Global chloroplast phylogeny and biogeography of bracken (Pteridium; Dennstaedtiaceae)

Bracken ferns (genus Pteridium) represent an ancient species complex with a natural worldwide distribution. Pteridium has historically been treated as comprising a single species, but recent treatments have recognized several related species. Phenotypic plasticity, geographically structured morphological variation, and geographically biased sampling have all contributed to taxonomic confusion in the genus. We sampled bracken specimens worldwide and used variable regions of the chloroplast genome to investigate phylogeography and reticulate evolution within the genus. Our results distinguish two major clades within Pteridium, a primarily northern hemisphere Laurasian/African clade, which includes all taxa currently assigned to P. aquilinum, and a primarily southern hemisphere Austral/South American clade, which includes P. esculentum and P. arachnoideum. All European accessions of P. aquilinum subsp. aquilinum appear in a monophyletic group and are nested within a clade containing the African P. aquilinum taxa (P. aquilinum subsp. capense and P. aquilinum subsp. centrali-africanum). Our results allow us to hypothesize the maternal progenitors of two allotetraploid bracken species, P. caudatum and P. semihastatum. We also discuss the biogeography of bracken in the context of the chloroplast phylogeny. Our study is one of the first to take a worldwide perspective in addressing variation in a broadly distributed species complex.     

蕨菜乙醇提取物的Ames试验研究

目的：研究蕨菜乙醇提取物的致突变作用,为蕨菜的开发利用提供一定依据;方法：制备蕨菜乙醇提取物,采用Ames试验方法,以50μg/皿敌克松作为诱变剂,分别添加提取物50、100、200、400、800μg/皿,统计回变菌落数;结果：受试物各剂量组回变菌落数均未超过自发回变菌落数的2倍,且无剂量-反应关系;结论：在本实验条件下,蕨菜乙醇提取物无致突变作用.     

Clarification of the taxonomic status and relationships of Pteridium caudatum (Dennstaedtiaceae) in Central and South America

Contemporary systematic treatments of the Central and South American bracken ferns in the genus Pteridium Gled. ex Scop. recognize morphotype caudatum as either a full species or a variety of P. aquilinum (L.) Kuhn. Geographically representative sporophytes of morphotype caudatum , including the type in the Linnaean Herbarium, are shown using spore size, guard-cell length and morphology of the cells of the false indusium to be tetraploid (based on 4 n  = 208). DNA fingerprinting of field-collected Venezuelan samples supports the generalization that morphotype caudatum is a fertile allotetraploid containing genomic elements otherwise distinctive of the southern hemisphere diploid P. arachnoideum (Kaulf.) Maxon, together with elements characteristic of northern hemisphere diploids including the North American P. aquilinum var. pubescens Underw. and P. aquilinum var. pseudocaudatum (Clute) A. Heller. Evidence of genetic isolation from taxa with overlapping distributions, as well as morphological, biochemical and ecological data, validate recognition of P. caudatum (L.) Maxon at species level. Heterogeneity observed within P. caudatum is consistent with multiple origins through independent hybridization events. Pteridium caudatum is strikingly analogous to the tropical Asian/Australasian allotetraploid P. semihastatum (N. Wallich ex J. G. Agardh) S. B. Andrews [= P. yarrabense (Domin) N. A. Wakef.].  © 2002 The Linnean Society of London . Botanical Journal of the Linnean Society , 2002, 140 , 237−248.     

Using elevated carbon dioxide to enhance copper accumulation in Pteridium revolutum, a copper-tolerant plant, under experimental conditions

In our survey in the copper (Cu) mining area of China, a sun fern (Pteridium revolutum) was found to accumulate 30-567 mg Cu kg(-1) DW (33 samples) in its fronds with a large frond biomass. Cu translocation factors in the plants varied from 0.09 to 3.88. In a greenhouse pot experiment, the effect of an elevated CO2 concentration (700 microL L(-1)) on Cu accumulation in plants was studied using three fern species (P. revolutum, Pteridium aquilinum, and Pteris vittata) grown in the Cu-contaminated soil. P. revolutum showed a higher Cu tolerance but its Cu translocation factor was lower than 1. At the elevated CO2 concentration, frond biomass of all species was significantly increased, as was the total Cu content in the fronds of P. revolutum and P. aquilinum. Our study suggests that P. revolutum could serve as a good candidate for phytoextraction of Cu-contaminated soils and that doubling the ambient CO2 concentration will facilitate its use in phytoextraction.     

