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Combined morphological and molecular techniques were used to characterize variation in Elymus repens. We studied the morphological variability of E. repens in relation to the degree of its genetic differentiation, in order to unravel the causes of conspicuous intraspecific morphological variation. Four populations of E. repens from different habitats were analyzed for 35 morphological characters, and their genetic differentiation was assessed by Amplified Fragment Length Polymorphism (AFLP). Four pairs of selective primers were used to detect a total of 279 AFLP bands, of which 104 (37.28%) were polymorphic between populations. Cluster analysis based on AFLP fingerprint data showed that individuals were arranged in population-specific groups. The analyses of variance (ANOVA and AMOVA) indicated significant morphological and genetic differentiation among populations (P<0.01). This study revealed low levels of AFLP variation, which suggests that conspicuous morphological variation of E. repens is caused by plasticity. E. repens is an evolutionarily young species, of hybrid origin, in which microevolutionary processes continue. This study showed that common analysis of genetic diversity and morphology is a powerful tool in low-level taxonomy.
Morphometric characters of the white seabream Diplodus sargus (Linnaeus 1758) were compared among samples collected from six marine and lagoon sites along the Tunisian coast to elucidate the impact of the geographical barrier of the Siculo-Tunisian Strait and/or the lagoon environment in the morphological variation among the Tunisian white seabream population. Two morphometric descriptors (twenty-five Truss elements and six traditional measurements) were used to study the pattern of this morphological variation. Univariate analysis of variance revealed significant differences (P < 0.001) for both traditional and Truss variables. Multivariate analysis using the two morphometric descriptors detected a clear variation in the body shape between D. sargus populations along the Tunisian coast. All these analyses showed the distinctness of the sample from El Biban lagoon compared to the remaining ones. This discrimination was due to the head and the peduncle of the studied fish. Varying degrees of differences were also observed between northern and southern samples, and between the lagoon and the marine samples. The morphologi- cal variations of the head explain also the discrimination between the different lagoons samples. Observed morphological heterogeneity seems to be related to the impact of ecological factors.
We investigated the phenotypic variation of five morphological needle characters of Scots pine (Pinus sylvestris L.) in three populations. Two of the populations occurred in bogs and the third one formed a degraded fresh pine forest showing some features of a dry pine forest. The greatest variation was found in characters a (needle length), b and d, denoting the number of stomatal rows respectively on the convex and flat sides of the needle. Conversely, characters c and e (average number of stomata per 2 mm of needle length on the convex and the flat side of the needle) were stable, with little interindividual variation. The two bog populations and the dryland population exhibited different sets of character correlations. The interpopulation differentiational detected on the basis of morphological character expression was markedly influenced by both the different edaphic conditions, and the distinct genetic structure of the studied populations.
Seed production, seedling establishment and survival into the generative phase are important stages in the life cycles of clonal species. The aim of this study was to assess the variation of generative reproduction and factors affecting its size in the natural populations of Polygonatum odoratum. It was hypothesized that: (a) seed output in a population is strongly affected by biotic and abiotic environmental factors, and weakly related to population abundance, (b) seeds’ ability to germinate and seedlings’ survival depend on the seed size. The field studies were conducted in five populations of Polygonatum odoratum in 2000–2011. Sex allocation in flowers was estimated as the number of hermaphrodite flowers on shoots and ovules in ovaries. Generative shoots, flowers and fruits on them were recorded in each population. The type and size of damage to plants by large herbivores and insects were recorded. The three sowing experiments were conducted in order to estimate seedling performance and survival. The populations differed significantly in the fraction of hermaphrodite flowers and ovule number. The number of generative shoots and flowers on them as well as the seed output significantly differentiated the populations and patches. In the first year of study, the mean seed output ranged from 0.3 to 123.7 m⁻², and it markedly decreased in two populations, where there was no seed at last years of study. Generative shoots were often grazed by roe-deer, leaves were eaten by Phymatocera aterrima and flowers were infested by Contarinia polygonati larvae. Seedling emergence was significantly correlated with the mean seed mass. Seven-year-old individuals were able to reach generative phase. In conclusions, the results suggest that the generative shoots provide a long-term inflow of seeds to the population. Under experimental conditions, substantial survival enabled the plants to potentially reach generative maturity. In studied populations, the most important reason for dynamic of seed output was animal pressure (in order – grazing, flower infestation and defoliation). The effect of these biotic factors was visible in a short period – in the current year. In contrast, the impact of abiotic factors (e.g. lighting), was appeared in a longer period.
I review geographical distribution, levels of infection and intraspecific morphological variation of Polystoma andinum Combes and Laurent, 1978 from the anuran host Melanophryniscus rubriventris. Also, I provide further information on the breeding biology of the host. The geographical distribution of P. andinum is extended further to the north and south of the original record coinciding with the major part of the range of its host. Parasite infection was recorded at seven of the eight host populations surveyed. Prevalence of infection in each population ranged from 9 to 33% and intensity from 1 to 14 parasites/host. Two morphological characters, reticulate intestine and haptor size:body length ratio, which show intraspecific consistency, readily distinguish P. andinum from each of the four species so far described in Argentina. All specimens assigned to P. andinum showed relatively wide intraspecific variation in hamulus shape. Nevertheless, morphometric analysis of five hamulus characters did not show major distinction between populations. Interlocality variability observed in this study highlights the importance of examining host samples from several localities. Reproduction of M. rubriventris in small shallow ponds is characterised by temporal and spatial uncertainty due to climatic conditions where eggs and tadpoles are exposed to high risks of mortality by pond desiccation. P. andinum reproductive effort may be concentrated into short periods following seasonal heavy rains when toads enter ponds to breed.
