9,263 research outputs found

    Transplanting the leafy liverwort Herbertus hutchinsiae : A suitable conservation tool to maintain oceanic-montane liverwort-rich heath?

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    Thanks to the relevant landowners and managers for permission to carry out the experiments, Chris Preston for helping to obtain the liverwort distribution records and the distribution map, Gordon Rothero and Dave Horsfield for advice on choosing experimental sites and Alex Douglas for statistical advice. Juliane Geyer’s help with fieldwork was greatly appreciated. This study was made possible by a NERC PhD studentship and financial support from the Royal Botanic Garden Edinburgh and Scottish Natural Heritage.Peer reviewedPostprin

    Structure determination of a 4-pyrone from the liverwort <i>Plagiochila bifaria</i> (Sw.) Lindenb. (Plagiochilaceae)

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    The centenary of the presentation in 1907 of the "polyketide" hypothesis by Collie, along with his use of a 4-pyrone as an example, is marked by reporting the discovery and isolation of 2-(3,4-dimethoxyphenethyl)-6-methyl-4-pyrone from &lt;i&gt;Plagiochila bifaria&lt;/i&gt;. This compound dominates the phytochemical profile of the deuteriochloroform extract of a Venezuelan specimen of &lt;i&gt;P. bifaria&lt;/i&gt; and the structure was determined using spectroscopic techniques, especially 2D NMR. This natural product is novel because it contains what appears to be the first example of a monocyclic 4-pyrone that has a polyketide origin. The hypothetical pathway for cyclization of a triketocarboxylic acid to a 4-pyrone was known to be applicable to model systems but no examples of natural products from this route were known. This compound is the same as one of a series of compounds observed previously in an extract of a Brazilian specimen of &lt;i&gt;P. bifaria&lt;/i&gt;; the working structures that were proposed earlier require revision. The mass spectral characteristics are the same as those reported (parent and base peak) in 1987 for the major component observed in the GC-MS profile of an extract of a specimen of &lt;i&gt;P. bifaria&lt;/i&gt; from Peru. The roles played by Birch and Robinson in the renaissance of the polyketide hypothesis almost fifty years after its initial launch are considered. Based on evidence from their publications, they worked independently of each other. It appears Robinson always had knowledge of Collie's hypothesis when developing ideas about structural relations of natural products whereas Birch initially was unaware of both Collie's and Robinson's ideas on the subject

    Widespread association between the ericoid mycorrhizal fungus Rhizoscyphus ericae and a leafy liverwort in the maritime and sub-Antarctic

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    A recent study identified a fungal isolate from the Antarctic leafy liverwort Cephaloziella varians as the ericoid mycorrhizal associate Rhizoscyphus ericae. However, nothing is known about the wider Antarctic distribution of R. ericae in C. varians, and inoculation experiments confirming the ability of the fungus to form coils in the liverwort are lacking. Using direct isolation and baiting with Vaccinium macrocarpon seedlings, fungi were isolated from C. varians sampled from eight sites across a 1875-km transect through sub- and maritime Antarctica. The ability of an isolate to form coils in aseptically grown C. varians was also tested. Fungi with 98–99% sequence identity to R. ericae internal transcribed spacer (ITS) region and partial large subunit ribosomal (r)DNA sequences were frequently isolated from C. varians at all sites sampled. The EF4/Fung5 primer set did not amplify small subunit rDNA from three of five R. ericae isolates, probably accounting for the reported absence of the fungus from C. varians in a previous study. Rhizoscyphus ericae was found to colonize aseptically-grown C. varians intracellularly, forming hyphal coils. This study shows that the association between R. ericae and C. varians is apparently widespread in Antarctica, and confirms that R. ericae is at least in part responsible for the formation of the coils observed in rhizoids of field-collected C. varians

    Two new Lejeuneaceae records for the Colombian liverwort flora

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    Two epiphyllous Lejeuneaceae, Cololejeunea surinamensis and Drepanolejeunea polyrhiza, previously known from Amazonian Brazil, are recorded for the first time in Colombia. They were found as epiphylls on understory shrubs in the middle Caquetá area in Colombian Amazonia. Cololejeunea surinamensis was found in the Tierra Firme forests and D. polyrhiza was found in the floodplains of the Caquetá River.Dos especies de Lejeuneaceae epífilas, Cololejeunea surinamensis y Drepanolejeunea polyrhiza, previamente conocidas de los bosques amazónicos de Brasil son reportadas por primera vez para Colombia. Las especies fueron encontradas como epífilas sobre hojas de arbustos del sotobosque en el área del medio Caquetá en la amazonía Colombiana. Cololejeunea surinamensis fue encontrada en los bosques de tierra firme, mientras que D. polyrhiza fue encontrada en los planos inundables del Río Caquetá

