Iva Hodálová

Diploid and Tetraploid Cytotypes of Centaurea stoebe (Asteraceae) in Central Europe: Morphological Differentiation and Cytotype Distribution Patterns

The taxomically critical species Centaurea stoebe is represented in Central Europe by a diploid (2n = 18) and a tetraploid (2n = 36) cytotype. Their morphological differentiation and taxonomic treatment is still controversial. Karyological (chromosome numbers and flow cytometric measurements) and multivariate morphometric analyses were used here to address cytotype distribution patterns and their morphological differentiation. Material from 38 localities (771 individuals) in Slovakia, Hungary and Austria, including type localities of the names traditionally applied to the different cytotypes, was sampled and evaluated using both morphometric and karyological approaches. The morphological tendency towards cytotype differentiation is evident only at a population level, and is blurred at the level of individual plants. Diploid populations prevail in the area studied, as well as throughout Europe; mixed-cytotype populations were also found. The present data, namely the weak morphological distinction, largely sympatric occurrence of the cytotypes, and the existence of mixed-cytotype populations, favour taxonomic treatment as a single species, without recognition of infraspecific units.

Intraspecific Variation in Viola suavis in Europe: Parallel Evolution of White-flowered Morphotypes

BACKGROUND AND AIMS Viola species are commonly grown for their ornamental flowers, but their evolutionary history and taxonomy are often complicated and have been poorly explored so far. This is a study of the polymorphic, typically blue-flowered species Viola suavis, concentrating on the white-flowered populations of uncertain taxonomic assignment that occur in Spain and central and south-eastern Europe. The aim was to resolve their origin and taxonomic status and to study the intraspecific structure and (post)glacial history of this species. METHODS Viola suavis and five close relatives were sampled from multiple locations and subjected to molecular (AFLP, sequencing of nrDNA ITS) and morphometric analyses. Data on ploidy level and pollen fertility were also obtained, to address an assumed hybrid origin of the white-flowered populations. KEY RESULTS In V. suavis a strong intraspecific genetic split into two groups was observed, indicating that there has been a long-term isolation and survival in distinct glacial refugia. The white-flowered populations could be placed within the variation range of this species, and it is clear that they evolved independently in two distant areas. Their parallel evolution is supported by both morphological and genetic differentiation. The strongly reduced genetic variation and absence of unique AFLP fragments suggest their derived status and origin from the typical, blue-flowered populations. CONCLUSIONS These results suggest that intraspecific variation in V. suavis has been largely shaped by population isolations during the last glaciation and subsequent recolonizations, although cultivation and vegetative spread by humans have affected the present picture as well.

Multivariate analysis of theSenecio nemorensis group (Compositae) in the Carpathians with a new species from the East Carpathians

Six species and subspecies of theS. nemorensis group from the Carpathians are recognized here, based on morphometric analyses (cluster and discriminant analyses). A new speciesS. ucranicusHodálová and a new hybridS. ×dominiiHodálová=S. germanicusWallr.×S. ucranicusHodálová, occurring in the East Carpathians and the eastern part of the South Carpathians, are described. The vicarious nature ofS. hercynicusHerborg subsp.hercynicus, S. dacicusHodálová etMarhold andS. ucranicusHodálová in the Carpathians is documented. A key to theS. nemorensis group in the Carpathians as well as toS. nemorensis L. s. str. is presented.

