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B. Sorkin 《Historical Biology》2013,25(4):375-388
Giant bear-dogs of the genera Amphicyon and Ischyrocyon (Carnivora, Amphicyonidae, Amphicyoninae) were the largest carnivorans in North America during middle and late Miocene (17.5–8.8 Mya) with a dental and skeletal morphology that combined features found in living Ursidae, Canidae, and Felidae. This study tests previously proposed models of diet and hunting behaviour of these extinct carnivorans. Relative grinding area (RGA) of lower molars and wear pattern on upper molars suggest that bear-dogs were carnivorous. Amphicyon and Ischyrocyon possessed skeletal features of both ambush (short distal limb segments) and pursuit (caudally bent olecranon process of ulna) living predators. Therefore, bear-dogs probably pursued their prey (mediportal ungulates) for a longer distance but at a slower speed than do living ambush predators. Upon catching up to its prey a bear-dog probably seized it with powerfully muscled forelimbs and killed it by tearing into its ribcage or neck with canines set in a narrow rostrum. 相似文献
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Abstract Five populations belonging to three subspecies of Dianthus rupicola Biv. (D. rupicola subsp. rupicola, D. rupicola subsp. aeolicus, and D. rupicola subsp. lopadusanus) and growing in different geographical areas of Sicily were tested for seed germination at various temperatures. All populations showed high germination rates with an optimum temperature between 15°C and 25°C. Efficient seed germination might contribute significantly to the preservation of these subspecies which are currently exposed to several environmental threats. 相似文献
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Abstract The terrestrial orchid, Orchis pauciflora Ten., growing in poor grassland and garrigue of Central Mediterranean region, is local and rare and has been included in the red lists of several Italian regions. We investigated the diversity of fungal associates in O. pauciflora adult plants collected in two protected areas of Tuscany (Central Italy). Genomic DNA was extracted from mycorrhizal roots of 12 orchid plants and the fungal ITS were amplified and sequenced. Several fungal associates, belonging to different taxa of basidiomycetes (Tulasnellaceae) and ascomycetes such as Leptodontidium, Exophiala and Phialophora species, were recovered. The trophic role of these fungi and their impact on O. pauciflora growth and conservation are discussed. 相似文献
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An original protocol of micropropagation of Aristolochia rotunda L., an important herb for the survival of an endangered butterfly was developed. The cytokinin 6-benzylaminopurine affected the production of new shoots but had no effect on shoot length. The addition of indole-3-butyric acid (IBA) had a negative effect on shoot length. Best results in terms of rooting percentage and root length were achieved with 1.5 μM IBA. The protocol can be employed to enhance the number of A. rotunda in the environment. 相似文献
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G. Sicoli F. Trové A. M. Palermo F. Carruggio G. Pellegrino L. Forte 《Plant biosystems》2018,152(4):684-693
A rust fungus attack was observed on Tree Spurge (Euphorbia dendroides) in two regions of southern Italy. Uredinia and telia of a Melampsora species were detected on the leaves, bracts of the cyathia and capsules of E. dendroides. On the basis of the morphological characteristics and rDNA ITS sequences of the above mentioned structures, the fungus was identified as M. gelmii. This report suggests that M. gelmii seems to be a specific taxon in the M. euphorbiae complex and to be more widespread than previously detected in Italy. Further investigations within the M. euphorbiae complex would be desirable in order to elucidate the identity of M. gelmii as a peculiar form of a still poorly explored species. 相似文献
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G. Bacchetta A. Cao G. Cappai A. Carucci M. Casti M. L. Fercia 《Plant biosystems》2013,147(4):1054-1063
