广州长洲岛植物多样性研究

通过实地调查,对广州长洲岛的植物多样性进行研究。据统计,该岛野生维管束植物共有487种,隶属于127科358属,植被主要为次生性常绿阔叶林及人工植被(果园)。对岛上野生植物的多样性和区系地理进行分析,结果表明:该岛物种集中于少数科内,科属的优势现象明显。在植物区系上,该区具有较强的热带性,但温带成分也有一定程度的入侵。最后对岛上植物多样性的保护提出建议。     

A phylogenetic analysis of subtribe Pleurothallidinae (Orchidaceae)

A cladistic analysis of subtribe, Pleurothallidinae (Orchidaceae) is based on 45 anatomical/ morphological characters. The ingroup members comprise 24 genera; the large genus Pleurothallis consists of two subgenera and ten species complexes. Three taxa representing subtribes Laeliinae and Arpophyllinae are designated as outgroup. Eight most parsimonious trees were discovered using computer assisted software (length = 230; CI = 0.27). The hypothesis that subtribe Pleurothallidinae has undergone a unilinear reduction in the number of pollinia is not supported by this study. Although the eight-pollinia state as represented by Octomeria apparently is plesiomorphic, the two-pollinia and four-pollinia states arose early in the phylogeny of the subtribe. Both two-and four-pollinia states subsequently reappeared as parallelisms. The six-pollinia state exhibited in Brachionidium is autapomorphic. This cladistic analysis suggests that Pleurothallis is not a natural genus and, perhaps may be divided into several discrete genera.     

A phylogenetic analysis of subtribe Pleurothallidinae (Orchidaceae)

A cladistic analysis of subtribe, Pleurothallidinae (Orchidaceae) is based on 45 anatomical/ morphological characters. The ingroup members comprise 24 genera; the large genus Pkurothallis consists of two subgenera and ten species complexes. Three taxa representing subtribes Laeliinae and ArpophyUinae are designated as outgroup. Eight most parsimonious trees were discovered using computer assisted software (length = 230; CI = 0.27). The hypothesis that subtribe Pleurothallidinae has undergone a unilinear reduction in the number of pollinia is not supported by this study. Although the eight-pollinia state as represented by Octomeria apparently is plesiomorphic, the two-pollinia and four-pollinia states arose early in the phytogeny of the subtribe. Both two-and four-pollinia states subsequently reappeared as parallelisms. The six-pollinia state exhibited in Brachionidium is autapomorphic. This cladistic analysis suggests that Pkurothallis is not a natural genus and, perhaps may be divided into several discrete genera.     

Allozymic variation and divergence in three species of Antirrhinum L. (Scrophulariaceae-Antirrhineae)

An allozymic study of three wild species of Antirrhinum L. A. lopesiamum Rothm., A. mollissimum Roihni. and A. microphyllum Rothm. is described. All are members of subsection Kickiella Rothm., and are narrow-range endemics of the Iberian Peninsula. The variability of the different loci, as well as the number and mobility of the alleles, differ among the three species, a demonstration of the usefulness of allozymes for the systematics of the genus. The finding of alleles unique to each species indicates high divergence among species suggesting ancient diversification, and supports the hypothesis of a geographical model of speciation. All three species show high levels of within-species variability, mainly partitioned within populations, while between populations genetic differentiation is low. Correlations between population size, sample size and genetic variability, and the usefulness of allozymic data for conservation purposes, are discussed.     

广西下雷自然保护区种子植物区系研究

依据实地调查以及馆藏标本的整理和鉴定,对下雷自然保护区种子植物区系统计分析.结果表明:(1)下雷植物种类丰富,已知维管束植物182科637属1 069种(含变种、亚种和变型),其中蕨类植物24科44属65种,裸子植物3科4属4种,被子植物150科589属1 000种.(2)居热带与亚热带过渡区,区系热带边缘性明显,热带...     

Cladistic and phenetic analysis of relationships in Vicia subgenus Vicia (Fabaceae) by morphology and isozymes

 Variation of 80 multistate morphological characters and isozymes encoded by 13 loci among 23 vetch species of the type subgenus of the genus Vicia in comparison with V. dumetorum, V. pisiformis and V. sylvatica of the subgenus Cracca is described and analyzed with cladistic parsimony and phenetic neighbour-joining methods by using two different ways of coding. Morphological analyses showed the subgenus Vicia monophyletic and revealed subgroups in a general agreement with traditionally recognized sections, except showing V. faba nested within section Narbonensis and ambiguity in the position of V. lathyroides and V. bithynica. Parsimony analysis of orthozymes as presence/absence characters revealed in the subgenus two basic monophyletic clades: 1) V. faba and three species of the section Peregrinae, V. michauxii, V. aintabensis and V. peregrina, in one subclade linked with species of the Narbonensis and Hyperchusa sections together with V. pisiformis of subgenus Cracca in a second subclade; 2) species belonging to sections Vicia, Sepium, Pseudolathyrus and Lathyroides together with V. sylvatica of the subgenus Cracca. Neighbour-joining analysis of orthozymes revealed the same two basic groups, differing only in the relative position of some species in subclusters. Both isozyme analyses showed paraphyly of the subgenera Vicia and Cracca. Parsimony analysis of orthozymes as character states of isozymes yielded a largely unresolved strict consensus cladogram of 209 most parsimonious trees, and reweighting of characters failed to produce a stable tree. Phylogenetic congruence and discordance among morphological and isozyme analyses, coding ways, homoplasy and weighting of characters are discussed. Received November 20, 2001 Accepted January 31, 2002     

Nemertean systematics and phenetic classification: an example from a group of hoplonemerteans

The applicability of numerical methods to the taxonomy of the Phylum Nemertea is assessed for a group of hoplonemertean species. The classifications obtained from various cluster and ordination methods are evaluated with reference to their predictability, i.e. the number of character or character states that can be predicted about species A knowing that it belongs to class a.     

牛背梁自然保护区种子植物多样性研究

对牛背梁自然保护区的种子植物多样性进行了研究。据统计,种子植物950种,隶属105科433属,其中,裸子植物4科8属9种,被子植物101科425属941种;木本植物372种,草本植物578种;珍稀濒危保护植物17种,资源植物丰富,分为药用,观赏,食用等10大类型,生态系统多样,按大的类型可划分为森林,灌丛,草甸,裸岩和农田,其中森林面积15055hm^2,占总面积的91.7%。是生态系统的主体。在此基础上,本文还提出了保护植物多样性应采取的对策。     

上海城市森林草本植物多样性的城乡分布格局

林下草本植物是城市森林生物多样性重要的保育层,敏感度高,可塑性强,能有效反映城市植被对城市化的响应策略。本研究在上海市范围内沿中心城区—近郊—远郊的城乡梯度,共选取16块林地共398个样方,分析了上海市森林草本群落区系特征和多样性格局沿城乡梯度的变化规律。结果表明:上海城市森林生态系统中共有草本植物144种,隶属47科118属;多年生草本74种,占半数以上(51.39%);属和种分别涵盖18和12个分布区类型和亚型,以热带和温带成分为主;外来植物28种,占比接近20%;物种丰富度和群落多样性指数均沿中心城区—近郊—远郊梯度先下降后上升,近郊最低,远郊最高;中心城区物种构成与远郊相似,与近郊差异最大。本研究揭示了城市森林生态系统中草本植物的分布格局以及多样性沿城乡梯度的变化规律,为深入开展城市化与城市植被的互作研究提供了理论支撑,为管理部门制定相关政策提供了科学依据。