Genetic and morphological variation in Viola suavis s.l. (Violaceae) in the western Balkan Peninsula: two endemic subspecies revealed

The Balkan Peninsula, with many endemic species, is known as one of the most important speciation and diversification centres in Europe. Here, we present a study of the western Balkan populations of the polymorphic European species, V. suavis s.l., which have been reported under the name V. adriatica, but their taxonomic status and position within the genus have remained uncertain. Viola suavis s.l. and nine close relatives sampled across Europe were subjected to molecular (sequencing of nuclear ribosomal internal transcribed spacers and amplified fragment length polymorphism), karyological and morphometric analyses. Our results revealed the presence of four allopatric, genetically and morphologically differentiated lineages within V. suavis s.l. in Europe, which are suggested here to be recognized at the subspecific rank. Populations from the western Balkans were segregated into two distinct entities: (1) those from north-western Croatia correspond to the previously recognized taxon, V. suavis subsp. adriatica and (2) those from southern Dalmatia (southern Croatia, southern Bosnia and Herzegovina, and south-western Montenegro) are described here as V. suavis subsp. austrodalmatica subsp. nov. The other two lineages of V. suavis s.l., which both harbour blue- and white-flowered morphotypes, occur in central and eastern Europe (V. suavis subsp. suavis) and in north-eastern Spain (plants provisionally treated as V. suavis ‘Spain’). The AFLP and morphological data indicate gene flow between the nominate subspecies and V. suavis subsp. adriatica in a few localities. The distribution of the two western Balkan subspecies is discussed and an identification key to the V. suavis subspecies in Europe is presented.

Sympatric populations of Senecio ovatus subsp. ovatus, S. germanicus subsp. germanicus (Compositae) and their hybrid in the Carpathians and the adjacent part of Pannonia: I. Multivariate morphometric study

Summary A multivariate morphometric study of Senecio germanicus subsp. germanicus, Senecio ovatus subsp. ovatus and their hybrid, Senecio × futakii based on 19 population samples, collected throughout the Carpathians in Slovakia, Ukraine and Romania, is presented. Multivariate methods used include principal components analysis, cluster analysis, classificatory and canonical discriminant analysis. As a complementary evidence, the hybrid indices were calculated. In spite of possible problems in classification of certain plants into “pure” types or hybrids, the existence of parental species and hybrids in the area studied was proven.

Morphological Characters Useful for the Delimitation of Taxa Within Viola Subsect. Viola (Violaceae): A Morphometric Study from the West Carpathians

Forty-nine morphological characters were scored or measured on 44 populations (376 individuals) of Viola subsect. Viola from the West Carpathians and adjacent areas (Slovakia, Czech Republic, Austria and Hungary). The presence of six species, namely V. alba (represented by subsp. alba), V. ambigua, V. collina, V. hirta, V. odorata and V. suavis s.l. was revealed based on pollen fertility, cytological and morphometric analyses. The morphological characters traditionally used to delimit taxa within the subsection and those revealed by our study as most reliable are widely discussed. A key for identifying the taxa and most common hybrids of subsection Viola occurring in the West Carpathians is presented. Chromosome counting and flow cytometry were used to determine the ploidy levels of the populations studied. All individuals of V. alba subsp. alba, V. collina, V. hirta and V. odorata were tetraploid, while those of V. ambigua and V. suavis s.l. were octoploid.

Sympatric populations of Senecio ovatus subsp. ovatus, S. germanicus subsp. germanicus (Compositae) and their hybrid in the Carpathians and the adjacent part of Pannonia: II. Synecological differentiation and distribution

Summary A synecological study of two sympatric taxa - S. ovatus subsp. ovatus and S. germanicus subsp. germanicus , based on 49 releyes, made during years 1987-1993 in the Carpathians, is presented. Numerical classification (cluster analysis) and ordination (principal components analysis, PCA), were used. Existing published releves obtained from representative phytocoenological tables from the region studied were compared to the results of the numerical classification and ordination. S. germanicus subsp. germanicus was encountered in the whole Carpathians and prefers sunny or semi-shady mesophilous or subxerophilous places (e.g. natural forest fringes) of the submontane and montane belt. S. ovatus subsp. ovatus and S. × futakii ( S. germanicus subsp. germanicus × S. ovatus subsp. ovatus ) is distributed mainly in the West Carpathians in shady, semi-shady mesophilous or hygrophilous places of the submontane and montane belt.

