Major evolutionary events in the origin and diversification of the fern genus Polystichum (Dryopteridaceae)

Recent advances in molecular systematics of the ferns make it possible to address long-standing questions about classification of the major fern genera, such as the worldwide genus Polystichum (Dryopteridaceae), comprising at least 200 species. In this study we examined rbcL sequences and morphological characters from 55 fern taxa: 34 were from Polystichum and 21 were from other genera in the Dryopteridaceae. We found that Phanerophlebia, possibly including Polystichopsis, is the sister group to Polystichum sensu lato (s.l.), including Cyrtomium. Polystichum as commonly recognized is paraphyletic. Our results lead us to suggest recognizing the clade of earliest diverging Polystichum species as a distinct genus (Cyrtomidictyum) and to continue to recognize Cyrtomium as a separate genus, leaving a monophyletic Polystichum sensu stricto (s.s.). We resolved a tropical American clade and an African clade within Polystichum s.s. However, the resemblance between the once-pinnate, bulb-bearing calciphilic species found in Asia and the West Indies appears to be the result of convergent evolution. Optimizing our morphological character transformations onto the combined phylogeny suggests that the common ancestor of Polystichum s.l. and Phanerophlebia had evolved the common features of the alliance, including ciliate petiole-base scales, once-pinnate fronds, ultimate segments with scarious tips, peltate indusia, and microscales.     

Gametophyte development and reproduction of the Asian fern Polystichum polyblepharum (Roem. ex Kunze) C. Presl (Dryopteridaceae,Polypodiopsida)

Abstract

The gametophytic generation of Polystichum polyblepharum (Dryopteridaceae), including spore germination, morphological development of the gametophytes, major vegetative features and reproduction strategies, was studied. Spore germination was of the Vittaria model and the developmental pattern was of the Aspidium model. Adult gametophytes were cordate and hairy, with unicellular hairs located at the margins and at the prothallus surface. The marginal ones were secretory. The gametophytes produced archegonia located in the central area between the notch and the rhizoids, but antheridia were never detected. Archegonia were of the normal type described for leptosporangiate ferns. Apogamous sporophytes appeared from a cellular outgrowth developed just under the apical notch. Initially, the outgrowth appeared completely surrounded by glandular hairs and scales, which persisted throughout the subsequent stages of leaf development.     

苦木化学成分研究

运用各种柱色谱和重结晶等方法对苦木Picrasma quassioides(D.Don)Benn.进行分离纯化,得到五个化合物。通过NMR等现代波谱学方法和技术鉴定化合物的结构分别为:高丽槐素-3-O-β-D-葡萄糖苷(trifolirhizin,1),高丽槐素(maackiain,2),3’,7-二羟基-4’-甲氧基异黄酮(3’,7-dihydroxy-4’-methoxyisoflavone,3),7-羟基香豆素(umbelliferone,4)和大黄素(emodin,5)。五个化合物均为首次从该属植物中分离得到。     

Dicentra scandens (D. Don) Walp. auch in der Flora Vietnams

The specimen 3064 of A. Petelot in 1927 from Chapa (Vietnam) is Dicentra scandens (D. Don) Walp. Anatomical characteristics of fruits and seeds are identically with such of the isotype, but morphological characteristics in the other parts are somewhat different.     

Antioxidant activity evaluation of essential oil and RAPD analysis of in vitro regenerated Blumea mollis (D. Don) Merr.

Essential oil obtained from the leaves of Blumea mollis (D. Don) Merr. was analyzed by gas chromatography and gas chromatography coupled with mass spectroscopy (GC and GC–MS). Bicyclic sesquiterpene, β-caryophyllene, was identified as a major compound which accounted for 24.54 %. Antioxidant activity of oil was significantly higher than that of methanol extract of callus. Murashige and Skoog (MS) medium supplemented with 4.4 μM BA showed multiple shoot induction after 8 weeks of culture. 4.6 μM Kin showed in vitro flowering and direct organogenesis was observed from the leaf explants on medium containing 4.4 μM BA and 5.4 μM NAA. Rooted plantlets developed on half strength MS medium fortified with 2.1 μM IBA were hardened and percentage survival was recorded up to 70. RAPD analysis revealed a little genetic variation in micropropagated plants.     

