Добірка наукової літератури з теми "Ranunculus fluitans"

Biomass allocation to anchoring structures in 10 species of aquatic macrophytes in two types of the cool and humid temperate climate in Europe, subcontionental (NW Poland) and Atlantic (W France), was examined. The study focused on the weight of anchoring organs in <em>Chara delicatula</em> Ag., <em>Ch. fragilis</em> Desv., <em>Juncus bulbosus</em> L., <em>Littorella uniflora</em> (L.) Asch., <em>Luronium natans</em> (L.) Raf., <em>Potamogeton pectinatus</em> L., <em>P. perfoliatus </em>L., <em>P. natans</em> L. and <em>Ranunculus fluitans</em> (Lam.) Wimm., as well as submerged structures in <em>Hydrocharis morsus-ranae</em> L. The plants were collected from 10 geographically distant lakes and 2 rivers with a current velocity of 0.3-0.5 m s^-1. It was assumed that biomass allocation to anchoring structures in rooting macrophytes depends on the time that mechanical forces, which can remove the plants from the occupied area, exert their effect. It was found that, in the Atlantic and subcontinental climates, the ratio between the biomass of underground (or submerged) and above-ground structures (U/A index), calculated for the ramets of <em>Chara fragilis</em>, <em>Hydrocharis morsus-ranae</em> and <em>Ranunculus fluitans</em>, has similar values (p&gt;0.05). Nevertheless, among seven species of <em>Cormophyta</em>, which were anchored in the lake or pond littoral, six (<em>Juncus bulbosus</em>, <em>Littorella uniflora</em>, <em>Luronium natans</em>, <em>Potamogeton pectinatus</em>, <em>P. perfoliatus</em> and <em>P. natans</em>) had higher values of the U/A index in the Atlantic climate than in the subcontinental type (p &lt; 0.05). This can be explained by the lack of ice cover and, consequently, a longer time of wave action than in the subcontinental climate.

Abstract During a 1-year longitudinal study, water, sediment and water plants from two creeks and one pond were sampled monthly and analyzed for the presence of Listeria species. A total of 90 % of 30 sediment samples, 84 % of 31 water plant samples and 67 % of 36 water samples were tested positive. Generally, most probable number counts ranged between 1 and 40 g−1, only occasionally >110 cfu g−1 were detected. Species differentiation based on FT-IR spectroscopy and multiplex PCR of a total of 1220 isolates revealed L. innocua (46 %), L. seeligeri (27 %), L. monocytogenes (25 %) and L. ivanovii (2 %). Titers and species compositions were similar during all seasons. While the species distributions in sediments and associated Ranunculus fluitans plants appeared to be similar in both creeks, RAPD typing did not provide conclusive evidence that the populations of these environments were connected. It is concluded that (i) the fresh-water sediments and water plants are year-round populated by Listeria, (ii) no clear preference for growth in habitats as different as sediments and water plants was found and (iii) the RAPD-based intraspecific biodiversity is high compared to the low population density.

In the paper the phytocoenotic diversity of gray alder forests, common in the South-Western Nechernozemye of Russia, is characterized. On the territory of studies A. incana occurs in Bryansk, Kaluga, Smolensk and Orel regions. In the European Russia gray alder forests represented by a lot of forest types described by T. A. Rabotnov (1939), A. A. Nitsenko (1972), V. I. Vasilevich (1998), S. V. Degteva (2002), N. S. Liksakova (2004) etc. At the southeastern border of A. incana distribution in the South-Western Nechernozemye of Russia the gray alder forests are presented by mesophytic and hygrophytic ecologic-dynamic groups. Hygrophytic forests probably represent the azonal-zonal type of forest vegetation which is widespread in the valleys of rivers and streams. They are characterized by the presence and high constancy of hygrophyte and helophytic species. These forests belong to the alliance Alnion incanae, but they have essential floristic differences with hygrophyte alder forests of the Central Europe. Plant communities described from the South-Western Nechernozemye of Russia are characterized by a lack of Western- and Central European species, which are widely represented in Germany, Poland, Slovakia, Czech Republic and partly Ukraine: Acer pseudoplatanus, Carex brizoides, Circaea lutetiana, Chaerophyllum hirsutum, Geranium phaeum, Euonymus europaea, Lysimachia nemorum, Primula elatior, Ranunculus lanuginosus, Sambucus nigra, Viola reichenbachiana. In the Central Europe the communities of the ass. Alnetum incanae include the constantly-varying species: Abies alba, Anthriscus nitida, Astrantia major, Carduus personata, Carex remota, Carpinus betulus, Chrysosplenium oppositifolium, Cruciata glabra, Dactylis polygama, Doronicum austriacum, Euphorbia amygdaloides, Fagus sylvatica, Gentiana asclepiadea, Heracleum sphondylium, Petasites albus, P. hybridus, Prenanthes purpurea, Salvia glutinosa, Senecio nemorensis, S. ovatus, Symphytum cordatum, Valeriana dioica, etc. In communities of the Northern part of European Russia absent some nemoral species: Acer platanoides, Adoxa moschatellina, Ajuga reptans, Brachypodium sylvaticum, Carex sylvatica, Corylus avellana, Daphne mezereum, Galium odoratum, Fraxinus excelsior, Lamium maculatum, Mercurialis perennis, Poa nemoralis, Quercus robur, Ranunculus auricomus, R. cassubicus, Scrophularia nodosa, Stachys silvatica, Tilia cordata, Ulmus glabra. These species are more widely represented in Central European forests, as well as in communities of the South-Western Nechernozemye of Russia – near the southern border of the hemiboreal forests. The results of the floristic comparison do not allow considering our forests to be belong to the ass. Alnetum incanae Lüdi 1921 distinguished for the Central Europe Therefore they are allocated in the new ass. Scirpo sylvatici―Alnetum incanae ass. nov. hoc loco. The plant communities differentiate the block of predominantly helophyte and hygrophyte species characteristic for riparian habitats and communities of wetland forests: Agrostis canina, Calliergon cordifolium, Juncus effusus, Glyceria fluitans, Lycopus europaeus, Scirpus sylvaticus, Solanum dulcamara, Stachys palustris. Two variants of the association were discribed. Chaerophyllum aromaticum var. communities are characterized by the dominance of nitrophilous species Chaerophyllum aromaticum. Var. typica combines typical communities and it has no own diagnostic species. The mesophytic alder forests of the Southern Nechernozemye of Russia represent stages of demutation restoration of the mesic spruce and broad-leaved-spruce forests of the order Fagetalia sylvaticae. The specified successional status does not allow considering the mesophytic communities of a gray alder as an independent association. More correct to refer them to the temporary facies of ass. Rhodobryo rosei―Piceetum abietis Korotkov 1986, similar to the secondary birch and aspen forests representing widespread changes of the mesophytic spruce and broad-leaved-spruce forests. This facies is characterized for three variants established by the dominance of some plant species. The most mesophytic forests are represented by var. Galeobdolon luteum, which differentiated by mesophytic species of spruce and broad-leaved-spruce forests: Galeobdolon luteum, Corylus avellana, Stellaria holostea. Communities with abundant undergrowth of Padus avium, formed along the margins of forest swamps in wet loam, were classified as var. Padus avium. Its diagnostic species are following: Padus avium, Crepis paludosa, Stachys sylvatica. Var. typica combines typical communities and it has no own diagnostic species as well. The floristic peculiarities and a role of the ecological factors in differentiation of syntaxa are demonstrated by the DCA-ordination. Communities of the South-Western Nechernozemye of Russia are largely differentiated from the others on the complex gradient corresponding increase in soil moisture, light and temperature. In general, the DCA-1 axis can be regarded as a complex gradient of continentality, soil richness, and the reaction of the substrate; DCA-2 – soil moisture, temperature, and light.

