贺兰山岩黄耆及其近缘种的分类学研究

依据植物野外和腊叶标本形态观察以及小叶脉序观察,对贺兰山岩黄耆(豆科)及其近缘种进行了分类学研究。结果表明:贺兰山岩黄耆及其近缘种之间较为稳定的差别体现在花器官的形态方面。贺兰山岩黄耆与短翼岩黄耆的主要区别特征是小苞片长为萼筒的1～2倍,旗瓣与龙骨瓣近等长,而后者的小苞片长为萼筒的0.5～0.8倍,旗瓣长为龙骨瓣的0.8倍。贺兰山岩黄耆与华北岩黄耆和费尔干岩黄耆的主要区别是翼瓣长为龙骨瓣的0.3～0.5倍,而后二者的翼瓣长均为龙骨瓣的0.7～0.8倍。在小叶脉序特征方面,贺兰山岩黄耆与短翼岩黄耆和华北岩黄耆近似,均为小叶一级脉纤细,二级脉不分支,二级脉环外有较多网结三级脉,具少量复合二级间脉或不明显,而费尔干岩黄耆小叶一级脉粗,二级脉多分支,二级脉环外有少量网结三级脉,具明显的简单二级间脉。此外,小叶脉序特征可能在岩黄耆属组间关系的探讨中发挥作用。     

The systematic significance of seed morphology in Sagina (Caryophyllaceae) under scanning electron microscopy

The seed morphology of 15 species ofSagina from North America, Europe, and eastern Asia was studied, utilizing the scanning electron microscope, to determine the significance of seed coat features as taxonomic characters. There is variation in particular surface features within some members of the genus. However, superficial ridges and tubercules exhibit patterns very helpful in determining relationships among some species. Two basic seed types occur in the genus and are diagnostic at the sectional level. The saginoid seed, characteristic of sectionSagina, is obliquely triangular in outline, is grooved along the two dorsal ridges, and has slightly concave lateral surfaces. The crassuloid seed, characteristic of sectionMaxima, is obliquely reniform in outline, lacks dorsal grooves, and has shallowly convex lateral surfaces.     

Ovule morphology, embryogenesis and seed development in three Hylocereus species (Cactaceae)

Pre-embryonic and embryonic stages and seed developments were studied in the diploids Hylocereus monacanthus and Hylocereus undatus and the tetraploid Hylocereus megalanthus. Ovule morphology was similar among species except for micropyle entrance. H. monacanthus had the thickest and most robust suspensor. Embryo developmental time, measured from fertilization to maturity, was significantly more prolonged in H. megalanthus. Typical to Cactaceae, the seed coat was formed by one layer of sclerenchymatous cells, but was more lignified in H. megalanthus. Morphological features common to all species included (1) cellular type endosperm with independent patterns of development in the chalazal and micropylar zones, forming a haustorium layer from the chalazal zone to the embryo; (2) an endothelial layer surrounding the embryo sac almost complete; (3) a nucellar summit growing into the micropyle; and (4) a placental obturator and a funicle connecting the ovarian tissue to the ovule. Seed development was typically endospermic (exendospermic orthodox seeds). Anomalies included two egg cells in the same embryo sac, two embryos developing in the same ovule, and embryos developing from the chalazal pole region. Total seed number and seed viability were significantly lower in H. megalanthus than in the other two taxa. Embryos at different developmental stages were observed in aborted H. megalanthus seeds.     

Mikromorphologie der Samenoberflächen der GattungEuphorbia

Seed coat surfaces of 127 species, representing 23 sections of the genusEuphorbia L. (Euphorbiaceae) have been examined with the scanning electron microscope (SEM). Various surface patterns and cell wall structures are described. In some groups the seed coat is rather uniform (e.g. in sect.Euphorbium), in other sections even closely related species can be separated by seed coat morphology (e.g.Tithymalus). The taxonomic application of testa micromorphology and the possible systematic position of certain taxa are briefly discussed. The seed coat cells of all species in sect.Tithymalus show remarkable intercellulares filled with small particles, which are described in detail for the first time.

