杭州西湖初步治理后的浮游植物现状

本文记录了杭州西湖初步治理后的浮游植物种类组成、相似性、数量分布与环境理化因子的关系,以及根据指示种类评价了西湖水质。在1985年2月至1986年2月周年调查的20个站位中,共鉴定了浮游植物7门92属229种、变种和变型;其中蓝藻门19属39种;绿藻门35属87种8变种1变型;硅藻门24属54种7变种1变型等。西湖浮游植物的数量分布以外湖最高,年均值为529.1×105个/L,三潭内湖最低,仅1.76×105个/L。全湖每升水样含浮游植物细胞密度年均值为614×105个,并且以蓝藻占绝对优势,年均值为423×105个/L,绿藻、硅藻次之,分别为97.3×105个/L和77×105个/L。不同站位浮游植物种类组成的相似性指数值(sorensen 公式)在51.3-85.3范围。       

Mollusks associated to the submerged roots of the red mangrove,Rhizophora mangle (L.), in the Gulf of Santa Fe,Sucre State,Venezuela

A qualitative and quantitative monthly study of the mollusks community associated to the submerged roots of the red mangrove, Rhizophora mangle (L.), between October of 1998 and September of 1999, in six stations of the Gulf of Santa Fe, (Sucre State, Venezuela). Were collected 4,704 specimens, 45 species of mollusks were identified (22 gastropods, 15 bivalves and 8 chitons). The most abundant species were: Crassostrea rhizophorae, Isognomon bicolar, I. alatus and Brachidontes exustus. The highest values in diversity and evenness, and the smallest dominant values, were in the stations three and four, while the opposed happened in the stations one and two. The analysis of likeness showed that in the first five stations the space variations in the composition of the community are bigger than the temporary variations, while in the station six the temporary differences prevail. They were factors that could be important to determine the structure of the community, as vicinity to other ecosystems and/or specific biological aspects of the species like adaptations to fluctuating conditions, nutritious habits and migration in search of shady and protected atmospheres.     

千佛山自然保护区种子植物区系特征研究

在对千佛山自然保护区详细调查的基础上,对其种子植物的科、属分布区类型进行了统计分析。结果表明:(1)保护区内种子植物丰富,共153科767属2494种;(2)优势科、属明显;(3)区系起源古老;(4)种子植物地理成分复杂,吴征镒划分的中国种子植物属的15大分布类型在千佛山均有分布;(5)种子植物区系在科和属级水平上均显示出温带性质,温带分布属475属,占总属数的61.9%;(6)特有属、种丰富。     

四川被子植物区系特征的初步研究

四川地区被子植物区系188科1493属8711种及1252变种,全球50％以上的科都有代表,与毗邻地区及世界植物区系有着广泛而密切的联系。区系古老而原始,珍稀孑遗类群丰富;单型或少种的科属众多,含100种以上的大科和大属也十分繁荣;含5种以下的属占76.89%,但占总属数约22.64%的多种属和大属是区系的主体,包含区系总种数的63.28%。科的分布类型有明显热带性质,属、种的分布类型反映出典型的亚热带属性。优势现象明显,特有类群和表征类群丰富。该地区被子植物区系对中国乃至东亚都有代表性。     

The taxonomy and ecology of the vascular plant flora of Singapore: a statistical analysis

