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1.
N. Friesen R. Fritsch K. Bachmann 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1997,95(8):1229-1238
Random amplified polymorphic DNA (RAPD) and genomic in situ hybridization (GISH) methods have been used to verify the hybridogenic
origin and to identify the parental species of some ornamental cultivars in the subgenus Melanocrommyum of the genus Allium. The cultivars had been selected from seed obtained after uncontrolled pollination in breeders’ fields. The combination of
GISH analysis with RAPD markers is very suitable for testing the hybridogenic origin of plants and to ascertain the parental
species of the hybrids in such cases. As suspected, A. macleanii and A. cristophii are the parental species of ‘Globemaster’. The parental species of cultivar ‘Globus’ are A. karataviense and A. stipitatum, and not A. cristophii and A. giganteum as has been assumed on morphological grounds. Cultivars ‘Lucy Ball’ and ‘Gladiator’ are of hybrid origin, though only one
of the parental species, A. hollandicum, could be confirmed. The cultivars ‘Purple Sensation’, ‘Mount Everest’, ‘White Giant’, ‘Michael H. Hoog’ and ‘Mars’ are not
hybrids since neither GISH nor RAPD suggest the presence of a second genome. ‘Purple Sensation’ belongs to A. hollandicum, ‘Mount Everest’, ‘White Giant’ and ‘Mars’ to A. stipitatum,‘Michael H. Hoog’ to A. rosenorum.
Received: 3 July 1997 / Accepted: 9 October 1997 相似文献
2.
Four new and one unidentified species of Neohaliotrema Yamaguti, 1965 were obtained from the gills of the Indo-Pacific sergeant Abudefduf vaigensis (Quoy & Gaimard) off Pulau Langkawi, Malaysia. The five species, N. malayense n. sp., N. bombini n. sp., N. andamanense n. sp., N. parvum n. sp. and an unidentified Neohaliotrema sp. (similar to N. macracanthum Zhukov, 1976), are described and distinguished based mainly on features of the haptor. Species of this genus are divisible
into two groups, the ‘maomao group’, with two pairs of morphometrically modified ‘marginal’ hooks and a fenestrated haptor,
and the ‘gracile group’, with morphologically similar marginal hooks and an entire haptor. With the exception of N. bombini n. sp., the species described fit within the ‘maomao group’. It is suggested that the more complex Neohaliotrema species of the ‘maomao group’ have modified hooks 1 and 2 on a haptoral ‘isthmus’ between two large apertures, i.e. ‘windows’,
whereas the less complex species lacking these features are those of the ‘gracile group’. Neohaliotrema spp. have only a single pair of pigmented eye-spots. A fenestrated haptor is unique to the Neohaliotrema spp. of the ‘maomao group’. The generic diagnosis of Neohaliotrema is amended to include new data and a key to its known species is presented. 相似文献
3.
Wild and cultured winter flounder Pseudopleuronectes americanus (Walbaum) from Passamaquoddy Bay were surveyed for species of Gyrodactylus Nordmann, 1832. Two species were found: G. pleuronecti Cone, 1981 and G. aideni n. sp, both members of Malmberg’s ‘groenlandicus group’. Although the hard parts in the haptor are very similar in the two
species, hamuli of G. aideni are consistently shorter than those of G. pleuronecti. The two species differed by 35 base pairs in the ITS 1, 5.8 and ITS 2 region. A BLAST search identified a variety of species
of Gyrodactylus from marine fishes in the Atlantic Ocean as closest matches, indicating the ‘groenlandicus group’ is part of a major marine
lineage within Gyrodactylus (sensu lato) that has successfully radiated among coastal percid, pleuronectid, cottid and anarhichadid fishes. Exposure experiments
suggested that winter flounder is the primary host of both species of parasites and that three other pleuronectid species
in the bay may potentially serve only as occasional transport hosts. 相似文献
4.