     

落叶松种间及无性系间ISSR鉴别技术的研究

采用ISSR分子标记技术对兴安、长白和日本落叶松种间以及不同无性系进行了鉴别。从49条引物中筛选出13条ISSR引物可以对落叶松种间和无性系间进行鉴别,特异条带个体的百分率为100%,该项技术为落叶松新品种以及良种的准确鉴别提供了新的途径和手段：其中5条引物在日本落叶松、兴安落叶松和长白落叶松不同位置扩增出特异谱带,作为种的鉴定的标准,有9条引物可以对落叶松种内不同无性系分别扩增出特异片段,进行无性系的鉴别。     

Seed coat micromorphology of South American species of Hybanthus (Violaceae)

The seed‐coat of several species of Hybanthus subg. Ionidium from South America were studied by SEM (scanning electronic microscopy). Three different levels of sculpture were observed on the seed coat. The micro‐morphological patterns showed great variation between the species and should be considered as additional characters in future taxonomic treatments. The presence of a conspicuous elaiosome was observed; this structure is well known in the genus Viola and is most likely related to seed dispersal mediated by ants.     

Systematic relevance of seed coat anatomy in the European heathers (Ericeae, Ericaceae)

The anatomy of the seed coat of the European species of tribe Ericeae (Calluna, Daboecia and Erica) of the Ericaceae family was studied, and the taxonomic importance of their characters was analyzed. The seed coat is mostly formed by a one-cell layer with thick, pitted inner walls and thin outer walls that collapse at maturity over the inner walls. The cell junctions are either raised with anticlinal walls up to four times the height of the periclinal walls or are not raised with similar values for the height of both the anticlinal and periclinal walls. Three main cell junction types were found and described. The thickness of the inner walls is variable, but there is a large overlap among the results for different species. Calluna vulgaris is the only species with no pits, and E. multiflora has a pitted pattern on its inner walls, which is distinctive from the rest of the species. Our main results agree with the external seed morphology, and valuable new data were obtained for certain groups such as the E. cinerea-E. terminalis or the E. scoparia complex. The similarities that are found in seed coat characters are not in accordance with the classical taxonomic delimitation of infrageneric groups within Erica.     

Seed coat sculpture in Comanthera (Eriocaulaceae) and its implications on taxonomy and phylogenetics

Eriocaulaceae occurs primarily in the Neotropics, diversifying mostly in mountainous areas in southeastern Brazil. They are popularly known as everlasting plants, because once dried, they retain the appearance of living structures, being widely used as ornamentals. Most of the commercialized species belong to the genus Comanthera L.B.Sm., which was reestablished from Syngonanthus Ruhland. Comanthera groups 41 species, 26 in Comanthera subg. Comanthera and 15 in C. subg. Thysanocephalus, all restricted to South America. Phylogenetic analyses show Syngonanthus and Comanthera, as well as both Comanthera subgenera, as monophyletic and sister groups. Seed coat ornamentation proved to be useful and informative to help in determining taxonomic relationships in many plant groups. This study aims to characterize the external morphology of the seed coat of Comanthera and its subgenera using scanning electron microscopy, and discuss its taxonomic and phylogenetic implications. Seeds from nine species of Comanthera were analyzed, seven of which belong to C. subg. Comanthera and two to C. subg. Thysanocephalus. The results were compared with four species of Syngonanthus and one of Leiothrix. In Comanthera and Leiothrix the external periclinal walls remain intact, whereas they degenerate in the remaining genera. However, seed coat ornamentation in Leiothrix and Comanthera has distinct origins, as in the former, it comes from projections of the external layer of the outer integument, forming a striate pattern, and in the latter, from projections of the inner layer, conferring a rough pattern. Comanthera subg. Comanthera shows a rugose undulatory pattern, whilst C. subg. Thysanocephalus has a rugose micropapillate pattern. The newly reported features of the seed coat provide support for the Comanthera subgenera, thus presenting taxonomic and phylogenetic value.     