A total of 2277 species of vascular plant in 868 genera and 158 families are recorded as native to the Republic of Singapore. This flora consists of 174 pteridophytes (7.6% of the total), eight gymnosperms (0.4%), 590 monocots (25.9%) and 1505 dicots (66.1%).Median values of species per family, genera per family and species per genus are 5, 2 and 1, respectively. The most abundant 'families' and genera in terms of species are Orchidaceae (196 spp.), Pteridophyta (174 spp.), Rubiaceae (140 spp.), Euphorbiaceae (116 spp.), Gramineae (100 spp.) and Eugenia (46 spp.), Ficus (43 spp.), Dendrobium (33 spp.), Bulbophyllum (29 spp.) and Cyperus (29 spp.). Trees constitute 37.2% of the flora, shrubs 9.8%, herbs 25.9%, climbers 14.0% and epiphytes 13%.Euphorbiaceae and Rubiaceae dominate the woody flora; pteridophytes, Gramineae and Cyperaceae the herbs; Rubiaceae, Palmae and Annonaceae the climbers and Orchidaceae and pteridophytes the epiphyteS. Species confined to coastal habitats comprise 11.1% of the total flora; 73.5% are lowland forest species and the remaining 15.5% are non-tree species of open and frequently-disturbed sites. The vascular plant of flora of Bukit Timah Nature Reserve, the largest remaining patch of primary rain forest in Singapore, is also analysed. Its flora is similar to that of the forest component of the complete Singapore flora. The Singapore flora, in comparison with other tropical floras, is highly diverse, but appears depauperate in epiphytes and climbers.     

Survey of the mycoflora of barley grains in Egypt

The fungi of 40 samples of barley grains collected from Upper Egypt were estimated using the dilution- and the grain-plate methods. 33 genera and 109 species, in addition to 2 varieties of Aspergillus nidulans, one variety of Aspergillus flavus and one variety of Penicillium cyclopium were identified. The spectrum of fungal genera and species collected by the grain-plate method (29 genera and 94 species+3 varieties) was broader than by the dilutionplate method (27 genera and 71 species+3 varieties), but the order of frequency of occurrence of fungal genera and species was basically similar in the two methods. The most frequent genera were Aspergillus (25 species+3 varieties), Penicillium (32 species+1 variety), Rhizopus (2 species), Alternaria (2 species), Fusarium (6 species) and Drechslera (5 species) and were represented (as assayed by the grainplate method) in 100 %, 77.5 %, 85 % 62,5 %, 60 % and 52.5 % of the samples constituting 60.4 %, 10.2 %, 7.7 %, 3.7 %, 5 % and 2.3 % of the gross total count of fungi respectively. From the preceding genera A. niger, A. fumigatus, A. flavus, A. sydowii, P. notatum, P. citrinum, F. oxysporum, F. moniliforme, F. solani, R. stolonifer, A. alternata and D. spicifera were the most frequent.     

海南岛吊罗山种子植物区系分析

吊罗山位于海南岛东南部 ,约 1 8°5 0′N,1 0 9°5 0′E,为北热带地区 ,其种子植物区系共有种子植物1 71科、846属、1 90 0种 (裸子植物 4科 5属 1 0种 ,被子植物 1 67科 841属 1 890种 )。区系分析表明 :(1 )地理成分以泛热带、热带成分占绝对优势 (非世界属总数的 84.2 9% ) ;(2 )纯热带成分不形成区系和植被的表征 ,许多泛热带、热带种类已接近其分布北限 ;山地成分表现出热带、亚热带 -温带成分相互渗透的特点 ;(3 )该区系在海南岛整体区系中占重要位置 ,特有现象较突出 ,有海南岛地区特有属 4个 ,其它中国特有属 6个 ;吊罗山包括邻近的陵水县有 2 3 7个海南岛地区特有种 ,占全部 5 3 6个海南特有种 (变种 )的 44.2 2 % ;吊罗山特有种 5 2个 ,占海南全部特有种的 9.7% ,这表明该区系在海南森林区系中具重要意义。     

大亚湾澳头水域浮游植物群落结构及周年数量动态

对1997年至1998年广东省大亚湾澳头水域的浮游植物群落进行调查和分析。结果发现浮游植物65属198种;硅藻在种类组成和数量上都比甲藻占有优势,存在春季和秋季高峰,主要优势类群依次是角毛藻、骨条藻、拟菱形藻等;甲藻只存在春季高峰,代表种类有裸甲藻、原甲藻等。主要优势种类的生长与调查水域的盐度没有明显关系,但全年水温的季节性变化对优势种类的消长影响显著。Simpson多样性指数、Shannon-Weaver多样性指数、均匀度的年平均值分别是0.611、2.107、0.557,多样性指数没有明显的季节变化规律和水平分布规律。       

