This paper focuses on the morphology, taxonomy and ecology of the widespread cyanobacteria of the genus Nodularia Mertens ex Bornet & Flahault. In this study the benthic strain of N. sphaerocarpa, isolated from a sand-pit near Olomouc (Czech Republic), is compared with brackish and seawater strains. Changes in morphology and growth parameters (biomass and chlorophyll a) recorded in varying salinity gradients were studied and a 16S rRNA sequencing and AFLP analysis conducted. Morphological and ecophysiological characteristics found were in congruence with molecular data. Three major subgroups of the benthic Nodularia (N. sphaerocarpa, N. moravica and N. harveyana) were found using the polyphasic approach. The results of both the molecular and morphological study clearly separated N. moravica and N. sphaerocarpa, as freshwater species preferring a low salinity and the N. harveyana strains originating from a marine environment preferring a high salinity.
The taxonomy of myxosporeans was traditionally dependent solely upon the spore morphological and morphometric data. Intensive reports of intraspecific morphological variation, however, are increasingly challenging the taxonomic approaches for myxosporeans. In the present work, the morphological pleomorphism of myxospores of Myxobolus drjagini (Akhmerov, 1954) was observed. More interestingly, all of these pleomorphic myxospores occurred in the same plasmodium of M. drjagini, which refutes the previous hypothesis that morphological variation of M. drjagini was derived from its responses to differences in nutrition and immunological responses associated with different host tissues. Bearing the intraspecific morphometric and morphotype variation in mind, the combination of morphological, ecological and molecular data should be applied to the species identification and delimitation for myxosporeans. This is the first reported myxobolid species with high pleomorphic myxospores which are present in the same plasmodium.
We tested the hypothesis that invasive (IN) species could capture resources more rapidly and efficiently than noninvasive (NIN) species. Two IN alien species, Ageratina adenophora and Chromolaena odorata, and one NIN alien species, Gynura sp. were compared at five irradiances. Photon-saturated photosynthetic rate (Pmax), leaf mass (LMA) and nitrogen content (NA) per unit area, and photosynthetic nitrogen utilization efficiency (PNUE) increased significantly with irradiance. LMA, NA, and PNUE all contributed to the increased Pmax, indicating that both morphological and physiological acclimation were important for the three alien species. Under stronger irradiance, PNUE was improved through changes in N allocation. With the increase of irradiance, the amount of N converted into carboxylation and bioenergetics increased, whereas that allocated to light-harvesting components decreased. The three alien species could adequately acclimate to high irradiance by increasing the ability to utilize and dissipate photon energy and decreasing the efficiency of photon capture. The two IN species survived at 4.5 % irradiance while the NIN species Gynura died, representing their different invasiveness. Ageratina generally exhibited higher respiration rate (RD) and NA. However, distinctly higher Pmax, PNUE, Pmax/RD, or Pmax/LMA were not detected in the two invasive species, nor was lower LMA. Hence the abilities to capture and utilize resources were not always associated with invasiveness of the alien species. and Y. L. Feng, J. F. Wang, W. G. Sang.
General consensus in linguistics is that language context (or ''co-text'') plays crucial role in describing linguistic properties of language items. Isolated units are, as a corollary to this statement, inherently ambiguous (polysemous and/or polyfunctional). In this paper we describe the most influential forces leading to disambiguation of language units, specifically the role of n-gram length on its ambiguity.
The most influential achievement of corpus linguistics lies in the growing importance of context in the description of language. This is also reflected by context analysis which is introduced in this paper. Context analysis is an umbrella term for a bundle of methods sharing the same hypothesis: that all the features (form, meaning, function) of the language phenomena are mirrored by the context which they enter. It is important to emphasise that by the term ''context'', it is meant here not only one or two adjacent tokens in a particular text, but all the neighbouring units (e.g. words, lemmas, part of speech tags etc.) which co-occur with a given word in all of its instances in a corpus. The paper discusses various types of context (range, type of contextual units etc.) and their effect on the analysis. By comparing contexts of distinct words or word groups we may find out what the similarities and differences are between language units, phenomena or even groups of lexemes. This type of research was conducted here to determine the relations between parts of speech.
The larval morphology of Aphodius (Plagiogonus) nanus Fairmaire, 1860 and A. (P.) arenarius (Olivier, 1789) are described and redescribed, respectively. The common characters of both species, and the specific diagnostic characters are provided and discussed. The most important morphological characters of the larvae of Plagiogonus Mulsant, 1842 are the longitudinal alignment of the anterior setae of the stipes, the spatulate form of the posterior-lateral setae of the glossae of the hypopharynx, the slight development of the anal lobe slit, the form of the epitorma of the epipharynx, the slight sclerotization of the pternotormae and the relative length of second antennal segment. A key to the larvae of both species of Plagiogonus is presented along with life history data and the preferred food of these species. This study shows that A. arenarius and A. nanus feeding habits are closer to saprophagy than to coprophagy.