Inheritance of allozyme variants in bishop pine (Pinus muricuta D. Don)

Isozyme phenotypes are described for 45 structural loci and 1 modifier locus in bishop pine (Pinus muricata D. Don,) and segregation data are presented for a subset of 31 polymorphic loci from 19 enzyme systems. All polymorphic loci had alleles that segregated within single-locus Mendelian expectations, although one pair of alleles at each of three loci showed significant segregation distortion. The consistency of resolution and segregation at many loci in bishop pine makes electrophoretic analyses feasible for many purposes in this species.     

Pollination Ecology of Pedicularis megalantha D. Don (Scrophulariaceae) in the Himachal Himalaya

Abstract In the summer of 1990, the pollination ecology of Pedicularis megalantha was studied in the montane-subalpine spruce-fir forest zone (2750-3050 m) on the north slope of Mt. Huttoo at Narkanda, Himachal Pradesh, in the Indian Himalaya. Its yellow, long-tubed, nectarless flower with a curled rostrum overarched by a broad, inverted lower corolla lip was pollinated exclusively by Bombus albopleuralis and B. tunicatus workers hanging inverted from the corolla and vibrating pollen from introrse anthers concealed within the galea and releasing pollen through a small ventral opening in the galea base. The stigma, protruding from the tip of the rostrum, contacted pollen deposited on the ventral side of the insect's thorax. Corbicular pollen loads from P. megalantha pollinators indicated equal numbers of monolectic and oligolectic foragers. P. megalantha appeared to suffer from competition for pollinators by Cynoglossum wallichii at one site but to be favored in a mixed plant community with nectariferous species offering a forage resource complementary to Pedicularis pollen. As in P. punctata , the long, nectarless corolla tube of P. megalantha appears to function in extending the rostrate vibration pollination mechanism beyond the plant's foliage, which would interfere with its function. It is not an adaptation for nectar-foraging lepidopteran pollinators. P. megalantha was also found to be a root hemiparasite.     

A cytotaxonomic study of some species of Pleione D. Don (Orchidaceae)

For taxonomic purposes in the genus Pleione D. Don (Orchidaceae) breeding studies, chromosome numbers, karyotypes and analyses of pollen mother cells have been investigated. In addition to confirming many previous chromosome numbers, new tetraploid, hexaploid and triploid counts establish the existence of a tetraploid taxon (P. speciosa) , a hexaploid (P. bulbocodioides) and a triploid hybrid (P.humilis 'Frank Kingdon-Ward'). The karyotypes of the diploid species P. bulbocodioides, P.yunnanensis, P. humilis, P.forrestii and P. hookeriana are distinct, whereas those of P.formosana and P. limprichtii have similar morphology to that of P. bulbocodioides , which was also represented in the polyploid taxa. Karyotype morphology provides evidence to trace the putative parents of P. x confusa and P. humilis 'Frank Kingdon-Ward'. Results from pollen mother cells and karyotype analyses suggest that P.formosana and P. limprichtii are not cytologically differentiated from P. bulbocodiodes , and the taxa P. speciosa, P. limprichtii (tetraploid form) and P. bulbocodioides (6x) are of autopolyploid origin, being derived from the P. bulbocodioides genome. The species limits are discussed.     