长江口附近海域春季浮游硅藻的种类组成和生态分布

2002年春季,在长江口附近海域典型赤潮高发区28个大面站位采集了53个样品,从中共鉴定出隶属于31个硅藻属的80个种和变种;其中种类多样性较高的属为圆筛藻属(Coscinodiscus),有17个种,斜纹藻属(Pleurosigma),有8个种和变种;数量上较优势的种为柔弱拟菱形藻(pseudo-nitzschia delicatissma),为3．48×10^3cells·L-1,占28．54％;具槽直链藻(Melosira sulcata),为1．43×10^3cells·L-1,占16．98％;尖刺拟菱形藻(Pseudo-nitzschia pungens),为0．71×10^3cells·L-1,占9．85％．它们在大部分站位中都有出现;柔弱拟菱形藻和尖刺拟菱形藻的高细胞密度区主要出现在1230E断面的站位,而具槽直链藻则主要出现在长江口的31～32°N断面的站位．浮游硅藻总细胞丰度变化于0．43×10^3～23．3×10^3cells·L-1,平均4．61×10^3cells·L-1;在123°E、30．5°N的DDl5站位,无论表层还是中层,浮游硅藻总细胞丰度均最高(表层,1．85×10^4cells·L-1;中层,2．33×10^4cells·L-1)．从水平分布看,浮游硅藻呈不均匀分布态势,从垂直分布看,大部分站位的表层浮游硅藻丰度高于中层．     

世界红树植物区系

探讨了世界红树林植物区系的种类组成及其特点。确认全世界共有红树植物16科24属84种(含12变种)，其中真红树为11科16属70种(含12变种)，半红树为5科8属14种。东方类群有14科18属74种(含12变种)，以／legiceras，Osbornia，／legialitis，Bruguiera，Ceriops，Kandelia，Scyphiphora和。Nypa等属为特征；西方类群有5科6属10种，具有单种特有科皮利西科Pelliceraceae以及laguncularia属。中国红树植物区系有12科15属26种(含1变种)，其中特有种4种。海南的红树植物种类最为丰富，占全国的96．2％；广东次之，占42．3％。台湾记载的红茄苳(Rhizophoram,ucronata)其实为红树榄R．stylose之误。     

Peracarid composition,diversity and species richness in the area of the Northeast Water polynya,East Greenland (Crustacea,Malacostraca)

During the ARK XI-2 expedition with RV Polarstern in September/October 1995, a transect of epibenthic sledge (EBS) samples was taken in the area of the Northeast Water Polynya off the Greenland coast, from the shelf down into the deep sea. A total of 85,304 specimens of Peracarida were collected at seven stations. These individuals comprised 45 families, 103 genera and 180 species. With regard to abundance, Cumacea occurred with highest numbers, 31,269, followed by Isopoda, Amphipoda, Mysidacea and Tanaidacea. Species richness was highest in Amphipoda with 94 species, followed by Isopoda with 43 species, Cumacea with 20 species, Tanaidacea with 15 and Mysidacea with 8 species. Species richness was highest at the shallowest station 37-016 and lowest at the deepest station 37-021, whereas the opposite pattern was found for abundance. Diversity and eveness were highest at the southernmost station and lowest at the deepest station. Amphipoda occurred more frequently at the shallower stations, while Cumacea were very frequent at the deepest station. Numbers of species were lowest for Cumacea at the deepest station, while Amphipoda and Isopoda generally occurred with high species richness at all stations. On the basis of the species composition stations were compared.     

