl River Delta,South China

Abstract

Butyltins in sediments and biota collected from the Pearl River Delta, South China were analyzed by a gas chromatograph–atomic emission detector (GC-AED). The concentrations of tributyltin (TBT) in the sediments ranged from 1.7 to 379.7 ng/g dry weight. Their spatial distribution suggested that shipping activities, especially shipyards were mostly responsible for the TBT contamination in the region. A good linear relationship was observed between the DBT (dibutyltin)/TBT and MBT (monobutyltin) /TBT ratios of the samples in the Pearl River, the Pearl River estuary and the West River, suggesting that TBT in these areas came from similar sources but had undergone a different extent of degradation. The butyltins in the Macao waters seemed to have undergone a different degradation process. All TBT concentrations of the fish, mussel and shrimp samples collected in this study were below the seafood tolerable average residue level (TARL).     

珠江广州河段轮虫的时空分布研究

2004年4月-2007年3月,对珠江广州河段轮虫群落结构的时空变化进行了三年的调查研究。调查期间,共发现轮虫56种。优势种为裂痕龟纹轮虫(Anuraeopsis fissa),微型多突轮虫(Proalides subtilis),西式三肢轮虫(Filinia novaezealandiae),角突臂尾轮虫(Brachionus angularis),尾突臂尾轮虫(Brachionus caudatus),暗小异尾轮虫(Trichocerca pusilla),蛭态目(Bdelloidea sp.)和萼花臂尾轮虫(Brachionus calyciflorus)。调查发现,珠江径流量对轮虫密度有重要影响。在丰水期,两个采样站点(分别为中大码头和黄埔码头)的轮虫密度变化不大,而在枯水期,位于下游的黄埔码头的轮虫密度显著低于上游的中大码头。轮虫的密度高峰出现在秋季(9月底至12月初)。中大码头轮虫的最高峰出现在2004年12月初,为5975ind./L;黄埔码头的轮虫高峰出现在2004年4月中旬,为5877ind.·L^-1。轮虫密度变化范围为4~5975 ind.·L^-1。中大码头轮虫密度的平均值为1627±233 ind.·L^-1;而黄埔码头的平均值为1051±147 ind.·L^-1。     

A new freshwater heteronemertean from the Zhujiang (Pearl River), People's Republic of China

A new genus and species of freshwater heteronemertean, Amniclineus zhujiangensis, from the Zhujiang (Pearl River), People's Republic of China, is described and illustrated. The species is placed in the family Lineidae along with the existing freshwater heteronemertean taxa, with which its anatomy is compared.     

Length-weight relationships of four fish species from the lower reaches of the Nujiang River and its tributaries in China

As one of the largest Southeast Asian rivers, flowing through China, Myanmar, and Thailand, the Nujiang (Salween) River contains a unique and rich diversity of fish species. In the present study, we investigated the length–weight relationships (LWRs) of four fish species (Pteronemacheilus meridionalis, Devario shanensis, Exostoma gaoligongense, and Glyptothorax granosus) collected from the lower reaches of the Nujiang River and its tributaries (24.175N~25.842N, 98.861E~98.903E), including the Mengboluo, Kungong, Luomingba and Laowo rivers in southwest China. Specimens were collected by using drift gill nets (100 m length × 1.5 m depth or 3 m depth, mesh-size: 1 cm-5 cm), cast nets (6.5 m, mouth opening: 35 × 45 cm², mesh-size: 4 mm) , and an electric shocker apparatus (12 V, 200 Hz) from different regions in the Nujiang River basin in September and October 2019 and June and September 2020. Before the collected fishes were placed in formalin, standard length (SL) and net weight (W) were measured respectively to the nearest 0.1 cm and 0.1g, respectively. Based on searches of the FishBase database and other relevant scientific literature, this study provides a new record of maximum size for P. meridionalis and LWRs for the four fish species.