三叶香茶菜的组织培养及植株再生

1植物名称三叶香茶菜[Rabdosia ternifolia（D．Don）Hara]。 2材料类别带腋芽茎段。 3培养条件（1）诱导愈伤组织的培养基：MS＋6．BA2mg.L^-1（单位下同）＋NAA0．5;（2）芽分化及继代培养基：MS＋6．BA2＋IBA0．5：（3）诱导生根培养基：1／2MS＋IBA0．5＋NAA0．1。     

Seasonal nitrogen partitioning in Japanese cedar (Cryptomeria japonica,D. Don) tissues

Plant and Soil - Plant species diversity impacts ecosystem processes, but its effects on runoff and soil erosion are not fully understood. Herbaceous vegetation control concentrated runoff and soil...     

Genetic Conservation of Insular Populations of Monterey Pine (Pinus Radiata D. Don)

Monterey pine (Pinus radiata D. Don) has only five extant native populations: three disjunct populations along the coast of California, USA and two on Mexican islands. All populations have been influenced by human activity, but the island populations in particular have been affected by introduced biota. On Guadalupe Island, the pine population has suffered drastically from overgrazing by introduced goats. We visited both island populations and described their status, took measurements, and made seed collections. We counted approximately 200 mature pine trees and virtually no seedlings on Guadalupe Island: a reduction of approximately half the population in the last 50 years. The trees are all large (mean diameter of 144 cm) –considerably larger than trees from the other four populations – and arguably near the end of their natural lifespan. The population on Cedros Island is much more robust, with thousands of trees. None sampled were as large as those on Guadalupe Island (mean diameter of 20 cm) and many groves were young and even-aged – presumably the consequence of natural regeneration after a recent fire. Tissue samples from trees on both islands did not show evidence of infection from the pitch canker pathogen, Fusarium circinatum, that has caused significant mortality in the three mainland populations. Caution is recommended in any restoration activity for the Guadalupe Island pines. Inbreeding levels could indicate the need for some planting or seeding intervention but there are also risks associated with this. Natural regeneration – after goat removal – is preferred.     

The Holocene biogeography of Pinus sabiniana Douglas ex D. Don (gray pine) in California

Pinus sabiniana Douglas ex D. Don (gray pine) is one of the dominant species in the ubiquitous Gray Pine-Blue Oak Woodland that rings the Great Central Valley of California. The species is absent, however, in a nearly 100 km section of the Sierra Nevada foothills between the Kings and Kaweah rivers. We test several previous explanations for this biogeographic gap, including prehistoric and historic anthropogenic burning, Early Holocene pluvial lakes as a migration barrier, and unique topography as a limiting factor. Through the examination of archaeobotanical and radiocarbon evidence, we find that gray pine distribution has been stable for the past 4,000 years and likely longer. Importantly, gray pine is absent in 44 of 45 individual samples from the Wahtoke Creek Site, the only archaeological site with archaeobotanical data within the modern distribution gap. This suggests that gray pine has been largely absent from the gap for over 6,000 years and refutes several previous explanations for the biogeographical gap. Instead, data support a topographical or ecological peculiarity of the gap rather than historic or prehistoric anthropogenic burning, or an Early Holocene migration of the species that was blocked by bodies of water in the Central Valley.     

Anatomical Changes Which Occur in Cuttings of Agathis australis (D. Don) Lindl 1. Wounding Responses

The basal and sub-basal regions in cuttings of Agathis australisundergo a complex series of anatomical changes. Many of theseare categorized as wound responses and include cell divisionsassociated with the cut base and the proliferation of tracheidsand phloem which arise in the interfascicular region about 4mm above the cut base. The vascular tissue arcs outwards anddownwards through the cortex. It may develop as isolated strandsonly a few cells wide or as sheets involving a number of cells.The precise pattern of vascular development appears to be determinedby its extent at the point of origin and by the presence ofobstacles such as primary and secondary resin canals which arelocated to the outside of the vascular bundles in the stem.Secondary resin canals are produced only in the rooting zonein cuttings that show extensive cell division. They arise schizogenouslyand do not form an interlinking network. Root primordia arise in the cortex at the end of isolated strandsof newly developed vascular tissue. Primordia never form inassociation with sheets of tracheids or after the convergenceof strands. In some cases virtually the entire sub-base is filledwith vascular tissue as a result of cell division and the differentiationof parenchymatous tissue. Root primordia never appear in thissituation. Agathis australis (D. Don) Lindl, kauri, cuttings, wound responses, vascular development, resin canals, root primordia, cellular differentiation     

短果杜鹃的组织培养与快速繁殖

1 植物名称 短果杜鹃(Rhododendron brachycarpum D.Don ex G.Don). 2 材料类别 新萌发嫩芽.     