Fish species diversity as indicator of pollution in Ikpoba River, Benin City, Nigeria

The composition and distribution of fish in the Ikpoba reservoir were investigated. A total of fifty-seven species of fish belonging to thirty-nine genera and twenty-three families were recorded. Of these, 46 species were recorded at the upstream station, 35 at the reservoir, 24 at the slope and 32 at the downstream station. The percentage compositions were 81%, 61%, 42% and 56% respectively. There were 21 ubiquitous species while the distribution of the other species showed variability indicating effects of habitat condition. Species diversity indices showed that the upstream section was richer, more diverse with species more evenly distributed than the other stations. Heavy metal analysis of the dominant fish species showed higher mean levels than the background levels. Metal contamination factor and bioaccumulation quotient were variable in the fishes and in the stations but followed a ranked order of 3 > 2 > 4 > 1 by station. Comparison of stations using ANOVA revealed a significant difference (P < 0.05) between the upstream and the slope stations.     

朝鲜北部的苔藓植物

朝鲜是同我国一江之隔的友好邻邦,它有着很多与我国东北地区共同的植物种类。因此,对朝鲜苔藓植物的研究,为进一步研究我国东北地区苔藓植物种属的起源、演化和分布区等具有重要的意义。笔者于1979年7月17日至8月29日,曾以中国科学院植物分类学赴朝考察组的组员身份,到朝鲜进行了苔藓植物学方面的考察并收集了有关资料。根据这些标本资科和有关文献,加以分析和研究后写成了本文。     

