Genetic relationships and variation in the tropical mimosoid legume Desmanthus assessed by random amplified polymorphic DNA

A number of Desmanthus spp. are being evaluated for forage potential on clay soils in the tropics and subtropics and three cultivars have already been released in Australia. These accessions have been chosen from the large number of Desmanthus accessions collected from the Americas over the last 40 years. The utilization of this genetic resource is dependent on understanding the diversity within and between species. Hence 284 accessions, representing 11 species, were analysed using RAPD markers. There was considerable polymorphism in D. virgatus, D. leptophyllus and D. pernambucanus but this was not always uniform across the geographical range of these species. There was little polymorphism in D. pubescens. Few accessions of D. acuminatus, D. paspalaceus and D. tatuhyensis were represented in the collection, but these species, which have an almost sympatric distribution in Paraguay/Uruguay/Argentina/Brazil, showed affinities to D. leptophyllus and to each other. D. pernambucanus was the only species with representatives from regions other than the Americas, suggesting that this species in particular has the capacity to colonize new regions. The analysis indicated that the non-American D. pernambucanus germplasm probably originated from Brazil.     

Notes on neglected and underutilized crops Current taxonomical overview of cultivated plants in the families Umbelliferae and Labiatae

A comprehensive list is given of cultivated plants in the families Umbelliferae and Labiatae. Major uses are indicated for every species by commodity groups. Numerous neglected and underutilized crops interesting for breeding activities in the future are included in this overview as well as many lesser known possibilities of utilization.     

Patterns of rarity and taxonomic group size in plants

The objective of this research is to examine the extent to which phylogenetic and geographical drivers of rarity may interact to help us better predict distributions of rare taxa. This information is useful to conservation biologists when considering plans for the effective capture of biological diversity within reserve systems. We use 33 floras, distributed globally among five biomes, to assess pattern of rarity across taxonomic group size for plants. We show that small plant families (1-10 taxa) contain consistently fewer rare taxa than expected, while rare plants are proportionately over-represented in large plant families (>100 taxa). We also examine the distribution of species within families. The degree to which species are inequitably distributed among families varied systematically across floristic biomes. Mediterranean floras, in particular, are characterized by a greater than expected fraction of their species pool concentrated within large families, suggesting a high propensity for rarity simply by virtue of having a higher proportion of their constituent taxa within groups with a high likelihood of rarity. Finally, an analysis of a suite of floras using a common system of identifying rarity shows that the fraction of species within floras that are rare is predicted both by flora size and by a general metric (the Gini coefficient) of inequality among family sizes. Together, these patterns suggest a high degree of predictability in the distribution of rarity in plants that may reflect underlying natural speciation and extinction processes.     

VA真菌的分类鉴定

VA菌根及其真菌的分类是微生物学当前发展最活跃的领域之一.本文综述了VA真菌分类的演变、属的特性及种的鉴定方法,系统介绍了内囊霉科真菌分类的新进展、新概念及鉴定新方法.     

黑麦属基因资源研究进展

黑麦（Secale L.)是丰富小麦（triticum aestivum L.)遗传变异、选育小麦优良新品种的重要基因资源。迄今黑麦属在系统分类、细胞遗传学、分子遗传学和小麦育种中的利用等方面的研究均已取得了令人瞩目的进展。本文主要从以上四个层次，概述了黑麦属在分类、分布、核型带型分析、黑麦染色质的鉴定、重复序列研究、遗传图谱构建和利用黑麦改良小麦的育种实践等几个方面的最新进展。同时，对当前如何深入开拓和利用黑麦属基因资源进行了讨论。     

中国土壤系统分类基层单元土族建设现状与命名上存在的问题

土族与土系是土壤系统分类的基层单元,也是未来相当长时间内我国土壤系统分类工作的重点。依据国家科技基础性工作专项"我国土系调查与《中国土系志》编制(2008FY110600)"在2013年制订刊出的"中国土壤系统分类土族和土系划分标准",重点分析了1998年以来我国土壤系统分类基层单元研究工作建立的土族在命名格式上所存在的问题,旨在为今后我国的土族建设工作提供参考。     

丛枝菌根真菌的生物多样性研究进展

由于进化历程和生存条件的差异,丛枝菌根(AM)真菌的发生、分布和功能都具有多样性特点。本文简述了近年来AM真菌在系统分类,种的多样性和功能多样性方面的研究成果,分析了当前研究中所存在的问题和动向。     

Determining genetic diversity between lines of <Emphasis Type="Italic">Vigna unguiculata</Emphasis> subspecies by AFLP and SSR markers

AFLP (Amplified Fragment Length Polymorphisms) and SSR (Simple Sequence Repeat) markers were utilized to assess genetic diversity and relatedness between Vigna unguiculata subspecies. Three AFLP primer combinations and 10 SSR primer sets successfully identified closely related accessions, and the presence of heterogeneity in some accessions. AFLP methodology was successful in separating different species of Vigna. However, the level of intra-subspecies variation was as great as was the interspecies variation with both marker methods. The number of markers employed was insufficient to successfully group the subspecies into distinct clades.     

Identifying earthworms through DNA barcodes

With almost 3000 species, earthworms provide important model systems for studying soil fauna. However, species identification of earthworms is difficult and therefore limiting. The use of DNA barcodes, which are short sequences from standardized regions of the genome, has been regarded as a promising approach to resolve this taxonomic dilemma. We evaluated sequence diversity in the mitochondrial cytochrome-c oxidase I (COI) gene as a tool for resolving differences among species of Chinese earthworms. Members of six genera and 28 species were examined, and species were successfully discriminated in all cases. Sequence divergence within species was generally less than 1%, whereas divergence between species was greater than 15% in all cases. Divergence among individuals of Eisenia fetida were much higher (up to 7.8%); however, this may represent the presence of unrecognized sibling species or subspecies. We conclude that although it cannot completely replace taxonomy, the DNA barcode is a powerful tool for identifying species of earthworms and provides a useful complement to traditional morphological taxonomy.     

棕黑锦蛇染色体核型和Ag-NORs研究

初步研究了吉林长白山地区的棕黑锦蛇染色体核型及Ag-NORs特征,并与已经报道的安徽产赤峰锦蛇有关特征进行对比。结果表明,吉林长白山地区的棕黑锦蛇染色体2n=36,由8对大型染色体和10对微小染色体组成,可分为A、B和C3组,性染色体属于ZZ/ZW型,Ag-NORs也都位于1对微小染色体上。棕黑锦蛇仅在第8对和W染色体的相对长度和臂比值上与赤峰锦蛇有差异,染色体其他特征,包括数目、形态、染色体类型等,在2蛇之间基本一致。锦蛇属染色体属名变化较大,但多数种类2n=36。棕黑锦蛇和赤峰锦蛇染色体数目相同,且仅在第8对和W染色体上有差异,由于核型存在地理多态性,单纯依据上述差异尚不能为这2种蛇的分类提供充足的证据。今后,除继续对不同地理分布的棕黑锦蛇和赤峰锦蛇的染色体进行研究外,对棕黑锦蛇和赤峰锦蛇的分类问题还需要从整合分类学角度进行深入研究。