Sedum plumbizincicola X.H. Guo et S.B. Zhou ex L.H. Wu (Crassulaceae): a new species from Zhejiang Province, China

Sedum plumbizincicola X.H. Guo et S.B. Zhou ex L.H. Wu (Crassulaceae), a new species restricted to lead–zinc mining areas in Zhejiang Province, China, is described and illustrated. This taxon belongs to sect. Sedum (H. Ohba) S.H. Fu based on the adaxially gibbous carpels and follicles. It superficially resembles S. alfredii Hance and three other Sedum species found in the same area, but differs from these other taxa in bearing 4-merous flowers. Differences in geographical distribution, growth habit, phenology, macromorphology, leaf and stem anatomy, as well as seed micromorphology among S. plumbizincicola, S. alfredii and other related taxa in the genus Sedum are also reported. nrDNA internal transcribed spacers (ITS) sequences from seven populations of S. plumbizincicola support the recognition of this as a taxonomic entity distinct from S. alfredii.     

A new alkaloid from south african Conium species

Recent screening of South African Conium species for alkaloids as part of taxonomic studies has yielded γ-coniceine, coniine, methylconiine, conhydrine and a new alkaloid N-methylpseudoconhydrine. The relative stereochemistry of N-methylpseudoconhydrine was ascertained by ¹H NMR decoupling experiments. This latter alkaloid was found in significant amounts in the leaf and stem of some plants investigated and was the major alkaloid along with conhydrine in the leaf and stem of one group of high altitude plants. These plants also contained significant amounts of volatile oil, the major monoterpene being myrcene.     

Seed-specific identification of Larix gmelinii,Larix olgensis,and Larix principis-rupprechtii using sequence-characterised amplified region markers

Larix gmelinii, Larix olgensis, and Larix principis-rupprechtii are the three native and sympatric larch species in North China, and each of these species has a distinctive ecological niche. It is difficult to identify them based only on certain morphological characters, particularly the seed appearance. In this study, the seed endosperms of these three larch species were analysed using the random amplified polymorphic DNA (RAPD) technique to screen for interspecific differences. The following three RAPD markers linked to species-specific segments were observed in the different species: 1475-bp (Larix gmelinii and L. olgensis), 505-bp (Larix principis-rupprechtii), and 1121-bp (Larix gmelinii) markers. The three seed-specific fragments amplified by the RAPD markers were sequenced, and the sequences were used to design and synthesise species-specific SCAR markers. The size of the SCAR fragments was concordant with that of the RAPD species-specific fragments. Therefore, these SCAR markers can be used to identify the seeds of different larch species, thereby providing a new molecular tool for the identification of larch seeds that leads to considerable savings in terms of time and economic resources.     

中国岩黄耆属(豆科)种皮纹饰及其系统学意义

利用扫描电镜观察了国产岩黄耆属(Hedysarum L.)18个种(含3个居群)的种皮纹饰。结果表明: 岩黄耆属种皮纹饰性状在种的划分上具有重要的分类学意义。依据种皮纹饰特性, 大致分为光滑型和粗糙型2大类型以及断棱状、嚼烂状、龟纹状、网纹状与细网状5个亚型。依据其划分的类型及亚型, 种皮纹饰呈现出从断棱状、细网状到光滑状的演化趋势, 从而阐明了种皮纹饰在岩黄耆属系统演化上的重要意义。     

Physical dormancy and histological features of seeds of five Acacia species (Fabaceae) from xerophytic forests in central Argentina

Physical dormancy (impermeability of seed coats to water) is related to histological features of the seed coat. This mechanism has ecological importance since it determines the time and space of germination. The aim of the present study was to compare the histology and impermeability of the seed coat in five Neotropical Acacia species from xerophytic forests of central Argentina: Acacia aroma, A. caven, A. atramentaria, A. gilliesii and A. praecox. An imbibition experiment was performed to determine the presence or absence of physical dormancy. Seed coat structure was studied through histochemical analysis. The seeds of A. gilliesii and A. praecox were treated with ammonium ferrous sulfate to identify the sites of water entry. Acacia aroma, A. caven and A. atramentaria exhibited physical dormancy; the seed coat was very thick and compact, with a wide, sclerified parenchyma and a “water gap” for water uptake. Seed coat impermeability in these species was mainly attributed to characteristics of the lignified epidermis. By contrast, A. gilliesii and A. praecox did not have physical dormancy and showed thin seed coats with a much narrower sclerified parenchyma. Water entered the seeds of A. gilliesii and A. praecox not only through the hilar zone but also through the entire surface of the seed coat. Differences in the seed coat structure among species could be related to different regenerative responses to environmental conditions that would facilitate the coexistence of these Acacia species in the xerophytic forests of Córdoba, Argentina.     