Notes on the Orchid Flora in the Hengduan Mountain Region,China

The Hengduan Mountain Region on the south-eastern fringe of the Qinghai- Xizang (Tibet) Plateau is located in W. Sichuan, N. W. Yunnan and E. Xizang, with a wide area of juxtaposition from the east to the west, the mountains extending and the rivers flowing from the north to the south. In this paper it covers an area from Daojie, Wayao, Yingping, Yangbi, Dali of Yunnan and Dukou of Sichuan in the south, to Banbar, Dengqeu, Shenda of Tibet and Serxu, Dainkog, Shuajingsi and Nanping (Jiuzhaigou) of Sichuan in the north, and from Lharong, Baxoi and Zayü of Tibet in the west, to Maowen, Wenchuan, Mt. Erlang, Mt. Emei and Xichang of Sichuan in the east (Fig. 1.). The Gongga Mountain is the highest in the region, its summit being at an altitude of 7556m, whereas the Dadu River Valley in the eastern part of the area is only 1150 m above sea level. Therefore, the relative height is about 6400 m in the region. The Hengduan Mountain Region is well-known for its various topography, complex natural conditions and rich flora. The floristic composition and features of orchids in Hengduan Mountain Region. 1. The species of orchids are abundant in the region. As we know so far, orchids in the Hengduan Mountain Region comprise 91 genera and 363 species with 9 varieties, and thus it is one of concentration centres of orchids in China, making up 56.17% of the total number of orchids genera in China, only less than in Yunnan and Taiwan, and 34.87% of the total number of orchids species in China, only less than in Yunnan and Sichuan. 2. The orchids genera in the Hengduan Mountain Region are complex in geographical components as indicated below: (1) Four geneva are endemic to China and one of them is endemic to the region. (2) Fourteen genera are of the north temperate distribution pattern, 2 of the Old World temperate one, 18 of the East-Asian one (including Sino-Himalayan and Sino-Japanese) and 3 of the East-Asian-North American one. (3) Twenty one genera belong to the tropical Asian distribution pattern, 3 to the tropical Asian-tropical African one, 13 to the tropical Asian-tropical Australian one, 1 to the tropical Asian-tropical South American one, 8 to the Old World tropical one and 2 to the pantropical one. (4) Two genera are cosmopolitan. The analysis of genera: Fourty eight genera (containing 151 species with 4 varieties) of the tropical distribution occur in the region, among which Calanthe and Cymbidium distributed in the temperate region, and Bulbophyllum and Peristylus in the subtropical part of China are comparatively abundant (with over 10 species), but the other 25 genera are monospecific and 11 genera each contain only 2-3 species. Some epiphytic genera mainly distributed in tropical Asia and belonging to tropical florestic elements, such as Vanda, Luisia, Schoenorchis, Flickingeria, Monomeria, Kingidium, Acampe, Phalaenopsis, Thrixspermum, Eria, Taeniophyllum, and terrestrial genera, such as Aphyllorchis, Collabium, Mischobulbum, Paphiopedilum, Thunia, Brachycarythis, Satyrium, Corybas, Geodorum, Zeuxine, Tropidia, have the Hengduan Mountain Region as the northern limit of distribution. Of 151 species with 4 varieties, 41 species with 4 varieties are endemic to China, and 14 species with 3 varieties of them are endemic to the area, making up 3.86% of the total in the region under discussion. There are 41 genera (containing 189 species with 5 varieties) of the temperate distribution, which occur in the region. Among them Platanthera (22 species with 1 variety), Cypripedium (17 species), Herminium (16 species), Amitostigma (15 species with 1 variety), Orchis (12 species), Hemipilia (8 species with 1 variety), Neottianthe (4 species), Gymnadenia (4 species), Diphylax (3 species), Bletilla (3 species), have the Hengduan Mountain Region as the distribution centre and differentiation centre. Among the 189 species with 5 varieties, 111 species with 5 varieties are endemic to China, and 54 species with 5 varieties are endemic to the area, making up 14.88% of the total of orchids in the Hengduan Mountain Region. Although the number of temperate distribution genera is smaller than that of tropical distribution ones, several points may be mentioned: (1) The Hengduan Mountain Region is distribution centre and differentiation centre of a number of temperate genera in China, and is the northern limit of many genera mainly distributed in the tropics. (2) The number in the former category is obviously larger than that in the latter. (3) Endemic species in the former category in the area are over three times as many as those in the latter. The differentiation of species of the temperate distribution genera is obviously stronger than the tropical ones, which characterizes the orchid flora in the area as the temperate one. The life forms of genera. The orchid flora in the Hengduan Mountain Region so far known comprises 91 genera, among which 51 are terrestrial, 32 epiphytic and 8 saprophytic, thus with the terrestrial one dominant. The analysis of species: The orchid flora in the Hengduan Mountain Region so far known comprises 363 species with 9 varieties. Their distribution patterns and floristic components, to which they belong, are indicated as follows: (1) Fifty four species, belonging to 33 genera, are widespread, covering the whole East Asian Region, but 6 of them are endemic to China. (2) Forty four species, belonging to 27 genera, are the elements of the Sino-Japanese Subregion, but 22 species of them are endemic to China. (3) One hundred and ninety five species with nine varieties, belonging to 53 genera, are the elements of the Sino-Himalayan Subregion under discussion: (A) Four species (i.e. Aphyllorchis alpine, Listera divaricata, L. pinetorum and Oreorchis micrantha) are distributed in the Himalayan Region and S. E. Xizang (Tibet), western part of this region. (B) Twenty five species, belonging to 17 genera, are