响应面设计法优化蕨渣基质的灵芝培养条件

探索灵芝在以蕨渣为主要成分的固态基质中的培养条件,可为蕨渣的开发利用提供理论依据。以蕨渣为主要原料,采用响应面法对灵芝培养条件（基质蕨渣比例、基质含水量和培养温度）进行优化。结果表明,基质蕨渣比例、基质含水量和培养温度对灵芝菌丝日平均生长速率均有极显著的影响（p<0.01）,且基质含水量与培养温度之间、基质蕨渣比例与基质含水量之间存在交互作用。优化出灵芝培养条件为蕨渣比例85%,基质含水量62.5%,培养温度27℃,在此条件下,灵芝菌丝日平均生长速率为3.48mm/d。多元回归分析结果显示,基质蕨渣比例、基质含水量、培养温度与菌丝日平均生长速率之间回归模型高度显著,可用于实际生产预测。首次报道了利用蕨渣培养灵芝,为蕨渣进一步的开发研究奠定基础。     

Genetic endemism of Galapagos Pteridium

Hybridization experiments indicate that Pteridium aquilinum from Hawaii and P. aquilinum from the Galapagos Isles are intersterile. Both of these populations will cross readily with other New World collections of Pteridium. Evidence suggests that the Galapagos populations are genetically distinct from the South American populations. The genetic divergence of the Galapagos populations has not been accompanied by morphological divergence.     

蕨菜黄酮苷元的组成及含量测定研究

以80%乙醇浸提经乙醚脱脂预处理的干蕨菜粉,减压回收乙醇得浓缩液.浓缩液以8%硫酸沸水浴水解3 h后,加入20%NaOH中和至弱酸性,过滤,滤渣以三氯甲烷索氏提取获总蕨菜黄酮苷元.TLC法检测总黄酮苷元的组成,HPLC法测定其主要苷元的含量.结果表明,通过酸水解获得总蕨菜黄酮苷元,其主要成分为山奈酚,含量约占蕨菜干重的1.9%.     

广西蕨类植物孢子形态的研究Ⅲ.凤尾蕨科

利用光学显微镜和扫描电子显微镜对广西产凤尾蕨科及其近缘科蕨科、姬蕨科和碗蕨科5属9种植物的孢子形态进行了观察研究,详细描述了9种植物孢子的形态及表面纹饰特征.井栏边草、刺齿凤尾蕨、隆林凤尾蕨、剑叶凤尾蕨、林下凤尾蕨、蕨和碗蕨植物的孢子为三裂缝,辐射对称;极面观为钝三角形,赤道面观为半圆形或超半圆形;栗蕨和姬蕨植物孢子为...     

LIFE HISTORY AND HYBRIDIZATION STUDIES ON GIGARTINA STELLATA AND PETROCELIS CRUENTA (RHODOPHYTA) IN THE NORTH ATLANTIC1

Fourteen isolates of the crustose marine red alga Petrocelis cruenta J. Agardh from various localities in the British Isles, France (including the type locality), Spain and Portugal gave rise in culture to dioecious foliose plants identifiable as Gigartina stellata (Stackhouse) Batters although two isolates formed only sterile foliose blades. A total of 145 isolates of Gigartina stellata were also grown in culture from various localities in the U.S.A. (Maine), the British Isles, Iceland, Denmark, France, Spain and Portugal using both carpospores and vegetative blade apices. Two basic types of life history were found among these isolates: a direct-type life history involving the formation of further foliose plants from carpospores, some isolates of which also form spermatangia on the same papillae as the cystocarps; and a heteromorphic-type in which only crustose plants resembling Petrocelis cruenta are formed from carpospores. Only heteromorphic-type life histories were found from Spain and Portugal. Both life history types were found in plants from the U.S.A., the British Isles and northern France. Only direct-type life histories were found in plants from Iceland and Denmark. Some Petrocelis-like crusts derived from field collected G. stellata carpospores and Petrocelis crusts of hybrid progeny formed tetrasporangia in 8:16 h LD, 10° C but not in 8:16 h LD, 15° C; 16:8 h LD 10° C or 15° C; and 10:6.5:1: 6.5 h LDLD, 10° C. The spores thus formed were viable and produced normal dioecious male and female gametophytes. Short day and low temperature conditions appear necessary for tetrasporogenesis. The results from crossing experiments with 32 male and 27 female isolates of the heteromorphic-type derived from both G. stellata and P. cruenta showed that two virtually non-interbreeding populations with a high degree of geographical separation exist in the north-eastern Atlantic. Morphological differences between plants from each population are described. On the basis of culture and crossing results, Petrocelis cruenta J. Agardh is placed in synonymy with Gigartina stellata (Stackhouse in Withering) Batters.     