SYSTEMATIC IMPLICATIONS OF SEED COAT MORPHOLOGY IN NAMA (HYDROPHYLLACEAE)

Seeds from 37 species of Nama (Hydrophyllaceae) were examined by scanning electron microscopy in order to assess systematic implications of seed coat structure. Generally, seed coat morphology is species specific. Nevertheless, similarities among species in seed coat organization, particularly, outer testa anatomy and wall thickening-pitting patterns allow the recognition of six groups among examined taxa; furthermore, seed coat features often suggest both intra-group and inter-group relationships. Recognized groupings do not correspond well with the more classicial treatments of Nama; rather, they suggest that a restructuring of the infrageneric and even the generic taxonomy of Nama is in order.     

Mikromorphologie der Samenschalen und Taxonomie derCactaceae: Ein raster-elektronenmikroskopischer Überblick

Micromorphology and surface sculpture of seed-coats of about 900 species ofCactaceae out of 120 genera (sensuBackeberg 1976) were examined by light and scanning electron microscopy. A survey of the seed coat characteristics (forms of testa cells, wall sculpturings, cuticular fold patterns etc.) is given. A terminology for the taxonomic application of these microstructures is proposed and their taxonomic significance is discussed.

     

Seed and trichome morphology of the Egyptian Fagonia (Zygophyllaceae) with emphasis on their systematic implications

Seed and trichome morphology of 13 taxa representing the genus Fagonia in Egypt have been studied using light (LM) and scanning electron microscopy (SEM). Macro‐ and micro‐morphological characters, including seed shape, seed size, seed coat sculpture, trichome density and structure were studied to evaluate their systematic significance. Seed shape and trichome density were found to have only minor taxonomic value, but seed coat sculpturing and trichome structure proved to be valuable characters. These characters offer evidence to combine certain species, e.g. Fagonia kassasii and F. schimperi in F. bruguieri, Fagonia microphylla in F. scabra and Fagonia thebaica in F. arabica. However, F. sinaica, F. tristis, F. boveana and F. isotricha should be maintained as separate species. Generally, the different patterns of seed and trichome morphology are useful in delimitation of species within the genus Fagonia, but they could not be used to characterize groups of related species.     

Allium aetnense (Amaryllidaceae), a new species from Sicily

A new species from Mt Etna (Sicily), Allium aetenense of A. sect. Codonoprasum, is described and illustrated. It is a diploid species (2n = 16) that grows on basaltic rocks in the mountain belt and shows close relationships with A. tenuiflorum of the Italian peninsula. Its morphology, karyology, leaf anatomy, seed coat microsculpturing, ecology and taxonomic position are examined.     

Seed Coat Microsculpturing in Brassica and Allied Genera (Subtribes Brassicinae, Raphaninae, Moricandiinae)

To obtain new information on the taxonomy of Brassica and alliedgenera, seed surfaces of 44 species (78 accessions) belongingto 11 genera of subtribes Brassicinae, Raphaninae and Moricandiinaewere examined using a scanning electron microscope. Ten typesof basic ornamentation patterns were recognized. While fourtypes were represented by only one species each, six types hadmore than one species either representing one genus (two types)or more (four types). The different species in each of the sixtypes could generally be distinguished from each other on thebasis of differences in microsculpturing features. This analysisprovides evidence for the close relationship among the variousgenera within the subtribe Brassicinae, and also the closenessof Raphanus, Enarthrocarpus and Moricandia of subtribe Raphaninaeand Moricandiinae, respectively, with the Brassicinae. Copyright2000 Annals of Botany Company Brassicinae, Moricandiinae, Raphaninae, SEM, seed coat microsculpturing, taxonomic implications