AbstractUnderstanding the genetic variability of hybrids provides information on their current and future evolutionary role. In this paper, we focus on the interspecific hybrid Ranunculus circinatus × R. fluitans that forms spontaneously within the group Ranuculus L. sect. Batrachium DC. (Ranunculaceae Juss.). Genome-wide DNA fingerprinting using amplified fragment length polymorphisms (AFLP) was employed to determine the genetic variation among 36 riverine populations of the hybrid and their parental species. The results demonstrate a strong genetic structure of R. circinatus × R. fluitans within Poland (Central Europe), which is attributed to independent hybridization events, sterility of hybrid individuals, vegetative propagation, and isolation through geographical distance within populations. The hybrid R. circinatus × R. fluitans is a sterile triploid, but, as we have shown in this study, it may participate in subsequent hybridization events, resulting in a ploidy change that can lead to spontaneous fertility recovery. The ability to produce unreduced female gametes of the hybrid R. circinatus × R. fluitans and the parental species R. fluitans is an important evolutionary mechanism in Ranunculus sect. Batrachium that could give rise to new taxa.

AbstractWe demonstrate a wide distribution and abundance of hybrids between the river species Ranunculus aquatilis, R. fluitans and R. kauffmannii with the still water species R. circinatus (Batrachium, Ranunculaceae) in rivers of two postglacial landscapes of East Europe, i.e., Lithuania and Central European Russia. The Batrachium species and hybrid diversity is higher in the rivers of Lithuania (4 species and 3 hybrids vs. 2 and 1) and represented mainly by western R. aquatilis, R. fluitans and their hybrids whereas in Central European Russia, the East European species R. kauffmannii and its hybrid are the only dominant forms. Hybrids make up about 3/4 of the studied individuals found in 3/4 of the studied river localities in Lithuania and 1/3 of the individuals found in 1/3 of the localities in Central European Russia. Such extensive hybridization in river Batrachium may have arisen due to the specificity of rivers as open-type ecosystems. It may have been intensified by the transformation of river ecosystems by human activities and the postglacial character of the studied landscapes combined with ongoing climate change. Almost all hybrids of R. aquatilis, R. fluitans and R. kauffmannii originated from unidirectional crossings in which R. circinatus acted as a pollen donor. Such crossings could be driven by higher frequency and abundance of R. circinatus populations as well as by some biological mechanisms. Two hybrids, R. circinatus × R. fluitans and R. circinatus × R. kauffmannii, were formally described as R. × redundans and R. × absconditus. We found a hybrid which most likely originated from additional crossing between R. aquatilis and R. circinatus × R. fluitans.

AbstractRanunculus species grouped in the section Batrachium (water crowfoots) indicate the most valuable fluvial habitat in Europe under the EU Habitats Directive, and recognition of their environmental preferences plays a crucial role in efficient conservation. Moreover, water crowfoots are used in various monitoring systems throughout Europe. The aim of this study was to identify the distribution patterns of two common water crowfoot species (Ranunculus fluitans, R. circinatus) and their hybrid (R. circinatus × R. fluitans) in relation to environmental variables in rivers. Various chemical and hydromorphological parameters were estimated for 54 river sites where 58 different Batrachium populations were recorded. Our study revealed the most distinct positive reaction of R. fluitans to rhithral conditions characterized by rapid currents and coarse substrate. R. circinatus × R. fluitans preferred larger channels, although this taxon also flourished in rhithral rivers. The preferences of R. circinatus were not so evident confirming its occurrence under a wide range of habitat conditions. The ecological reaction of the hybrid was compared with its parental species, revealing their ecological specificity, which is useful in designing appropriate conservation programmes.