秦岭产9种野菜中矿质元素含量的比较

野生蔬菜是指自然生长且未经人工栽培的蔬菜,因其富含人体所需的矿质元素、氨基酸及多种维生素而备受人们青睐[1-3],被公认为天然绿色食品.近年来,随生活水平的提高,多样化的饮食结构驱使人们不断对各种食品进行开发,尤其在旅游业的发展带动下,食用野菜已成为一种时尚和保健的需要.     

A POLYPLOID SPECIES COMPLEX OF SPIROGYRA COMMUNIS (CHLOROPHYTA) OCCURRING IN NATURE 1

Investigations were conducted to determine whether ploidal changes found in laboratory cultures of Spirogyra also occur in nature. In an earlier study filament types identifiable as three different species (Spirogyra singu-laris Nordstedt, S. communis (Hassall)Kütz., S. fragilis Jao) arose from an original clonal culture through vegetative growth and sexual reproduction. These three “species” or filament groups differed in filament width, chloroplast number, zygospore size, and chromosome number. The differences in chromosome number represented a polyploid series of diploid (S. communis), triploid (S. fragilis), and tetraploid (S. singularis) forms in which width increased with ploidal level. The three width groups constituted a “species complex.” Five years after isolation of the original strain in this species complex, filaments corresponding to two of the width groups (S. singularis and S. communis) were found at the original collection site in the Santa Catalina Mountains in southern Arizona. The two field-collected groups were indistinguishable from the laboratory species complex in morphology and chromosome number. Homothallic conjugation within the two field width groups yielded progeny similar to those from homothallic conjugation of groups in the laboratory species complex. Filament widths of progeny were generally within the width limits of respective parental groups. The four possible intergroup crosses between the two laboratory and two field width groups yielded progeny similar to the wider parent (S. singularis) or the parent of intermediate width (S. fragilis). Progeny characteristics were determined by the width groups of parents, regardless of whether parents came from the laboratory or field. The similarities in morphology, chromosome numbers, and reproductive behavior of laboratory and field width groups imply that the laboratory species complex of S. communis has a natural counterpart in the field.     

Taxonomic status and relationships of bracken ferns (Pteridium: Dennstaedtiaceae) of Laurasian affinity in Central and North America

Detailed quantitative comparisons confirm and extend the discrimination of four major morphotypes amongst brackens of Laurasian affinity in Central and North America. These are recognized here at subspecies level as: Pteridium aquilinum sspp. feei , pubescens , latiusculum , and pseudocaudatum . Measurements of spore size indicate that sporophytes of P. aquilinum ssp. feei are diploid (2 n  = 104), as are sspp. pubescens , latiusculum , and pseudocaudatum . Phenetic cluster analysis based on DNA fingerprinting by arbitrarily primed polymerase chain reaction groups these four subspecies as genomically more similar to each other than to any taxa from other geographical regions. The chloroplast haplotype of ssp. feei is the same as that of sspp. latiusculum , pseudocaudatum , and pubescens with respect to the absence of both of the short direct repeats in the rps 4– trn S region (haplotype A), whereas the European ssp. aquilinum (haplotype B) has one of these repeats, and the Southern Hemisphere brackens P. arachnoideum and P. esculentum (haplotype C) have the other.  © 2008 The Linnean Society of London, Botanical Journal of the Linnean Society , 2008, 157 , 1–17.     

蕨配子体发育及卵发生的显微结构观察

运用显微观察技术对蕨(Pteridium aquilinum var. latiusculum)配子体发育和卵发生进行了研究。结果表明：(1)蕨孢子黄褐色,四面体形,具三裂缝,接种后3～7 d萌发,经丝状体和片状体阶段发育成原叶体,成熟原叶体雌雄异株或同株。(2)蕨颈卵器产生于生长点下方的表面细胞(颈卵器原始细胞),该细胞经2次分裂形成3层细胞,其上层和下层细胞发育为颈卵器壁细胞,中间细胞为初生细胞,它经2次不等分裂产生3个细胞,分别为卵细胞、腹沟细胞和颈沟细胞;刚产生时,此3个细胞紧贴颈卵器壁,细胞质内液泡较多,随着发育,卵细胞和腹沟细胞之间产生了分离腔,但二者通过孔区相连,在卵细胞上表面可观察到卵膜;此后,颈沟细胞和腹沟细胞逐渐退化,颈卵器壁细胞内具有黑色颗粒物质。连续切片观察发现,成熟卵细胞上表面中央具有受精孔。卵发生的细节尚需超微结构的研究。     