Specimens of the greasy grouper Epinephelus tauvina (Forssk?l), caught off Moorea, French Polynesia, harboured four species of gill monogeneans. The diplectanid Pseudorhabdosynochus pai n. sp. is characterised by an extremely big male quadriloculate organ (inner length 77 μm, cone length 15, tube length 47),
the largest of all members of the genus, and a sclerotised vagina with a very complex structure, including three secondary
chambers instead of one as in most species. Pseudorhabdosynochus sp. is a species of the ‘cupatus group’; this species is not formally described but various measurements are provided. The
ancyrocephalid Haliotrema sp. and the capsalid Benedenia sp. were rare; they are both mentioned but not described. The diplectanid fauna of E. tauvina corresponds to the pattern already found in a clade of grouper species, the members of which often harbour both a species
of the ‘cupatus group’ and another species of Pseudorhabdosynochus Yamaguti, 1958.
Résumé Des spécimens du mérou Epinephelus tauvina (Forssk?l) pêchés à Moorea, Polynésie Fran?aise, hébergeaient quatre espèces de monogènes sur les branchies. Le Diplectanidae Pseudorhabdosynochus pai n. sp. est caractérisé par un organe tétraloculé male de très grande taille (longueur interne 77 μm, longueur du c?ne 15, longueur du tube 47), le plus grand de toutes les espèces du genre, et un vagin sclérifié à structure très complexe, comprenant trois chambres secondaires, au lieu d’une comme c’est le cas chez la plupart des autres espèces. Pseudorhabdosynochus sp. est une espèce du ‘groupe cupatus’ qui n’est pas formellement décrite, mais des mesures sont indiquées. Un Ancyrocephalidae, Haliotrema sp., et un Capsalidae, Benedenia sp., étaient rares, et sont mentionnés mais non décrits. La faune des Diplectanidae de E. tauvina correspond au patron déjà trouvé dans un clade d’espèces de mérous, dont les membres hébergent souvent à la fois une espèce du ‘groupe cupatus’ et une autre espèce de Pseudorhabdosynochus Yamaguti, 1958.相似文献
5.
K. Sorkheh B. Shiran M. Khodambshi V. Rouhi S. Ercisli 《Plant Cell, Tissue and Organ Culture》2011,105(3):395-404
Eight native Iranian almond species from three sections, ‘Euamygdalus’ (Prunus communis; Prunus eleagnifolia and Prunus orientalis); ‘Lycioides’ (Prunus lycioides and Prunus reuteri) and ‘Spartioides’ (Prunus arabica, Prunus glauca and Prunus scoparia) were in vitro screened for drought tolerance using sorbitol and polyethylene glycol (PEG) as an osmoticum. Different levels
of water stress were induced using five concentrations of either sorbitol or polyethylene glycol in Woody Plant Medium (WPM).
Water potential of various media ranged from −0.80 to −2.05 MPa and water stress in culture medium adversely affected plantlet
growth. Wild species from ‘Spartioides’ were less affected than ‘Lycioides’ and ‘Euamygdalus’. At the same level of water
potential, sorbitol had lower adverse effects than PEG; the latter being severe. Prunus × sorbitol and Prunus × PEG interactions were significant. At 0.2 M sorbitol and 0.003 M PEG, ‘Spartioides’ produced significantly more roots with
higher total root length and root volume, as well as root-dry weight than those of ‘Lycioides’ and ‘Euamygdalus.’ It is concluded
that in vitro screening of native Iranian almond species under specific and limited water-stress conditions may provide a
system for effectively differentiating the wild species of almond for their expected root mass production under field conditions. 相似文献
6.
Ming-Min Lee Mathieu Sicard Marjorie Skeie S. Patricia Stock 《Systematic parasitology》2009,72(2):127-141
A new entomopathogenic nematode, Steinernema boemarei n. sp., is described from southern France. Morphological, molecular (28S and ITS rDNA sequence data) and cross-hybridisation
studies were used for diagnostics and identification purposes. Both molecular and morphological data indicate that the new
species belongs to the ‘glaseri-group’ of Steinernema spp. Key morphological diagnostic traits for S. boemarei n. sp. include the presence of prominent deirids (cervical papillae) on adult males, the morphology of the spicules and gubernaculum,
and the arrangement of the 23 genital papillae of the first generation males. Additionally, morphometric traits of the third-stage
infective juvenile, including total body length (mean 1,103 μm), tail length (mean 86 μm), location of the excretory pore
(mean 91 μm), and D% (mean 63), E% (mean 106) and H% (mean 41) values are definitive. In addition to these morphological characters,
analysis of both 28S and ITS rDNA sequences depict this Steinernema species as a distinct and unique entity. 相似文献
7.