    Bryophytes and their distribution in the Blue Mountains region of New South Wales

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    The bryophytes (mosses, liverworts and hornworts) that occur in the Blue Mountains region of New South Wales (latitude 33˚–34˚ S, longitude 151˚–151˚40’ E) are listed and information is provided on their distribution in the region. Species lists are based on herbarium specimens and field collections. 348 bryophyte taxa have been recorded from 70 families, including 225 moss taxa (in 108 genera from 45 families), 120 liverwort taxa (in 51 genera from 24 families) and 3 hornwort taxa (in 3 genera from one family). The moss families with most taxa are the Pottiaceae (with 23 taxa in 13 genera), Bryaceae (with 15 taxa in 3 genera) and Fissidentaceae (with 13 taxa). The largest genera are Fissidens (13 taxa), Campylopus (9) and Macromitrium (8). The liverwort family with the most taxa is Lepidoziaceae, with 29 taxa in 10 genera. The largest liverwort genera are Frullania (11 taxa) and Riccardia (8). The species lists include collections from both bushland and urban areas. Natural features of the Blue Mountains, including topography, altitude, climate and vegetation appear to be important factors influencing the number of bryophyte species recorded from each location. The number of collections from particular locations has been considerably influenced by ease of access, particularly proximity to roads, public transport and railway stations. The species lists include many records from areas that were not accessible to the early collectors of the late 19th and early 20th centuries such as Wollemi National Park, Gardens of Stone National Park, Newnes Plateau and Kanangra-Boyd National Park

    Molecular, morphological, and phytochemical evidence for a broad species concept of Plagiochila bifaria (Hepaticae)

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    Debate over the synonymy of the European Plagiochila killarniensis and the Neotropical P bifaria of R sect. Arrectae has focused on differences in secondary metabolite composition. The broad morphological species concept of R bifaria proposed in recent papers has now been tested by comparing nrDNA ITS1 and ITS2 sequences of R bifaria populations encompassing several different morpho- and chemotypes from the British Isles, Tenerife, Costa Rica, Brazil, Ecuador, and Bolivia, with sequences of other species of R sects. Arrectae, Rutilantes, and Fuscoluteae. Phylogenetic analyses demonstrate that specimens of P. bifaria form a well supported clade within Plagiochila sect. Arrectae. Sequences of R bifaria from the British Isles, Tenerife, and Ecuador, representing the "methyl everninate" chemotype, form a well supported subclade within the P bifaria clade. Sequences of specimens from Costa Rica, Brazil, and Bolivia are placed in the basal part of the R bifaria clade. The data support a broad species concept of P bifaria. The different chemotypes do not warrant distinct taxonomic ranks. Plagiochila centrifuga and P. compressula are treated as new synonyms of R bifaria

    90Sr uptake in the freshwater liverwort Riccia fluitans L.

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    90Sr is a radioactive isotope of strontium produced by nuclear fission, with a half-life of 28.8 years. This artificial radioisotope is present in natural ecosystems as the results of radioactive fallout from nuclear weapons or releases during nuclear power plants accidents; because of its similarity with Ca*2 is quickly incorporated into the biota. The high mobility of Sr+2 in aquatic compared with terrestrial ecosystems makes the uptake and accumulation of 90Sr+2 higher in aquatic than in terrestrial plants. Here we analyse the uptake rate, kinetics and retention, concentration factor (CF) of 90Sr in the freshwater liverwort Riccia fluiants. 90Sr uptake by R. fluitnas shows a bi-phasic kinetics that fits the Michaelis & Menten model in both micro and milimolar concentration ranges. Apparent semi-saturation constants (KM) were 15 µM and 2 mM for the high and low affinity ranges, respectively. The presence of the K+ channels blocker tetraethyamonium (10 mM TEA) inhibits 90Sr uptake by a 25%. However, the presence of 1 mM La+3 completely inhibits 90Sr uptake in this plant. Maximum incorporation rate occurs at alkaline external pH (8.3), either in plants grown in the presence of K+ or in the absence. Finally, gradual increases of the Ca2+ concentration in the medium progressively inhibits 90Sr uptake. CF values are higher in K+ -deficient plants, CF maximum of 1500, than in K+ -sufficient, (maximum CF of 600) and show similar responses to inhibitors, pH or Ca2+. CF values progressively decrease at increasing external Ca2+ concentrations, higher CF values are found at pH 8.3 but lower values are observed in the presence of TEA, being close to zero in the presence of La+3. The different 90Sr uptake rates in K+-sufficient and K+-deficient plants and TEA sensitivity indicate that one part of 90Sr would be transported through non-selective cation channels. Furthermore, Ca2+ and La3+ sensitivities suggest that 90Sr could be incorporated through Ca2+ channels.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech. Spanish MINECO: BFU2017-85117-R and BIO2016-81957-RED

