166 research outputs found
Chromosome numbers and karyotypes in Arum (Araceae)
SUMMARYChromosome morphology was studied in five species of the genus Arum (Araceae). The karyotypes of Arum orientale (2n = 28), A. alpinum (2n = 28) and A. nigrum (2n = 28) were very similar. A. pictum (2n = 28) is composed of a higher number of asymmetric chromosomes. The karyotype of A. maculatum (2n = 56) shows great similarities to the karyotypes of A. orientale and A. alpinum
Karyological Studies of Some Taxa of the Genus Ophrys (Orchidaceae) from Apulia (Italy)
SUMMARYKaryological studies of some taxa of the genus Ophrys (Orchidaceae) from Apulia are reported. Diploid chromosome number 2n = 36 was observed in all taxa studied. Correlations between each taxon's karyotype are discussed. The karyotypes of these taxa are characterized by similar chromosome types
IUCN red list evaluation of the orchidaceae endemic to apulia (Italy) and considerations on the application of the IUCN protocol to rare species
The conservation status of the ten taxonomically currently recognised orchid species and subspecies (eight in the genus Ophrys, and one each in the genera Epipactis and Serapias) endemic to Apulia (southeast Italy) is presented. Each taxon has been assessed against the internationally accepted IUCN criteria and categories. Of the ten taxa, eight ones are classified as threatened (Endangered or Vulnerable), one as Near Threatened and one as Least Concern. Given that nine of the ten analysed taxa were recently assessed, a comparison with the previous assessments is presented: 67% of the assessed taxa changed their IUCN category. Four taxa (Ophrys murgiana, O. oxyrrhynchos subsp. ingrassiae, O. peucetiae, O. tardans) are now assigned to a higher threat category, while two taxa (Ophrys gravinensis and O. oestrifera subsp. montis-gargani) are now assigned to a lower threat category. These category changes in such a very short time are due to the better knowledge on the number of mature individuals and on the threats affecting the species, and to the discovery of new occurring sites. The most important category change affects Ophrys tardans. The new assessment leads to the category Endangered, whereas in the previous assessment this species was indicated as Least Concern, i.e. as not threatened. Another species with a noteworthy category increase is Ophrys peucetiae, previously indicated as Least Concern and now assigned to the category Vulnerable. The authors discuss these results, highlighting that especially when assessing rare species with a small distribution range against the IUCN protocol, it should be taken into account that the assessment could be influenced (also noteworthy) by the effective knowledge on the distribution, on the population size and on the threats affecting the populations. As a consequence, field work is warmly suggested before assessing the threat category of rare taxa, given that an increased effort in field research often leads to the discovery of new sites and to a better estimation of the number of individuals and of the threats
Evidence from multivariate morphometric study of the quercus pubescens complex in southeast Italy
The name Quercus pubescens s.l. encompasses a complex of deciduous oak taxa with mainly southeastEuropean
distribution and a large ecological niche. As the easternmost region of Italy, Apulia is
rather isolated from a geographical and physiographical viewpoint and counts the highest number
of oak species (10). In the taxonomic and phytosociological literature, the occurrence of several
species belonging to the Quercus pubescens collective group is reported for this region. In order to
verify if different sets of morphological characters are associated with different taxa, 24 populations
of Quercus pubescens s.l. located in different ecological-geographical areas of Apulia were sampled.
A total of 367 trees, 4254 leaves and 1120 fruits were collected and morphologically analysed.
Overall, 25 morphological characters of oak leaves and fruits were statistically treated using both
univariate and multivariate analysis. Nested ANOVA showed that leaves collected from a single tree
exhibited a degree of morphological variability higher than that observed when comparing leaves
coming from different trees of the same population and from different trees of different populations
as well. Almost all the morphological characters analysed exhibited a continuous trend of variation
so that none of them can be used as a character to discriminate between populations. Only leaf
and fruit “size” and fruit petiole length emerged as slightly discriminating characters. Our results
suggest that it is unlikely that more than one species belonging to the Quercus pubescens complex
occurs in the Apulia region. Comparison between the Apulian populations and a genetically
pure Q. pubescens population coming from a different area (the Molise region) strengthened the
assumption as to the existence of a single species that can provisionally be classified under the name
of Q. pubescens s.