Chromosome numbers and pollen fertility in the Senecio nemorensis group (Compositae) in the Carpathians

New chromosome numbers for two species from the Senecio nemorensis group: S. dacicus (2n = 40) and S. ucranicus (2n = 40) have been ascertained. The counts for S. germanicusWallr. subsp. germanicus (2n = 40), S. hercynicus Herborg subsp. hercynicus (2n = 40), S. ovatus (P. Gaertn. et al.) Willd. subsp. ovatus (2n = 40) occurring in the Carpathians are also reported. The study confirmed only the known tetraploid chromosome number for the taxa of this group. The pollen fertility ranged from 82.09 to 92.99% in all examined species and subspecies, including their hybrids.

Effect of the Gabčíkovo Waterworks (Slovakia) on riparian floodplain forest ecosystems in the Danube inland delta: vegetation dynamics and trends

Abstract Human alteration of watercourses is global phenomenon that has had significant impacts on local ecosystems and the services they provide. Monitoring of abiotic and biotic changes is essential to mitigating long-lasting effects, and the 23-year dataset from the Gabčíkovo Waterworks provided a rare opportunity to assess the impact of groundwater regimes on vegetation. The main aim of this study was to describe the effect of the Gabčíkovo Waterworks on vegetation structure and species composition of the adjacent riparian floodplain forests over the past 23 years. The results are based on studies of three permanent monitoring plots (PMPs) located in the Danube inland delta – two outside (PMP 1 and 3) and one (PMP 2) fully under the influence of the artificial supply system. Our results demonstrate that the Danube inland delta was negatively affected by the Gabčíkovo construction, particularly for sites outside of the artificial supply system. There was a significant decrease in soil moisture and increase in nitrogen at both external PMPs (1 and 3). Alter soil conditions were accompanied by negative changes in plant species composition demonstrated by decreases in the number of typical floodplain forest species that are characteristic for the alliance Salicion albae and either number or cover of neophytes. These changes resulted in slow degradation of the riparian floodplain forests. Vegetation in the artificially-fed PMP 2 was the most stable in terms of the evaluated parameters, however even this site did still experience negative trends in some site characteristics, including soil moisture fluctuations and the number and cover of neophytes. The artificial supply system is not sufficiently replacing previous natural floods, but in some aspects it helped to decrease the negative effect of the Gabčíkovo Waterworks on softwood floodplain forests in the studied area.

Karyological patterns in the European endemic genus Soldanella L.: Absolute genome size variation uncorrelated with cytotype chromosome numbers

PREMISE OF THE STUDY Detailed knowledge about the karyological diversity of organisms undoubtedly represents one of the crucial steps toward a better understanding of their evolutionary trends and history. We investigated the cytotype and absolute genome size (AGS) patterns in the European mountain-dwelling genus Soldanella (Primulaceae) in light of its geographic distribution and ecological diversification. METHODS Our chromosome number survey was based on 34 newly determined and 125 previously published chromosome counts. AGS was estimated on the basis of propidium iodide (PI) flow cytometry (299 individuals, 110 populations). KEY RESULTS We confirmed the existence of two cytotypes with the same ploidy level, i.e., euploid 2n = 40 and dysploid 2n = 38. The overall infrageneric AGS variation ranged between 2.97 and 3.99 pg (25.6% variation). The 2n = 40 cytotype harbors a modest amount of continuous AGS variation. With regard to its distribution area and ecology, the cytotype is ubiquitous. By contrast, the 2n = 38 cytotype was detected only in six forest-dwelling taxa with AGS variation segregated into three discrete, geographically separated groups. The AGS variation of the 2n = 38 cytotype was strongly correlated with elevation and longitude. CONCLUSIONS Despite the apparent morphological and ecological variation, members of the genus Soldanella have not undergone any pronounced cytotype and AGS diversification during their evolutionary history. The lack of correlation between chromosome numbers and AGS indicates that the evolutionary mechanism behind the origin of the dysploid cytotype 2n = 38 was a chromosomal fusion.