    British Bryological Society expedition to Mulanje Mountain, Malawi : 13., new and other unpublished records

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    Further results are provided of the 1991 British Bryological Society Expedition to Mulanje Mt., Malawi including 168 taxa of bryophyte, comprising 72 taxa of liverwort (38 new to Malawi) and 96 taxa of mosses (45 new to Malawi)

    Bryophyte diversity patterns in flooded and tierra firme forests in the Araracuara Region, Colombian Amazonia

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    We investigated patterns of bryophyte species richness and composition in two forest types of Colombian Amazonia, non-flooded tierra firme forest and floodplain forest of the Caquetá River. A total of 109 bryophyte species were recorded from 14 0.2 ha plots. Bryophyte life forms and habitats were analyzed, including the canopy and epiphylls. Bryophyte species did not show significant differences between landscapes but mosses and liverworts were different and with opposite responses balancing the overall richness. Independence test showed differences in both life form and habitat use distribution between the two forest types with more fan and mat bryophytes species in the floodplains, and more epiphytic liverworts in the tierra firme forest. Correspondence analysis showed differences in the bryophyte species assemblage between the two forest types where they may be responding to the higher humidity provided by the flooding. Despite of, the environmental differences detected, epiphyll species assemblages were not strongly affected. Apparently, epiphyll habitat is stressful enough to hide the environmental differences between the flooded and Tierra firme forests.Investigamos los patrones de riqueza de especies y composición florística de briofitos en dos tipos de bosque en la Amazonía Colombiana. Bosques no inundados de Tierra firme y bosques periódicamente inundados en los planos inundables del Rió Caquetá. Encontramos 109 especies de briofitos en 14 parcelas de 0.2 ha. Nosotros analizamos diferencias en la distribución de formas de vida y hábitat de los briofitos entre los dos tipos de bosque incluyendo especies del dosel y epifilas. El número de especies de briofitos no mostró diferencias significativas entre los dos tipos de bosque. Pero musgos y hepáticas si tuvieron diferencias con respuestas opuestas balanceando el número total de especies. Pruebas de independencia mostraron diferencias en la distribución de formas de vida y uso de hábitat entre los dos tipos de bosque con más especies de abanicos y esteras en los planos inundables, y más especies de hepáticas epifitas en el bosque de Tierra firme. El análisis de correspondencia mostró diferencias en la composición florística de briofitos entre ambos tipos de bosque, donde las comunidades de briofitos pueden estar respondiendo a un gradiente de humedad aportada por la inundación periódica de los planos inundables. La composición florística de los briofitos epifilos no mostró una separación tan clara entre los tipos de bosque como si fue detectada en los otros hábitat donde los briofitos fueron encontrados. Aparentemente, el hábitat epifilo es suficientemente estresante para ocultar el efecto de las diferentes condiciones ambientales de los bosques inundables y de Tierra firme

    On the occurrence of bryophytes and macrolichens in different lowland rain forest types at Mabura Hill, Guyana

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    A floristic and ecological study of bryophytes and macrolichens in different lowland rain forest types around Mabura Hill, Guyana, South America, yielded 170 species: 52 mosses, 82 liverworts and 36 macrolichens. Lejeuneaceae account for about 30% of the species and are the dominant cryptogamic family of the lowland rain forest. Special attention was paid to the flora of the forest canopy, by using mountaineering techniques. It appeared that 50% of the bryophyte species and 86% of the macrolichens occurred exclusively in the canopy. Dry evergreen 'walaba' forest on white sand is particularly rich in lichens whereas the more humid 'mixed' forest on loamy soil is characterized by a rather rich liverwort flora. More species are exclusive to the mixed forest than to dry evergreen forest due to the 'canopy effect', i.e. the occurrence of xerophytic species in the outer canopy of both dry and humid forests. Furthermore, canopy species have wider vertical distributions on trees in the dry evergreen forest than in the mixed forest, due to the more open canopy foliage of the dry evergreen forest
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