The third instar larvae of three Anisoplia species, Anisoplia baetica Erichson, 1847, Anisoplia depressa Erichson, 1847 and Anisoplia remota Reitter, 1889 are described and illustrated to show the diagnostic characters of the species. The third instar larva of the monospecific genus Anthoplia, represented by Anthoplia floricola (F., 1787) is also described and illustrated. These four species are included in a revised key to the larvae of Anisopliini, which now includes four genera, and ten species. The taxonomic status of Anthoplia based on the larval morphology, is discussed.
A provisional larval groundplan of the family Hygrobiidae is provided through descriptions of internal and external features of three of six extant species, Hygrobia hermanni (Fabricius, 1775), H. wattsi Hendrich 2001 and H. australasiae (Clark, 1862) and phylogenetic interpretations. Hygrobiidae larvae are morphologically differing dramatically from all other known Adephaga by 20 autapomorphies. Structures involved with feeding, i.e., mouthparts, prepharynx and foregut are highly modified as a result of a specialisation on small tubificid worms and chironomid larvae. A placement of Hygrobiidae within Dytiscoidea is well supported by the reduced condition of the terminal abdominal segments, and the presence of 10 ancestral setae on femur and a clade comprising Hygrobiidae, Amphizoidae, and Dytiscidae by the presence of thin and elongate caudal tentorial arms, a very strong musculus verticopharyngalis and a longitudinally divided adductor tendon of the mandible. A highly modified foregut, reduced terminal spiracles VIII and the presence of tubular gills are features which distinguish hygrobiid larvae from those of other groups of Dytiscoidea (i.e, Amphizoidae, Noteridae, Dytiscidae). A sister-group relationship between Hygrobiidae and Dytiscidae is indicated by a distinctly shortened and transverse prepharynx and a cerebrum and suboesophaeal ganglion shifted to the anterior third of the head. Larvae of the Australian species H. wattsi and H. australasiae share the presence of a bluntly rounded mandible and an apical position of the primary pore MNd in instar I as potential synapomorphies.
Geographic range expansion is one of the best documented macroecological consequences of climate change. A concomitant change in morphology has been demonstrated in some species. The relationship between latitudinal variation in morphology (e.g. Bergmann's rule) and the morphological consequences of microevolutionary pressures at expanding range margins have received little attention in the literature. Here we compare morphology of males of two Palaearctic damselfly (Odonata: Zygoptera) species, Coenagrion puella (Linnaeus, 1758) and Pyrrhosoma nymphula (Sulzer, 1776). C. puella has recently expanded its range from the north of England into Scotland. P. nymphula does not exhibit a range margin in the United Kingdom and has established populations in northern Scotland. We demonstrate evidence for spatially correlated variation in body size across the sampling sites between the two species but a deviation in patterns of dispersal-related morphology. P. nymphula exhibited very weak relationships between dispersal-related morphology (wing loading and thorax : abdomen mass ratio) and latitude. However, the more southerly-distributed C. puella exhibited strong relationships between mass investment in dispersal-related morphology and latitude. These trends appear to indicate compensatory growth patterns in cooler environments like those demonstrated for other species. The limits of this compensation for conditions that are close to the limits of a species' tolerance may contribute to the determination of the range margin. Greater variation in morphology towards the range margin has been observed in previous studies in Odonata. As such, the location of the sampling sites relative to the range margin of each species (closer in C. puella than P. nymphula) is highlighted as a potential contributing factor to the variation observed.
In two successive years (2003 and 2004), a set of 16 commercial sugar beet cultivars was established in Randomized Complete Block experiments at two sites in central Greece. Cultivar combination was different between years, but not between sites. Leaf sampling took place once during the growing season and leaf area, LA [cm2], leaf midvein length, L [cm] and maximum leaf width, W [cm] were determined using an image analysis system. Leaf parameters were mainly affected by cultivars. Leaf dimensions and their squares (L2, W2) did not provide an accurate model for LA predictions. Using L×W as an independent variable, a quadratic model (y = 0.003 x2 - 1.3027 x + 296.84, r 2 = 0.970, p<0.001, n = 32) provided the most accurate estimation of LA. With compromises in accuracy, the linear relationship between L×W and LA (y = 0.5083 x + 31.928, r 2 = 0.948, p<0.001, n = 32) could be used as a prediction model thanks to its simplicity. and J. T. Tsialtas, N. Maslaris.