distributed in N. W. Yunnan and the Himalayan Region (Appendix, 1.). (C) Sixteen species, belonging to 11 genera, are distributed in the Himalayan region and W. Sichuan. Among them 6 species occur only with Mt. Emei as the easternmost limit and 10 species occur in the region west of Mt. Emei. (D) Ten species, belonging to 9 genera, are distributed in the Himalayan region, this region and S. Shaanxi, S. Gansu or S. E. Qinghai. (E) Eight species, belonging to 6 genera, are distributed in the Himalayan region and this region. Among them 6 species have their range extending eastwards to Guizhou and 2 species eastwards to Guangxi. (F) Five species, belonging to 5 genera, having their range extending from this region southwards to N. Burma. (G) One handred and twenty seven species with nine varieties are endemic to China behind discussion. (4) (A) Three species (i.e. Anoectochilus moulmeinensis, Bulbophyllum forrestii and Liparis chapaensis) are distributed in Indo-China, Burma and the region. (B) Nine species, belonging to 7 genera, are distributed in Indo-China, N. E. India and this region. (C) Forty six species, belonging to 21 genera, are distributed in Indo-China, the Himalayan Region and this region (Appendix, 2.). (D) Twelve species, belonging to 11 genera, are distributed in Indo-China and this region (Appendix, 3.) 3. The vicarism is obvious in the orchid flora of the Hengduan Mountain Region. There are 10 species-pairs (in genera Calanthe, Tropidia, Anoectochilus, Mischobulbum, Bulbophyllum, Gymnadenia, Pogonia, Tipularia, Tulotis, Orchis, etc.) of the horizontal vicarism and 7 species-pairs (in genera Epigeneium, Epipogium, Platanthera, Pogonia, etc.) of the vertical vicarism in the region. 4. The endemic species are prolific in the region. In the orchid flora of the Hengduan Mountain Region there are 155 species and 9 varieties endemic to China: (1) Six species are widespread in the whole East-Asian Region. (2) Twenty two species are the elements of the Sino-Japanese Subregion. (3) One hundred and twenty seven species with nine varieties are the elements of the Sino-Himalayan Subregion. Among them 69 species with 5 varieties are endemic to the region (Appendix, 4.), making up 19% of the total in the region; other 58 species with 4 varieties are distributed in the region and neighbouring regions or provinces of it (Appendix, 5.). 5. Remarkable differentiation of the orchid flora in the Hengduan Mountain Region is shown by evident vicarism and abundance of endemic elements, exampled by Amitostigma, Herminium, Orchis, Cypripedium, Platanthera, etc. and one group of Platanthera, which is confined to the south fringe of the Xizang (Tibet) Plateau-Hengduan Mountain Region. The group consists of 12 species, of which one (P. edgeworthii) is distributed in the Western Himalayas from Hazara in Pakistan to Kumaun in India, and all the other 11 species (i.e.P. stenantha, P. bakeriana, P. roseotincta, P. deflexilabella, P. longiglandula, P. exilliana, P. chiloglossa, P. leptocaulon, P. platantheroides, P. clavigera and P. latilabris) occur in China, with 3 of them (i.e.P. deflexilabella, P. longiglandula and P. chiloglossa) endemic to China. According to their structure of gynostemum and form of labellum they belong to Platanthera without question, although they are different from the other members of Platanthera in stigma convex (not concave) and sepals mammillary-ciliate, stigma exhibits a series of evolutionary trends in part of species, from stigma single, convex, elliptic and located near rear of spur mouth (in P. stenantha) to stigma single, suddle, and located near front of spur mouth (in P. bakeriana) and to stigma double, separate and located at front of spur mouth in the other ten species. The group in Platanthera is only confined to the area from the south fringe of the Xizang (Tibet) Plateau to the Hengduan Mountain Region. It seems that the genus has been affected by intense lift of the area, causing variation and differentiation and giving rise to the group due to the long-term natural selection. Mt. Emei in Sichuan Province is the eastern limit of distribution of the group, where there are three spcies, among which two (P. deflexilabella and P. longiglandula) are endemic to the mountains. In addition, among Risleya (1 species), Diphylax (3 species) and Diplomeris (2 species), three genera typical of distribution in the Sino-Himalayan Subregion, Risleya and Diphylax have Mt. Emei as their eastern limit. Eleven species, belonging to elements of the SinoJapanese Subregion, occur only from Japan to Western Sichuan with Mt. Emei as the western limit. Among nine species, belonging to elements of the Sino-Himalayan Subregion, six occur from the Himalayas to W. Sichuan and three of them are endemic to the Hengduan Mountain Region, with Mt. Emei as their eastern limit of distribution. There are eight endemic species and one variety of orchids in Mt. Emei, making up about 11.59% of the total endemic species in the Hengduan Mountain Region. Orchid floristic elements in Mt. Emei are obviously different from those in Mt. Jinfo, the former being mainly of the Sino-Himalayan Subregion, while the latter being mainly of the Sino-Japanese Subregion. From the distribution patterns of the orchid floristic elements in the Hengduan Mountain Region and Eastern China, the Emei Mountain is considered important for drawing a boundary line between the Sino-Japanese Subregion and the Sino-Himalayan Subregion. The discussion may be summarized as follows: the floristic features of the orchid flora in the Hengduan Mountain Region are: (1) rich in species, complex in geographical components, eminent vicarism and differentiation, and prolific in endemic species; (2) terrestrial life form is dominant one; (3) mainly consisting of temperate and subtropical East-Asian elements, es pecially, elements of Sino-Himalayan Subregion, though with some tropical elements and elem-ents of other regions.     