Abstract A two-year study has been conducted in an abandoned Pb/Zn mining site, with the aim of investigating the feasibility of phytoremediation using two native Mediterranean plants (Pistacia lentiscus and Scrophularia bicolor) and of assessing the performance of amendments able to reduce the toxic effects of heavy metals. The amendments used were compost, chemical fertilizer, and zeolites, used singly or in combination. Depending on the amendments applied, the two species showed different mortality rates in the different plots, but all produced an increase in P. lentiscus survival, while S. bicolor survival improved only when amended with zeolite or zeolite + fertilizer. Scrophularia bicolor proved to be a more efficient accumulator than P. lentiscus, especially for Pb uptake. Pistacia lentiscus accumulated metals mostly in the roots. The effect of amendments was to generally reduce the bioavailable metal fraction, especially lead, in the plots amended with compost. Pistacia lentiscus proved to be the most suitable species for phytostabilization and environmental restoration, both for its resistance to metals and high phytomass production. The experiments demonstrate that the use of compost not only encourages this kind of revegetation in degraded areas, but is also an economical option that uses a by-product of solid municipal waste treatment. 相似文献
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Abstract The first unambiguous documentation of hybridism in the genus Doronicum (Senecioneae – Asteraceae) is reported. All our morphological, karyological and molecular data concur to indicate that Doronicum × minutilloi Peruzzi hybr. nov. (2n = 60) is a hybrid growing in Monti Aurunci (Central Italy), originated from the spontaneous crossing D. orientale Hoffm. (2n = 60) × D. columnae Ten. (2n = 60). This new hybrid shows a slightly higher morphological, karyotypic and ribotypic affinity with D. columnae, but shares a trnL-trnF IGS haplotype with D. orientale, and co-occurs with the latter species only; it has reduced fertility and a high potential for vegetative propagation through rhizome fragmentation. Our results led us to suspect in fieri homoploid hybrid speciation. 相似文献
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Abstract To analyze biomass and nutrient dynamics of Mediterranean seasonal dimorphic shrubs, aboveground biomass (AGB) and belowground biomass (BGB), litterfall (LF), aboveground net annual primary production (ANPP), and nutrient allocation and turnover were estimated in Cistus salviifolius and C. ladanifer, during two years, in southern Portugal. AGB, BGB, LF, and ANPP of C. salviifolius are within the range reported for other seasonal dimorphic plants, while those of C. ladanifer are closer to evergreen sclerophylls. Leaf renewal was higher for C. salviifolius than for C. ladanifer, especially for winter leaves, while root-to-shoot ratio and accumulation of live wood was greater in the latter. The concentrations of N, K, Ca, and Mg were lower in leaves of C. ladanifer than in those of C. salviifolius, suggesting less nutritive requirements for the former. Moreover, leaf nutrient translocation was higher in C. ladanifer than in C. salviifolius. Therefore, C. ladanifer shrubs seem to be more efficient with respect to carbon uptake, even during severe drought, while those of C. salviifolius act as weaker sinks more susceptible to the negative effects of drought. Additionally, C. ladanifer seems to have a competitive advantage in more arid conditions, as a great proportion of its annual nutrient requirement may derive from internal sources. 相似文献
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Jih-Pai Lin Samuel M. Gon III James G. Gehling Loren E. Babcock Yuan-Long Zhao Xing-Liang Zhang 《Historical Biology》2013,25(1):33-45
Constraining the origin of animal groups is allowed, to some extent, by discoveries of Cambrian Lagerstätten that preserve both mineralizing and nonmineralizing organisms. A new species is reported here of the Cambrian arthropod Skania, which bears an exoskeleton that shares homologies with the Neoproterozoic (Ediacaran) organism Parvancorina and firmly establishes a Precambrian root for arthropods. A new monophyletic group, Parvancorinomorpha, is proposed as the first clade within the arthropod crown group demonstrably ranging across the Neoproterozoic–Paleozoic transition. The Parvancorinomorpha is interpreted to be the sister group of the Arachnomorpha. Incipient cephalization in Skania and related genera represents a step in the progression toward division of a cephalon from a large posterior trunk as shown in Cambrian arachnomorphs such as naraoiids and the addition of a pygidium and thoracic tergites as shown in the arachnomorph clade basal to trilobites. This evidence can serve as a new calibration point for estimating the divergence time for the last common ancestor of arthropods and priapulids based on molecular clock methods. 相似文献
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In this study, we describe intraspecies variation in the αC connector region of the bovine fibrinogen Aα gene. Sequencing and genotyping of six bovine breeds revealed 7 to 10 tandem repeats in the αC connector region. In addition, we observed length differences between B. indicus and B. taurus, with the B. indicus having longer fibrinogen αC connectors (10-repeat alleles) than B. taurus (7- and 9-repeats). The difference in tandem repeats may be related to the function of blood coagulation system. 相似文献