A new species of parasitic nematode, Neoascarophis macrouri n. sp. (Cystidicolidae), is described from the stomach and stomach wall of the marine deep-water fish Macrourus berglax (onion-eye grenadier) in the eastern Greenland Sea (North Atlantic Ocean). The new species, studied using both light and scanning electron microscopy, is characterised mainly by the location of the vulva near the posterior end of the body (a short distance anterior to the anus), non-filamented eggs, the structure of the mouth, a short vestibule and the length of the spicules (567–615 and 144–156 μm). Metabronema insulanum Solov’eva, 1991 is transferred to Neoascarophis as N. insulana (Solov’eva, 1991) n. comb. 相似文献
8.
Donald H. Colless 《Biology & philosophy》2006,21(3):353-367
The recognition of species proceeds by two fairly distinct phases: (1) the sorting of individuals into groups or basic taxa (‘discovery’) (2) the checking of those taxa as candidates for species-hood (‘justification’). The target here is a rational
reconstruction of phase 1, beginning with a discussion of key terms. The transmission of ‘meaning’ is regarded as bimodal:
definition states the intension of the term, and diagnosis provides a disjunction of criteria for recognition of its extension. The two are connected by a spectrum, with purely theoretical
definition at one pole and purely ‘operational’ diagnosis at the other, with the more operational elements explained by the more theoretical. The current plethora of species concepts provides a good example. Accepting the Ghiselin–Hull thesis,
that a species is an individual, a basic taxon is therefore also an individual with organisms as its parts. In a generalised
synchronic individual its parts are conceptually integrated by an integrating principle (IP), which consists of a relation applying within a plan or rule. Fully developed, such an IP ensures the maximisation of the information content of the individual. A diachronic individual is then the set of its component synchronic parts, and its IP is provided by near-identity in an appropriate space-time (not necessarily physical).
The integration of parts of an individual is illuminated by Gasking's concept of a proper group (in this case a chain-group), whose members are related by the relation serially fitting together with, the IP completed by an appropriate plan or rule. Gasking also applied the term cluster to a proper group persisting over a substantial period of time, individuated by any member acting as focus. A basic taxon is therefore a cluster of individuals, integrated by the relation significantly taxonomically similar and the rule in character-space-time. The nature of those concepts is discussed and defended. A species will inherit certain of the attributes of the preceding
basic taxon (taxa). In at least the synchronic version its parts (individuals) will resemble each other significantly, providing
the intuitive applicability of ‘members of’ and ‘instances of’ a species. Also, the notion that a species’ name is given by
pure ostension, via a name-bearer (holotype) is empirically incoherent: the name cannot be applied in practice without an
appropriate set of diagnostic traits. 相似文献
9.
Our previous study revealed that, when exposed to light from below, fruit-bodies of humus-borne agarics grow straight downward
both in the ‘Coprinus Type’ and ’Non-Coprinus Type’ species and that, in the latter, gills tilt by gravitropism, caps swell and wave, and stipes twist. The present study revealed
that fruit-bodies of some lignicolous agarics also grew straight downward. Among themFlammulina velutipes andHypsizygus marmoreus fruit-bodies showed almost the same behaviour as the ‘Non-Coprinus Type’, butPleurotus ostreatus (assumedPolyporus Type) fruit-bodies did not show the gill tilting and cap waving. Rather, it redifferentiated to produce new gills or new fruit-bodies,
possibly by gravimorphogenesis, or formed spiral stipes. Based on these results, graviresponses in hymenomycetes are overviewed. 相似文献
10.
Ulrich Einsle 《Hydrobiologia》1996,319(3):167-177
Some of the species within the genus Cyclops O. F. Müller, 1785 can only be determined exactly by combining different methods and techniques. Based on the comprehensive
analysis of morphometrical data, some populations in periodical ponds near Lake Constance were examined for their pattern
of chromatin diminution and were compared by enzyme electrophoresis. These studies provided evidence of two new species. Together
with C. furcifer Claus, 1857 and C. vicinus Uljanin, 1875 one of the ponds (‘Litzelsee’) was inhabited by four Cyclops species. In addition to morphological differences and distinct electrophoretic characteristics, C. furcifer and the new species differ in the timing of their chromatin diminution: C. singularis in the fourth, C. heberti in the fifth, and C. furcifer in the sixth cleavage. The qualitative course of chromatin diminution is rather similar in all three species.
