Search results for "crib"
showing 10 items of 280 documents
ITS region of Pythium canariense sp. nov., its morphology and its interaction with Botrytis cinerea.
2002
A new species Pythium canariense (CI-07), isolated from soil samples taken in the San Nicolas region of the Canary islands (Gran Canaria, Spain), is being described here. This species is characterised by its spherical to pyriform, intercalary to catenulate sporangia, smooth-walled terminal oogonia supplied with monoclinous and diclinous antheridia which at times are branched and wrap around the female gametangia. The fungus has an antagonistic effect on Botrytis cinerea, the grey mould fungus. Morphological features are being given here together with the sequence of the complete internal transcribed spacer region of the nuclear ribosomal DNA of the fungus, its comparison with related specie…
ITS1 region of the rDNA of Pythium megacarpum sp. nov., its taxonomy, and its comparison with related species.
2000
Pythium megacarpum sp. nov., was isolated from a soil sample taken from a wheat field in Lille in northern France. It was mistakenly described as Pythium ostracodes Drechsler [Paul, B (1994) Cryptogam. -Mycol. 15,263-271]. Despite morphological resemblance, the comparison between the internal transcribed spacer (ITS)1 regions of the rDNA of the two fungi, leaves no doubt of their different identities. This species is unique because of its large oogonia and plerotic, thick walled oospores, its monoclinous antheridia with large antheridial cells and its lack of zoospores. The character combination of P. megacarpum and the ITS1 sequence of its rDNA, justifies the creation of a new species with…
Culturable endophytic microbial communities in the circumpolar grass,Deschampsia flexuosain a sub-Arctic inland primary succession are habitat and gr…
2014
Summary Little is known about endophytic microbes in cold climate plants and how their communities are formed. We compared culturable putative endophytic bacteria and fungi in the ecologically important circumpolar grass, Deschampsia flexuosa growing in two successional stages of subarctic sand dune (68°29′N). Sequence analyses of partial 16S rRNA and internal transcribed spacer (ITS) sequences of culturable endophytes showed that diverse bacteria and fungi inhabit different tissues of D. flexuosa. A total of 178 bacterial isolates representing seven taxonomic divisions, Alpha, Beta and Gammaproteobacteria, Actinobacteria, Bacteroidetes, Firmicutes and Acidobacteria, and 30 fungal isolates …
Evolutionary significance of the invasion of introduced populations into the native range of Meconopsis cambrica
2011
The long history of the deliberate or accidental and human-mediated dispersal of flowering plants has led to the introduction of foreign genotypes of many species into areas of Europe hitherto occupied by potentially distinct native populations. Studies of the genetic and evolutionary consequences of such changes are handicapped by the difficulty of identifying the surviving native populations of many species in the absence of clear morphological differences. We investigated the relationship between putative native and introduced populations of the herbaceous perennial Meconopsis cambrica (Papaveraceae), as the isolated native populations of this species can be identified by historical and …
What is the origin of the Scottish populations of the European endemic Cherleria sedoides (Caryophyllaceae)?
2015
Cherleria sedoides L. (Minuartia sedoides (L.) Hiern) is a montane perennial which, with some species in Minuartia sect. Spectabiles, is more closely related to Scleranthus than to other Minuartia species and is therefore best restored to the reinstated and redefined genus Cherleria. Reconstruction of the ancestral area of the clade containing C. sedoides suggests that it evolved in the Alps or the Balkan peninsula. The species now has an unusual distribution, being present in the mountains of southern Europe and Scotland but absent from the Arctic. Three historical scenarios that might have led to the presence of the species in Scotland are outlined and tested by a molecular analysis compa…
Is Welsh Poppy,Meconopsis cambrica(L.) Vig. (Papaveraceae), truly aMeconopsis?
2011
AbstractSince the nineteenth century, the western European endemic Meconopsis cambrica has been regarded as the only European representative of the genus Meconopsis Vig. This genus, which is otherwise restricted to the Himalayas, differs from Papaver in having a style rather than a stigmatic disc. A phylogenetic reconstruction using 65 internal transcribed spacer sequences of 62 taxa of Old World Papaveroideae and three outgroup taxa shows that M. cambrica is not the closest relative of the remainder of Meconopsis but rather the closest sampled relative of Papaver s.str. This is consistent with morphological evidence which suggests that the style evolved independently in M. cambrica from a …
<p><strong><em>Diversispora valentina</em></strong><strong> (Diversisporaceae), a new species of arbuscular mycor…
2020
A new arbuscular mycorrhizal fungal species, Diversispora valentina, is described and illustrated. In the field, this species is associated with marine dunes located along the Mediterranean coast in eastern Spain. Spores of D. valentina occurred in sporocarps, in clusters, and singly in the soil or inside the roots of Ammophila arenaria (Poaceae), Elymus farctus (Poaceae), Otanthus maritimus (Asteraceae), and Echinophora spinosa (Apiaceae) in the six locations studied. A single-species culture of D. valentina was obtained using Trifolium repens as a host plant. The small subunit internal transcribed spacer and large subunit (SSU-ITS1-5.8S-ITS2-LSU) nrDNA sequences place the new species in t…
Hybridization and competition between the endangered sea marigold (Calendula maritima, Asteraceae) and a more common congener
2013
Occurrences of hybridization between the rare, endangered Sicilian endemic, Calendula maritima, and other congeners in the wild have been suspected by several authors, but never demonstrated. In San Cusumano (Trapani), one of the only three Sicilian mainland populations, C. maritima occurs in close proximity to the more common congener C. suffruticosa subsp. fulgida, and individuals morphologically intermediate between the two taxa have been observed. In order to determine whether hybridization is occurring at this site, and, if so, begin to assess the impact it could have on C. maritima, two independent tests of hybridity were conducted by studying (1) the pollen morphology and viability a…
Responses of soil decomposer animals to wood-ash fertilisation and burning in a coniferous forest stand
2000
Abstract Responses of soil decomposer animals (enchytraeids and microarthropods) to wood-ash fertilisation (1000 and 5000 kg ha−1) and a fire treatment mimicking prescribed burning were studied in a Scots pine stand in central Finland. The experiment was conducted on 30 × 30 m2 plots, each treatment being replicated four times. Soil animals were sampled throughout the growing season in the third year after the treatments. As a rule, numbers of soil animals increased during the study period. Numbers of the only enchytraeid worm species found at the study site, Cognettia sphagnetorum, were lower in the plots with higher ash level and plots which have been burned. In the plots having these tre…
Harmonic balance analysis of pull-in range and oscillatory behavior of third-order type 2 analog PLLs
2020
The most important design parameters of each phase-locked loop (PLL) are the local and global stability properties, and the pull-in range. To extend the pull-in range, engineers often use type 2 PLLs. However, the engineering design relies on approximations which prevent a full exploitation of the benefits of type 2 PLLs. Using an exact mathematical model and relying on a rigorous mathematical thinking this problem is revisited here and the stability and pull-in properties of the third-order type 2 analog PLLs are determined. Both the local and global stability conditions are derived. As a new idea, the harmonic balance method is used to derive the global stability conditions. That approach…