Comparative chromosome studies in species of subtribe Orchidinae (Orchidaceae)
In our study, FISH mapping using 18S-5.8S-25S rDNA and 5S rDNA sequences was performed for the first time on Ophrys tenthredinifera Willdenow, 1805, Serapias vomeracea (Burman f., 1770) Briquet, 1910 and Himantoglossum hircinum (Linnaeus, 1753) Sprengel, 1826. A detailed study was also performed on O. tenthredinifera using Giemsa-staining, silver-staining, CMA fluorescence banding and fluorescence in situ hybridisation (FISH) with rDNA probes. We analysed two subspecies, i.e. O. tenthredinifera subsp. neglecta (Parlatore, 1860) E.G. Camus, 1908 and O. tenthredinifera subsp. grandiflora (Tenore, 1819) Kreutz, 2004 by the traditional Feulgen method and constructed the karyotype. The cytotaxonomic implications for both taxa are also discussed. In Himantoglossum hircinum, FISH and silver staining highlighted differences in the number of two rDNA families (35S and 5S) with respect to Barlia robertiana (Loiseleur-Deslongchamps, 1807) Greuter, 1967. In addition, fluorescence in situ hybridisation was also applied to diploid (2n = 2x = 36) and triploid (2n = 3x = 54) Anacamptis morio (Linnaeus, 1753) R.M. Bateman, Pridgeon et M.W. Chase, 1997. As far as we are aware, this is the first case of autotriploidy observed in A. morio
Understanding perspective taking and its role in relation to teamworking and diversity
In the current thesis I focus on perspective taking as a fundamental social process guiding productive and cooperative interactions within and between work teams. I define perspective taking as the effortful and effective understanding of diverse cognitions, emotions, and identities tied to particular targets in particular situations. Little attention has been given to perspective taking as a situational or state concept that can vary across groups, time, and contexts. Previous research has typically treated it as a stable personality difference or a temporary mindset induced in laboratory settings. In this thesis, I conduct three studies with data collected from Masters of Business Administration (MBA) study teams and one final study with military teams to examine how perspective taking supports effective teamwork interactions. In the first study, I use data collected from MBA team members to develop and validate three self-report, state indicator measures of active perspective taking: effort, empathic concern, and positive attributions. In the second study, I demonstrate positive reciprocal relationships over time between the three perspective taking indicators and cooperative team member outcomes. In the third study, I show that entire MBA teams can exhibit shared perspective taking at the team level of analysis. The results also confirm that team perspective taking indicators mediate between team diversity and team states of potency and reflexivity. In the final study, I develop a self-report measure of team perspective taking effectiveness or understanding and show that it is positively related to perceived performance, helping, and morale in military teams. I show that team perspective taking effectiveness is supported by elaboration of task perspectives and effective perspective taking for the external targets of other teams. The practical and research implications of the studies for understanding situational perspective taking, team effectiveness, and finding value in team diversity are discussed.EThOS - Electronic Theses Online ServiceGBUnited Kingdo
Structural basis for DNA strand separation by a hexameric replicative helicase
Hexameric helicases are processive DNA unwinding machines but how they engage with a replication fork during unwinding is unknown. Using electron microscopy and single particle analysis we determined structures of the intact hexameric helicase E1 from papillomavirus and two complexes of E1 bound to a DNA replication fork end-labelled with protein tags. By labelling a DNA replication fork with streptavidin (dsDNA end) and Fab (5′ ssDNA) we located the positions of these labels on the helicase surface, showing that at least 10 bp of dsDNA enter the E1 helicase via a side tunnel. In the currently accepted ‘steric exclusion’ model for dsDNA unwinding, the active 3′ ssDNA strand is pulled through a central tunnel of the helicase motor domain as the dsDNA strands are wedged apart outside the protein assembly. Our structural observations together with nuclease footprinting assays indicate otherwise: strand separation is taking place inside E1 in a chamber above the helicase domain and the 5′ passive ssDNA strands exits the assembly through a separate tunnel opposite to the dsDNA entry point. Our data therefore suggest an alternative to the current general model for DNA unwinding by hexameric helicases
Global and regional IUCN Red List assessments: 7
In this contribution, the conservation status assessment of four vascular plants according to IUCN categories
and criteria are presented. It includes the assessments of Aurinia leucadea (Guss.) K.Koch, Chondrilla chondrilloides
(Ard.) H.Karst., Daphne cneorum L., and Ophioglossum azoricum C.Presl at regional level (Italy)
Notulae to the Italian native vascular flora: 3.
In this contribution new data concerning the distribution of native vascular flora in Italy are presented. It includes new records, exclusions, and confirmations to the Italian administrative regions for taxa in the genera Asplenium, Bolboschoenus, Botrychium, Chamaerops, Crocus, Galeopsis, Grafia, Helosciadium, Hieracium, Juniperus, Leucanthemum, Lolium, Medicago, Phalaris, Piptatherum, Potamogeton, Salicornia, Salvia, Seseli, Silene, Spiraea, Torilis and Vicia. Rhaponticoides calabrica is proposed as synonym novum of R. centaurium. Furthermore, new combinations in the genera Galatella and Lactuca are proposed
An updated checklist of the vascular flora native to Italy
An updated inventory of the native vascular flora of Italy, providing details on the occurrence at regional level, is presented. The checklist includes 8195 taxa (6417 species and 1778 subspecies), distributed in 1092 genera and 152 families; 23 taxa are lycophytes, 108 ferns and fern allies, 30 gymnosperms and 8034 angiosperms. The taxa currently occurring in Italy are 7483, while 568 taxa have not been confirmed in recent times, 99 are doubtfully occurring in the country and 19 are data deficient. Out of the 568 not confirmed taxa, 26 are considered extinct or possibly extinct
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