The same combination of three Cyclops species (without C. vicinus) was also found in an older sample (1990) from another ephemeral pond near Lake Constance. A close genetical relationship
between the three species seems probable. 相似文献
11.
The influence of nodal rooting on branching was studied in three evolutionarily and morphologically diverse species of prostrate
clonal herbs: Tradescantia fluminensis (a monocotyledonous extreme ‘phalanx’ species), Calystegia silvatica (a dicotyledonous extreme ‘guerrilla’ species) and Trifolium repens (a dicotyledonous intermediate species). In all three, branch development from axillary buds is regulated by a positive signal
produced by roots together with inhibitory influences from both pre-existing branches and shoot apical buds (apical dominance).
Responses to nodal roots are cumulative and increased root activity leads to more vigorous bud outgrowth. In the absence of
nodal roots, a single basal root system is unable to maintain continued extension growth of the shoot. We suggest that as
individual nodal roots and stem internodes are both short-lived in these nodally-rooting clonal species, the plants’ investment
in them is minimal. Thus, in contrast to perennial species lacking nodal roots, individual root systems in prostrate clonal
herbs are small and stems have little secondary thickening and development of long-distance transport tissues. Hence the decline
in extension growth of the shoot in the absence of nodal roots could be linked to the weak development of long-distance transport
tissues in their relatively thin horizontal stems and to resource sharing between primary stems and lateral branches (as suggested
by the greater retardation of primary stem growth in the more profusely branched ‘phalanx’ species (Trifolium and Tradescantia) than in the weakly branched ‘guerrilla’ species, Calystegia). These findings are consistent with the view that the long-term persistence of genotypes of nodally-rooting prostrate species
is dependent upon them encountering the moist conditions required to facilitate the continual development of new young nodal
root systems. 相似文献
12.
Christophe Piscart Jaimie T. A. Dick David McCrisken Calum MacNeil 《Biological invasions》2009,11(9):2141-2145
Invasive species and environmental change often occur simultaneously across a habitat and therefore our understanding of their
relative roles in the decline of native species is often poor. Here, the environmental mediation of a critical interspecific
interaction, intraguild predation (IGP), was examined between invasive (Gammarus pulex) and native (G. d. celticus) freshwater amphipods. In the laboratory, IGP asymmetries (males preying on congeneric females) were examined in river water
sourced from zones where: (1) the invader has completely displaced the native; (2) the two species currently co-exist, and
(3) the native currently persists uninvaded. The invader was always a more effective IG predator, but this asymmetry was significantly
weaker moving from ‘invader-only water’ through ‘co-existence water’ to ‘native-only water’. The constituent of the water
that drives this mediation of IGP was not identified. However, balancing the rigour of laboratory experiments with field derived
‘environment’ has advanced understanding of known patterns in a native species decline, and its co-existence and persistence
in the face of an invader. 相似文献
13.
Summary A study of the bacterial microflora of muds colonized bySpartina townsendii agg. in healthy and ‘die-back’ sites in the Lymington estuary was made. No important qualitative differences were found between
the microfloras of the two types of site. Fewer species, however, were present in the die-back sites. It is suggested that
under anaerobic conditions, such as occur in a ‘die-back’ site, the bacteria will utilise such oxygen as is present, and will
then engage in anaerobic metabolic processes, producing reduced ions which will reduce the oxidation-reduction potential still
further. The occurrence of abundant sulphate reducers in the ‘die-back’ sites may be particularly significant in this respect.
No evidence was obtained of any more direct relationship between bacterial flora and the development of ‘die-back’. 相似文献
14.
15.