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Sezione Venta 《Plant biosystems》2013,147(3):664-686
Abstract Totally, 26 xerohalophytic species belonging to the associations Cakilo-Xanthietum italici and Echinophoro-Elymetum farcti were registered at the Velika pla?a beach (Montenegro); they were distributed following the spatial succession common in this type of habitat. Three transects of different terrain morphology (positioned perpendicularly to the shoreline) were surveyed to establish if there were any differences in the floristic composition and species distribution due to the configuration discrepancy. Moreover, each transect was divided into zones: The first zone from 0 to 30 m inland, the second zone from 30 m to 60 m inland, and the third zone from 60 m to the end of beach (75–115 m, depending on transect length). The floristic composition was relatively uniform in the different transects. However, the number of individuals per species differed significantly among these transects. An analysis of the qualitative composition of transects/zones showed high differences between zones within transects I and II, whereas species composition of zones within transect III was mostly similar. When analyzing the quantitative composition of species, a positive correlation between the distance from the shoreline and the number of individuals per species in transects I and II was registered for most analyzed species (Spearman correlation, p < 0.001). This indicates that terrain configuration affected the ability of present species to become established and propagate. 相似文献
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Impatiens L. is taxonomically a complicated genus that necessitates fresh characterization to resolve its taxonomy. This study therefore aimed at ascertaining micro-morphological characters in the foliar epidermis of Impatiens. For this purpose, we gathered twelve taxa (10 species and 2 subspecies) mostly from the northern regions of Pakistan and studied qualitative and quantitative characters depicting variation in epidermal cells, stomata, and trichomes on both surfaces. Multicellular, uniseriate trichomes were observed only in I. balsamina L., and raphides in I. balfourii Hook. f. and I. thomsonii Hook. f. while stomata were exclusively anomocytic in all species. Morphological variation in the foliar epidermal characters and their diagnostic value has been depicted by constructing a taxonomic key to all taxa. The study revealed that although foliar epidermal characters in Impatiens did not desirably assort taxa on the basis of structural topographies, yet demonstrated adequate variation distinguishing the Pakistani taxa. 相似文献
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Dr Bjarne Styrishave Berit H. Bojsen Hanne Witthøfft Ole Andersen 《Marine and Freshwater Behaviour and Physiology》2013,45(1):63-77
Heart rate, locomotor activity, and oxygen consumption were recorded simultaneously and continuously in seven individuals of the noble crayfish Astacus astacus (Linneus 1758) and seven individuals of the signal crayfish Pacifastacus leniusculus (Dana 1852). The recordings were made in the laboratory over 7 days at 15°C under a 12?:?12?h dark?:?light regime. Circadian rhythms in heart rate, locomotor activity and oxygen consumption were found both in A. astacus and P. leniusculus. Increased heart rate, locomotor activity, and oxygen consumption levels during night time in both A. astacus and P. leniusculus illustrated expression of nocturnal behaviour. No differences in oxygen consumption levels were observed between A. astacus and P. leniusculus. Also, no significant difference between heart rate levels or heart rate variances was found in A. astacus and P. leniusculus at night. During day, however, heart rate levels, heart rate variances and locomotor activity were higher in P. leniusculus than in A. astacus. The higher activity level in P. leniusculus than in A. astacus during daytime indicates that P. leniusculus is less strictly nocturnal than is A. astacus. 相似文献
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The effects of light on the metabolic rates of the hypogean amphipod Niphargus stygius and the epigean amphipod Gammarus fossarum were compared by measuring oxygen consumption and respiratory electron transport system (ETS) activity. They were exposed to light intensities of 720 and 4700?lx at 10°C. Oxygen consumption increased significantly in N. stygius exposed to both low and high intensities of light, but no significant increase was observed in G. fossarum at either intensity. The increase of oxygen consumption in N. stygius was significantly greater at the higher light intensity. This indicates a stress response in which exploitation of half the metabolic potential for energy production in N. stygius during exposure to high light intensity constitutes an adverse effect on its metabolism, since this species usually uses less than 25% of its total metabolic potential for standard metabolic demands. 相似文献