Size-Structures and Reproductive Characteristics in Diploid and Triploid Populations of Disporum sessile D. Don (Liliaceae)

Abstract Disporum sessile (Liliaceae), a perennial herb of temperate forests is composed of diploid (2n=16) and triploid (2n=24) populations. The size structure differed remarkably as triploid populations had few small plants and no seedlings. Triploid flowering plants were considerably larger than diploids. Triploids that flowered were 2.5 times larger than diploids that flowered and the size of vegetative ramets produced by triploids was twice as large. In triploids, fruiting rates were quite low only with inviable seeds and vegetative propagule size was greater than that of diploids. As regards growth parameters that help to increase plant size, triploids were superior to diploids. Differences in growth and reproductive parameters between diploids and triploids may contribute to forming different patch sizes.     

Proteomic profiling of proteins associated with the rejuvenation of Sequoia sempervirens (D. Don) Endl

Background

Hepatitis B virus (HBV) is a major cause of liver infection in human. Because of the lack of an appropriate cell culture system for supporting HBV infection efficiently, the cellular and molecular mechanisms of hepadnavirus infection remain incompletely understood. Duck heptatitis B virus (DHBV) can naturally infect primary duck hepatocytes (PDHs) that provide valuable model systems for studying hepadnavirus infection in vitro. In this report, we explored global changes in cellular protein expression in DHBV infected PDHs by two-dimension gel electrophoresis (2-DE) combined with MALDI-TOF/TOF tandem mass spectrometry (MS/MS).

Results

The effects of hepadnavirus infection on hepatocytes were investigated in DHBV infected PDHs by the 2-DE analysis. Proteomic profile of PDHs infected with DHBV were analyzed at 24, 72 and 120 h post-infection by comparing with uninfected PDHs, and 75 differentially expressed protein spots were revealed by 2-DE analysis. Among the selected protein spots, 51 spots were identified corresponding to 42 proteins by MS/MS analysis; most of them were matched to orthologous proteins of Gallus gallus, Anas platyrhynchos or other avian species, including alpha-enolase, lamin A, aconitase 2, cofilin-2 and annexin A2, etc. The down-regulated expression of beta-actin and annexin A2 was confirmed by Western blot analysis, and potential roles of some differentially expressed proteins in the virus-infected cells have been discussed.

Conclusions

Differentially expressed proteins of DHBV infected PDHs revealed by 2-DE, are involved in carbohydrate metabolism, amino acid metabolism, stress responses and cytoskeleton processes etc, providing the insight to understanding of interactions between hepadnavirus and hepatocytes and molecular mechanisms of hepadnavirus pathogenesis.     

Genetic structure of Pallas pine (Pinus pallasiana D. Don) populations renewed under extreme conditions

The intensive reforestation of Pallas pine (Pinus pallasiana D. Don) in postfire sites in the native mountainous Crimean populations and at ore-mining dumps of the Krivoi Rog region around previously planted seed-producing trees has been demonstrated. Self-sown progeny that grows in the dump is characterized by better growth and arrives at the reproductive development phase earlier than that growing in a postfire forest. Allele variability at 20 allozyme loci is less in self-sown progeny than in native populations, whereas its level of heterozygosity is similar. The genetic distance (D_N) between self-sown progenies in postfire sites and ore-mining dumps is comparable to that of natural populations.