L. Verdoodt A. Van Haute I. J. Goderis K. De Witte J. Keulemans W. Broothaerts 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1998,96(2):294-300
To obtain homozygous genotypes of apple, we have induced haploid development of either the female or the male gametes by
parthenogenesis in situ and anther culture, respectively. Of the shoots obtained, which were mainly of a non-haploid nature,
some could be derived from fertilised egg cells or from sporophytic anther tissue. In order to select the shoots having a
true haploid origin, and thus homozygotes, we decided to use the single multi-allelic self-incompatibility gene as a molecular
marker to discriminate homozygous from heterozygous individuals. The rationale behind this approach was that diploid apple
cultivars contain 2 different alleles of the S-gene and therefore the haploid induced shoots obtained from them should have only one of the alleles of the single parent.
The parental cultivars used were ‘Idared’ (parthenogenesis in situ) and ‘Braeburn’ (androgenesis), and their S-genotypes were known, except for 1 of the ‘Braeburn’S-alleles. To stimulate parthenogenetic development ‘Idared’ styles were pollinated with irradiated ‘Baskatong’ pollen, the
S-alleles of the latter (2n) cultivar were also unknown. The cloning and sequence analysis of these 3 unidentified S-alleles, 1 from ‘Braeburn’ and 2 from ‘Baskatong’ is described, and we show that they correspond to the S
24
-, S
26
- and S
27
-alleles. We have optimised a method for analysis of the S-alleles of ‘Idared/Baskatong’- or ‘Braeburn’-derived in vitro plant tissues and have shown that this approach can be applied
for the screening of the in vitro shoots for their haploid origin.
Received: 18 August 1997 / Accepted: 10 September 1997 相似文献
16.
Effects of NaCl stress on proline and cation accumulation in salt sensitive and tolerant turfgrasses
Summary Concentrations of proline, sodium and potassium in shoot tissues of five turfgrass species were measured following exposure
to 170 mM NaCl salinity stress. Salt tolerant ‘Fults’ alkaligrass and ‘Dawson’ red fescue restricted the accumulation of Na-ions to
significatnly low levels compared to the salt sensitive Kentucky bluegrasses (‘Adelphi’ and ‘Ram I’) and ‘Jamestown’ red fescue.
Accumulation of proline began in all species within 24 h of initiation of salt stress but at a more rapid rate and higher
overall concentration for ‘Fults’ alkaligrass. Proline levels were variable and too low in relation to sodium accumulations
to have any significant osmoregulatory role in salt tolerance among all cultivars tested with the possible exception of alkaligrass. 相似文献
17.
Fotini G. Skiada Katerina Grigoriadou Eleftherios P. Eleftheriou 《Central European Journal of Biology》2010,5(6):839-852
The effects of six basal media on in vitro shoot proliferation of the greek grapevines Vitis vinifera L. cv. ‘Malagouzia’ and ‘Xinomavro’ were investigated. Galzy and Zlenco proved to be the most effective for ‘Malagouzia’
and ‘Xinomavro’, respectively. If only BA was present in the medium, shoot development was poor and the plantlets were chlorotic.
When the medium was supplemented with BA and NAA, growth was enhanced. The best ratio (in μM) of growth regulators was 0.5/0.3
for ‘Malagouzia’, and 0.1/0.03 for ‘Xinomavro’, which resulted in the highest number of microshoots per explant and greatest
proliferation rate. The development of ‘Malagouzia’ and ‘Xinomavro’ explants at 21±2 and 26±2°C was also investigated, revealing
the higher temperature to be more effective. Regarding rooting, 0.5 μM IBA improved root formation at 26°C for ‘Malagouzia’
and 0.5 μM IBA at 21°C for ‘Xinomavro’. Moreover, 0.5 μM IBA resulted in a higher rooting percentage (>95%) and proved to
be more beneficial for the overall morphological appearance of the plantlets of ‘Malagouzia’. After acclimatization, survival
of microshoots cultivated in media with IBA was higher than those in NAA. 相似文献
18.