Development of microsatellite markers for the bracken fern, Pteridium aquilinum

We isolated eight novel polymorphic microsatellite loci from Pteridium aquilinum. These loci were characterized in 30 individuals, one from Bolivia, two from Peru, one from the USA, one from Japan, and 25 from Northeast China to Southwest China. The number of alleles per locus ranged from two to seven. The observed heterozygosity (H(O) ) ranged from 0.000 to 0.600 with an average of 0.3051, and the expected heterozygosity (H(E) ) ranged from 0.0966 to 0.7780 with an average of 0.4267. One locus deviated from Hardy-Weinberg equilibrium and four pairs of loci were found to be in linkage disequilibrium. These polymorphic loci will be useful in the study of the population genetic structure of Pteridium.     

Seasonal variations of diacylglyceryl-N,N,N-trimethylhomoserine content in Polypodiophyta

Diacylglyceryl-N,N,N-trimethylhomoserine (DGTS) belongs to a family of three known betaine lipids. It is synthesized by a number of bacteria, fungi, brown, red and green algae, in addition to lichens, and is also found in higher plants Bryophyta, Equisetophyta and Polydiophyta. It has been determined that DGTS plants can be DGTS-positive or DGTS-negative. The purpose of the present study was to examine the leaves of the ferns Drytopteris filix-mas (L.) Tod. and Pteridium aquilinum (L.) Kuhn, collected at different time periods during a single vegetation season for their DGTS contents. The results obtained show that amounts of DGTS in all of the species examined varies relative to the time periods in which they were collected.     

Microsporogenesis and meiotic abnormalities in the hybrid complex of Phlomis composita (Lamiaceae)

The extent of chromosome structural differences such as permanent translocations and paracentric inversions has been studied in the hybrid complex of Phlomis composita and its putative parental taxa P. lychnitis and P. crinita . They are detected as meiotic abnormalities during microsporogenesis. In total, 117 plants from 19 populations in Andalusia (southern Spain) and Levante (eastern Spain) were studied for ploidy level, chromosome clumping, multivalent or univalent formation, late bivalent disjunction with bridges, chromatin bridges and fragments, irregular polysporads and variable pollen size. All individuals had the diploid chromosome number 2 n  = 20, with no significant difference in the frequencies of the above meiotic abnormalities either at taxon or population levels. However, very different frequencies were observed on the regional scale between populations in Andalusia and Levante. The results are discussed within the theoretical framework of homoploid hybrid or recombinational speciation.  © 2003 The Linnean Society of London, Botanical Journal of the Linnean Society , 2003, 143 , 79−85.     

蕨菜黄酮分离鉴定

采用75%的乙醇提取经乙醚脱脂的蕨菜粉末,提取液回收乙醇后以石油醚、氯仿、乙酸乙酯、正丁醇依次萃取粗分段,硅胶柱层析、乙酸乙酯-甲醇系统对乙酸乙酯部位梯度洗脱,对其乙酸乙酯洗脱部分反复凝胶柱层析获得2个黄酮单体,分别鉴定为紫云英苷(1)、芦丁(2),其中化合物1为首次从蕨菜中分离得到。     

The taxonomic status and relationships of bracken ferns (Pteridium: Dennstaedtiaceae) from sub-Saharan Africa

Two morphotypes of bracken fern in the genus Pteridium Gled. ex Scop. occur in sub-Saharan Africa. The more common and widespread of these is assigned in contemporary systematic treatments to the European subspecies, P. aquilinum (L.) Kuhn ssp. aquilinum . We show that this African form is separable morphometrically and genomically from the European subspecies, and reinstate its earlier name P. aquilinum ssp. capense (Thunb.) C.Chr. The second African bracken, with a more localized tropical distribution mainly in the drainage basins of the Congo and Zambezi River systems, is confirmed as P. aquilinum ssp. centrali-africanum Hieron. ex R.E. Fr. We reject suggestions that this taxon be treated as a full species. Phenetic cluster analysis based on use of Arbitrarily Primed Polymerase Chain Reaction (A-P PCR) and Inter Simple Sequence Repeat (ISSR) fingerprinting of the nuclear genome provides evidence that the two African brackens are more closely related to each other than to other taxa, and sister to a grouping of the European sspp. aquilinum and pinetorum . The two African subspecies share solely with ssp. aquilinum a distinctive chloroplast haplotype carrying a 5-base direct repeat in the rps 4 –trn S region, confirming the close phyletic relationship between sspp. aquilinum , capense and centrali-africanum .  © 2005 The Linnean Society of London, Botanical Journal of the Linnean Society , 2005, 148 , 311–321.