Research on the morphological variability of the occlusal surface of M1 talonid in the red foxVulpes vulpes (Linnaeus, 1758) in the Holarctic has been carried out on 2271 specimens originating from 42 populations. The Nearctic was represented by 666 specimens belonging to 13 populations, whereas Palearctic was represented by 1605 specimens from 29 populations. Analyses of the developmental level and formation of cristids between the hypoconid and entoconid allowed the differentiation of 34 shape variants of the occlusal surface of the talonid in the red fox. Because of the complicated variation of cristids, 34 variants were assigned to 5 morphotypes of group P. In the Palearctic and Nearctic a significant geographic variation occurred of P morphotypes and their variants. Primitive variants of the talonid structure on M1 are predominant in populations from the south of the Asian range of the red fox, while more progressive characters of the occlusal surface of the lower carnassial are typical of the northern and centrally located red fox populations in the Palearctic and Nearctic. The geographic differentiation is probably connected with different Pleistocene histories of particular populations.
Gametoclonal variation among anther culture-derived plants of three barley genotypes was estimated on the basis of cytological analysis (DH1, DH2 generation), observation of morphological variants (DH2, DH3) and chlorophyll mutation test (DH2, DH3). Individual head rows were grown in the field to detect possible chimeric structure of regenerants and to assess the number of variants and mutations in each line. Spontaneously doubled plants were the most frequent class (70%) among regenerants and almost 90% of them were completely fertile. There was a difference in proportion of haploids produced by different genotypes, but the highest frequency observed did not exceed 21%. The remaining regenerants were tetraploid, and contained chromosomal mutations or chimeras. In total, there were about 15% of polyploids and plants carrying chromosomal aberrations (translocations, inversions) among DH1 individuals. The changes in chromosome number and structure were the main source of observed variation. The level of gene mutation induced in vitro was relatively low. No more than 1% of microspore-derived plants expressed visible morphological changes in DH2 progeny. Only two morphological variants derived from the Bruce cultivar proved to be homozygous mutants (dwarf type) stable up the to third generation. The frequency of DH plants carrying chlorophyll mutation was 5.8%, but most of them (82%) were chimeric and had only a small mutation sector. The level of gametoclonal variation depended on the donor plant genotype. The highest proportion of variants and mutations was observed among DH plants derived from the Bruce cultivar, while the lowest was recorded among plants regenerated from anther culture of the doubled haploid line H930-36. Mechanisms leading to the observed variation and implications resulting from the presented experiments concerning implementation of anther culture in barley breeding were discussed. It was concluded that this method resulted in a high frequency of spontaneous doubling, a low frequency of genetic changes, and being less time and effort-consuming than the ’Bulbosum’ technique, can be applied to most barley breeding programs.
This study examines morphological variation in the crania (n = 70) of eight cervid species from Argentina. Forty 3-dimensional landmarks were acquired on each adult cervid cranium. The data were analysed using Morphologika software. The co-ordinates were registered and scaled to remove size differences by Procrustes analysis, and then principal components analysis was applied to examine shape variation. Shape variation associated with each principal component can be visualised in the program. The first principal component correlates strongly with the centroid size of the crania and also with the body mass and height of each species. The larger species were distinguished by relatively longer snouts and relatively smaller brains. The smallerMazama andPudu species cluster closely on the first as well as the other principal components. Among the larger species, the twoHippocamelus species, which live at higher altitudes, were clearly distinguished from the lowland species,Ozotoceros bezoarticus andBlastocerus dichotomus, on the basis of cranial flexion and the orientation of the occipital region. FinallyO. bezoarticus andB. dichotomus were compared directly and small differences were noted in the orbital region. The shape data was used to produce a distance matrix and a phenogram, which we relate to some of currently accepted phylogenetic relationships of this group of cervids.
The frequency of occurrence of abnormal, three- (or more) needle dwarf shoots of most southern and central European two-needle pine (Pinus) species were studied. No specimens with more than two-needle dwarf shoots were found in a population of P. nigra Arnold subsp. salzmannii (Dunal) Franco from the Iberian Peninsula and in two populations of P. uliginosa Neumann from the Sudeten Mountains in Central Europe. Single specimens were found within one population of P. pinaster Aiton from the Iberian Peninsula and among six populations of P. sylvestris L. from the Iberian Peninsula and Central Europe. Abnormal dwarf shoots mostly with three, but also four, five or six needles were found among 24 of 25 surveyed populations of P. mugo Turra and P. uncinata Ramond. The average frequency of specimens with at least one three-needle dwarf shoot was 24% for P. mugo and 20% for P. uncinata. The frequencies of occurrence varied significantly among studied populations and were highest in samples collected from the upper elevational range limits of the species in the mountains and near the northern limits of their ranges. The frequency of abnormal dwarf shoots in the same populations was significantly high in 2-3 consecutive years. Needles from three-needle dwarf shoots were not significantly shorter than those of two-needle shoots.
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