R. H. Marrs M. G. Le Duc S. M. Smart K. J. Kirby R. G. H. Bunce P. M. Corney 《Kew Bulletin》2010,65(4):583-594
The invasion of native habitats by exotic, or alien, plant species has received considerable attention recently from policy,
research, and practical conservation management perspectives. However, a new hypothesis for species dynamics in Britain suggests
that a small number of aggressive native plant species (termed ‘thugs’) may have an equal, or greater, impact on native species
and habitats than exotic species. Here, we examine this hypothesis using multivariate techniques with field-layer cover data
collected during a country-wide survey of British woodlands. Multivariate analysis of these data identified a north-south
gradient on the first axis, and that 20 of the 25 National Vegetation Classification woodland types were sampled within the
study. The most abundant field-layer species included three of the proposed native ‘thugs’, i.e. Rubus fruticosus, Pteridium aquilinum and Hedera helix in addition to the native woodland indicator species Mercurialis perennis. Variation partitioning was used to compare the relative importance of native field-layer ‘thug’ species with invading alien
shrub and tree species relative to other environmental drivers. The variation in the field-layer data-set explained by the
three native ‘thug’ species was significant, but they explained a relatively small proportion of the variation relative to
other environmental variables (climate, soil, management factors etc.). They did, however, explain almost four times as much
variation as the three alien species that were significantly correlated with field-layer species composition (Acer pseudoplatanus, Impatiens glandulifera, Rhododendron ponticum). The results of this analysis suggest that the field-layer of British woodlands is impacted as much by native ‘thug’ species,
as it is from ‘aliens’. Concern about the impact of these native ‘thug’ species has been reported previously, but their impact
has not previously been compared to the impact of invading aliens. It is hoped that this analysis will do two things, first
to act as a sound baseline for assessing any changing balance that should occur in the future, and second, to prompt both
ecologists and conservationists to develop woodland management policies based on sound science. 相似文献
19.
Three new species of Lamellodiscus are described from four (including two undescribed) species of Gymnocranius off New Caledonia, South Pacific. All three species have a similar body anatomy and morphology of the haptoral hard parts
and are distinguished on the basis of the male copulatory organ (MCO). Lamellodiscus
tubulicornis n. sp. (type-host: G. grandoculis; other host: Gymnocranius sp. B) has an MCO with a tube and horn; L. magnicornis n. sp. (type-host: G. grandoculis; other hosts: G. euanus, Gymnocranius sp. A and Gymnocranius sp. B) has an MCO with a long horn and a membrane; L. parvicornis n. sp. (type-host: G. euanus; other hosts: G. grandoculis and Gymnocranius sp. B) has an MCO with a small horn and a membrane. Lamellodiscus epsilon Yamaguti, 1968 is redescribed based on the type-specimens (from Monotaxis grandoculis off Hawaii). Lamellodiscus sp. is recorded from Gnathodentex aureolineatus off New Caledonia. All these five species have lamellodiscs that exhibit a unique characteristic: the second lamella forms
an almost closed circle, in contrast to all other described species of Lamellodiscus in which the second lamella has the form of one or two crescents. Lamellodiscus spp. are usually classified in two groups, the ‘ignoratus’ and ‘elegans’ groups, according to the structure of the lamellodisc;
we propose a new ‘tubulicornis’ group for these five species. In addition to their lamellodisc structure, species of the tubulicornis
group are also characterised by their egg (elongate in contrast to tetrahedral in the two other groups) and their hosts (monotaxine
lethrinids as opposed to mainly sparids). The generic diagnosis of Lamellodiscus given by Amine & Euzet (2005) is amended to include species with elongate eggs. 相似文献
20.
The compositions of leaf monoterpenoids from 11 species in the Juniperus section (Juniperus chinensis var. chinensis,J. virginiana, J. communis var. montana,J. rigida, J. chinensis var. globosa,J. chinensis var. sargentii,J. chinensis ‘Kaizuka Variegata’,J. squamata ‘Wilsonii’,J. x media ‘Shimpake’,J. x media ‘Plamosa Aurea’, andJ. squamata ‘Aloderi’) were comparatively analyzed by GC-MS. Of the 24 compounds identified, α-pinene, myrcene, limonene, terpinolene,
and bornyl acetate were common to all, but particular combinations differed remarkably among taxa. The simplest composition
(eight compounds) was found in.J, chinensis var. chinensis; the most complex (19 compounds), inJ. x media ‘Shimpake’. Cluster analysis generated four distinctive clades within the Juniperus section. The minimum spanning network
revealed thatJ. squamata ‘Wilsonii’ andJ. x media ‘Shimpake’ were most similar in their chemical makeup. 相似文献