The microphytobenthos of Königshafen—spatial and seasonal distribution on a sandy tidal flat

A microphytobenthic species composition of a tidal flat in the northern Wadden Sea was analysed regarding cell numbers and biomass (in carbon units). The three sampling sites differed in tidal inundation from 15 cm to about 90 cm water depth at high tide. The sediment was sandy at all three stations. A cluster analysis revealed a separation of the benthic diatoms into three areas: aNereis-Corophium-belt, a seagrass-bed and theArenicola-flat. Small epipsammic diatoms were most abundant and dominated the microalgal biomass. A microphytobenthic “spring bloom” even started beneath the ice cover of the flat in January. Lowest values of cell numbers and biomass of benthic microalgae were found in summer. Highest values were measured in the uppermost area (Nereis-Corophium-belt), and only here was an autumnal increase of benthic microalgae found. Further cluster analysis within each of the three areas revealed seasonal differences although the majority of species were present all year round. Many species were most abundant in spring, and some showed a bimodal distribution (spring-autumn) in the year of investigation.     

神农架维管植物区系初步研究

本文为神农架维管植物区系的初步研究结果,扼要报道了本区系现知的2638种(包括种下等级),分隶193科850属;粗略分析了850属的分布区类型,表明本区系以温带分布特别是北温带分布为主要成份的性质;介绍了本区系一些主要的古老属种,世界单种属47属,在中国为单种属的有33属,分布于该地区的中国特有属43属及中国列入珍稀保护植物49种。通过对木本植物的统计(有99科290属1103种,其中乔木属128属),显示出该地区是中国北温带木本植物,特别是乔木属种最丰富的地区之一。     

Seasonal dynamics of genus Alexandrium (potentially toxic dinoflagellate) in the lagoon of Bizerte (North of Tunisia) and controls by the abiotic factors

Some species of the genus Alexandrium are known as potential producers of saxitoxin, a neurotoxin that causes the paralytic shellfish poisoning (PSP) syndrome. Blooming of these species, especially in shellfish farms can affect the aquaculture production and harm human health. Seasonal dynamics of Alexandrium spp. abundance in relationship to environmental factors was investigated from November 2007 to February 2009 at six stations in the Bizerte lagoon, an important shellfish farming area situated in SW Mediterranean. The sampling stations represented different hydrological and trophic conditions: one station TJ (Tinja) is affected by the river plume; two stations (Chaara [Ch] and Canal [Ca]) are influenced by marine inflow (particularly in summer), industrial and urban effluents; and the three other stations (Menzel Abdelrahmen [MA], Menzel Jemil [MJ] and Douaouda [Do]) are located close to shellfish farms. Cell abundance of Alexandrium spp. varied among stations and months. Species of this genus showed a sporadic appearance, but they reached high concentration (0.67-7 × 10(5)cells L(-1)). Maximal cell density was detected in autumn (November 2007; station MA), at salinity of 37.5, temperature of 16 °C and NH(4)(+) level of 55.45 μM. During this month, Alexandrium spp. abundance accounted for a large fraction (61%) of the harmful phytoplankton. The statistical analysis revealed that Alexandrium concentrations were positively correlated with N:P ratio and NH4+ levels. Thus, the eutrophic waters of the lagoon favour the growth of Alexandrium, which seemed to have preference for N-nutrient loading from antrophogenic activities, as ammonium. Blooms of these potential harmful algae may constitute a potential threat in this coastal lagoon of the southern Mediterranean. Consequently, it is necessary to be well vigilant and to do regular monitoring of Alexandrium species.     