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A new Centaurea L. (Asteraceae) species from Turkey is described and illustrated. Centaurea mersinensis Uysal and Hamzao?lu exists on calcareous slopes in Pinus brutia forests of Ayd?nc?k (Mersin) in southern Anatolia. It belongs to C. sect. Phalolepis (Cass.) DC., and taxonomically its closest relative is C. lycaonica. Diagnostic morphological characters from very similar taxa are provided, and a key is provided that includes related species of sect. Phalolepis from Turkey. The geographical distribution of the new species and relatives of the same section are mapped. The chromosome number of C. mersinensis, 2n = 18, counted in root tips, is also reported and illustrated. 相似文献
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Yu Zou Wenzhong Hu Aili Jiang Mixia Tian 《Preparative biochemistry & biotechnology》2013,43(6):605-615
Histidine decarboxylase (HDC) from Enterobacter aerogenes DL-1 was purified in a three-step procedure involving ammonium sulfate precipitation, Sephadex G-100, and DEAE-Sepharose column chromatography. The partially purified enzyme showed a single protein band of 52.4 kD on sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). The optimum pH for HDC activity was 6.5, and the enzyme was stable between pH 4 and 8. Enterobacter aerogenes HDC had optimal activity at 40°C and retained most of its activity between 4 and 50°C. HDC activity was reduced in the presence of numerous tested compounds. Particularly with SDS, it significantly (p < 0.01) inhibited enzyme activity. Conversely, Ca2+ and Mn2+ showed prominent activation effects (p < 0.01) with activity increasing to 117.20% and 123.42%, respectively. The Lineweaver–Burk plot showed that K m and V max values of the enzyme for L-histidine were 0.21 mM and 71.39 µmol/min, respectively. In comparison with most HDCs from other microorganisms and animals, HDC from E. aerogenes DL-1 displayed higher affinity and greater reaction velocity toward L-histidine. 相似文献
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Juniperus navicularis is an endemic taxon of Iberian Peninsula that develops on paleodunes of coastal ecosystems and whose distribution range is not well defined. In this paper, we present the results of the morphological analysis in populations attributed to J. navicularis of southern Spain. In order to assess the similarity between Portuguese and Spanish populations, the Mann–Whitney U test was performed, the same test was also applied between this taxon and Juniperus oxycedrus subsp. oxycedrus. In order to distinguish this species from other taxa of the Juniperus oxycedrus group (subsp. oxycedrus, subsp. badia, subsp. macrocarpa) in the southwestern Mediterranean region, a principal component analysis has been carried out. New data about the chorology and ecology of Spanish populations considered as a priority habitat in the Habitat Directive as well as number of individuals and conservation status are provided. 相似文献
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The present work is aimed at studying several Asperula (Rubiaceae) sect. Cynanchicae populations in southern Apennines, Italy, with particular reference to those referred to A. calabra, by employing biometrical methods on macromorphological data. Among other historical misapplications, A. cynanchica subsp. cynanchica seems to be very rare or missing in southern Italy. The enigmatic Asperula calabra, confirmed to be limited to a single mountain population in Calabria, appears to be strictly related to A. aristata subsp. scabra, so we suggest to treat it as a further subspecies of A. aristata. This latter species is otherwise distributed throughout southern Italy with subsp. scabra and subsp. aristata, characterised by slight morphological differences, which are correlated to altitudinal ranges. 相似文献
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A new desmid genus, Actinodontum Alfinito et Coesel, is described from mountain areas of tropical Africa. The newly described genus differs from the allied genus Actinotaenium by the presence of marked teeth at the base of each semicell that alternate with those on the other semicell. Morphology of the type species, Actinodontum lomaense (Alfinito et Mazzoni) Alfinito et Coesel, is dealt with in much detail. Cosmarium basituberculoides Bourrelly et Couté and Cosmarium elgonense Kusel-Fetzmann are transferred to the new genus. The geographical distribution of the genus Actinodontum is discussed. 相似文献