Population dynamics of potentially harmful algal blooms in Bizerte Lagoon,Tunisia

The population dynamics of potentially harmful phytoplankton in the semi-closed, coastal Bizerte Lagoon, Tunisia, in the south-western Mediterranean, were examined from November 2007 to February 2009 at six sampling stations, three situated in areas of mussel and oyster farming. The harmful species monitored included the potential producers of amnesic shellfish poisoning (Pseudo-nitzschia spp.), paralytic shellfish poisoning (Alexandrium spp.), diarrheic shellfish poisoning (Dinophysis spp. and Prorocentrum spp.), ichthyotoxins (Cochlodinium polykrikoides, Akashiwo sanguinea and Karenia mikimotoi), yessotoxins (Gonyaulax spinifera) and the discolouration of water (Neoceratium lineatum and Protoperidinium sp.). These were numerically dominated by potentially toxic species of the diatom genus Pseudo-nitzschia, which were present year-round at all stations. Prorocentrum spp., Dinophysis spp. and Neoceratium lineatum were the most abundant and recurrent harmful dinoflagellates, exhibiting their highest densities at the shellfish farming stations. Alexandrium spp. bloomed only on one occasion, reaching its highest densities at a shellfish farming station. Canonical correspondence analyses revealed significant relationships between the harmful phytoplankton species monitored and the environmental conditions. The widespread distribution of harmful phytoplankton in Bizerte Lagoon, with the permanent presence of Pseudo-nitzschia spp. and the high frequency of dinoflagellate blooms in the shellfish areas, suggests a potential risk of shellfish poisoning events in the region.     

Impact of an urban effluent on the bacterial community structure in the Arga River (Spain), with special reference to culturable gram-negative rods

The Arga River is an interesting system in which to study the impact of urban effluent pollution because it receives a single effluent in the form of wastewater discharge from the city of Pamplona. To analyze the extent of this discharge, total bacteria, culturable heterotrophic bacteria, and Gram-negative heterotrophic bacteria were enumerated and 409 isolates of the latter were identified. One sampling station was located upstream from the inflow, while five were located up to 30 km downstream. Bacterial counts increased drastically downstream from the wastewater inflow. Total bacterial numbers decreased along the 30 km downstream, the last station attaining similar values to those recorded upstream from the discharge. However, culturable heterotrophic and Gram-negative heterotrophic bacteria levels generally remained significantly higher within the 30 km zone investigated. Among the 409 isolates identified, Aeromonas spp. were the most frequent both upstream and downstream from the discharge. In contrast, although strains belonging to different genera of Enterobacteriaceae were found in all stations, their occurrence was significantly higher just downstream from the polluted discharge. Acinetobacter spp., which were never found upstream, were detected in all stations below the discharge. Our results clearly show that the bacterial community structure changes definitively downstream from the discharge and that Aeromonas were common throughout the sampling zone. Thus they cannot be considered good indicators of pollution in this setting compared to some genera of Enterobacteriaceae or some species of Acinetobacter, the distribution of which correlated better with the distance from the wastewater discharge.     

罗霄山脉种子植物区系的特有现象与残遗现象

罗霄山脉种子植物区系非常丰富, 是连接华东、华南、华中植物区系的重要通道, 区系组成具有明显的古老性和过渡性特征。本文针对该区域种子植物的特有现象和残遗现象, 分析了其组成特点及形成原因。结果表明: (1)罗霄山脉共有中国特有科3科, 特有属55属, 特有种1,624种, 罗霄山脉区域特有种43种7变种; 特有属中以古特有属为主, 并以温带成分占优势(达55.91%), 体现出明显的古老性和孑遗性。(2)罗霄山脉共有孑遗属165属, 以热带亚洲分布、东亚-北美间断分布、东亚特有及中国特有成分为主, 包括木本属132属。(3)受中新世气候波动以及第四纪冰期的影响, 许多北方热带植物群的常绿成分、北极-第三纪的落叶成分, 在罗霄山脉得以保存下来成为古特有和孑遗成分。特有现象、残遗现象的分析结果表明罗霄山脉是一个重要的生物避难所, 其对中国东部植物区系的保存和重新扩散具有重要意义。