Search

Polyploidization is pivotal in plant speciation, affecting adaptability, ecological tolerance and specific geographical distribution patterns. While cytotype diversity has been extensively studied in angiosperms and ferns, knowledge in homosporous lycophytes remains very limited. Our study addresses this gap, focusing on the homosporous lycophyte Huperzia selago in Central Europe. The genome size of 1330 individuals from 208 populations were assessed via flow cytometry, revealing five distinct cytotypes (2x, 3x, 4x, 5x, 6x). Challenging chromosome counting using gemmae roots yielded average counts of 140 (2x), 204 (3x), and 262 (4x) chromosomes. The hexaploid genome size (29 pg) approached the upper limits reported for lycophytes. Tetraploids were the most abundant (72.7%), while triploids (21.3%) were less common, while the remaining cytotypes comprised less than 5% of the dataset. Geographical separation of cytotypes was not observed. However, uncommon cytotypes were associated with the Alps and triploids also occured in the highest parts of Western Carpathians. Around 27.3% of populations exhibited multiple cytotypes. Except for atypical diploids, spore abortion differed between even (21.8%) and odd ploidies (65.2%). Microcharacter (stoma, spore) proportions did not linearly correspond with increasing ploidy levels. The high ploidy-level diversity and cytotype coexistence in Central European H. selago match the well documented patterns in ferns and angiosperms. These findings provide valuable insights into lycophyte polyploidy, underscoring the necessity for broader geographical sampling and application of molecular studies to elucidate phylogenetic relationships and taxonomic classifications within the genus Huperzia. [ABSTRACT FROM AUTHOR]

In this contribution, new chromosome data obtained on material collected in Italy are presented. It includes counts from six populations of three taxa within the genus Pulmonaria, two of which are endemic to Italy (P. vallarsae subsp. apennina and P. vallarsae subsp. vallarsae); the other is the widespread European P. officinalis. In addition, two counts from Potentilla detommasii and Stachys thirkei, two eastern Mediterranean species, are also reported. [ABSTRACT FROM AUTHOR]

Twenty-three Caltha palustris accessions and ten C. scaposa accessions have been cytologically investigated using the traditional chromosome tableting technique and flow cytometry(FCM), in order to investigate the evolution of C. palustris and C. scaposa in Caltha of Ranunculaceae. C. palustris was found to be a polyploid complex, which contained tetraploids(2n=4x=32), hexaploids(2n=6x=48), and octoploids(2n=8x=64), and C. scaposa were tetraploids(2n=4x=32)and octoploids(2n=8x=64). Tetraploids were common in C. palustris and C. scaposa, however, any diploids were hardly discovered. This finding may be explained by cytotype adaptive differences to the underlying heterogeneity of environmental factors. Most accessions of C. palustris and C. scaposa were from extreme habitats, such as the alpine mountains in the Qinghai-Tibetan Plateau. Ancestral diploids may have existed in this region during glacial periods and colonized most regions at the end of the glaciation cycles. However, individuals with other ploidy levels may gradually replace diploids, because of their increased fitness in changing environment. Moreover, there were two possible evolutionary colonization routes: one from Gansu to Yunnan, and the other from Tibet to Yunnan of China. Molecular phylogeny have shown that C. scaposa is closely related to C. palustris, the chromosome size of C. scaposa is smaller than that of C. palustris, C. scaposa may be a relatively derived evolutionary taxon. More samples need to be analyzed in the future to better elucidate C. scaposa cytogeography because of only ten accessions. [ABSTRACT FROM AUTHOR]

Premise: Although autopolyploidy is common among dominant Great Plains grasses, the distribution of cytotypes within a given species is typically poorly understood. This study aims to establish the geographic distribution of cytotypes within buffalograss (Buchloë dactyloides) and to assess whether individual cytotypes have differing ecological tolerances. Methods: A range‐wide set of 578 B. dactyloides individuals was obtained through field collecting and sampling from herbarium specimens. The cytotype of each sample was estimated by determining allele numbers at 13 simple sequence repeat loci, a strategy that was assessed by comparing estimated to known cytotype in 79 chromosome‐counted samples. Ecological differentiation between the dominant tetraploid and hexaploid cytotypes was assessed with analyses of macroclimatic variables. Results: Simple sequence repeat variation accurately estimated cytotype in 89% of samples from which a chromosome count had been obtained. Applying this approach to samples of unknown ploidy established that diploids and pentaploids are rare, with the common tetraploid and hexaploid cytotypes generally occurring in sites to the north/west (tetraploid) or south/east (hexaploid) portions of the species range. Both MANOVA and niche modeling approaches identified significant but subtle differences in macroclimatic conditions at the set of locations occupied by these two dominant cytotypes. Conclusions: Incorporating chromosome count vouchers and cytotype‐estimated herbarium records allowed us to perform the largest study of cytotype niche differentiation to date. Buffalograss cytotypes differ greatly in frequency, the common tetraploid and hexaploid cytotypes are non‐randomly distributed, and these two cytotypes are subtly ecologically differentiated. [ABSTRACT FROM AUTHOR]

In this contribution new chromosome data obtained from material collected in Italy are presented. It includes four chromosome counts for the following genera: Bellevalia (Asparagaceae), Genista (Fabaceae), Linaria (Plantaginaceae), and Teucrium (Lamiaceae). [ABSTRACT FROM AUTHOR]

* Premise of the study: Polyploidy--the possession of more than two copies of each chromosome in the nucleus--is common in flowering plants. Polyploid plants can occupy different geographic ranges than their diploid progenitors, but the factors responsible for maintaining these range differences are poorly understood. Polyploidy can have significant physiological consequences, and the present study aims to determine whether previously described physiological differences between cytotypes are correlated with climatic niches and geographic distributions. * Methods: Prior research indicates that tetraploid plants of Chamerion angustifolium (Onagraceae) are more tolerant of drought and less tolerant of freezing than diploids, which suggests that they should occupy a niche that is warmer and drier than that of diploids. We extracted climate data for 134 populations of C. angustifolium classified as pure diploid, pure tetraploid, or mixed-ploidy. We compared climatic conditions between these population categories and generated ecological niche models to compare their geographic distribution with prior qualitative estimates. * Key results: Pure tetraploid populations occupy habitats that are warmer and drier than those of pure diploid populations. Mixed-ploidy populations occur in habitats that are not strictly intermediate between pure diploid and pure tetraploid populations, but are as cold as pure diploid populations and have intermediate soil moisture deficits. Our niche models were similar to previous qualitative estimates of cytotype geographic distribution. * Conclusions: The correspondence between the physiological tolerances of cytotypes, their climatic niches, and their geographic distributions suggests that physiological traits are at least partially responsible for differences in the realized climatic niches of diploid and tetraploid C. angustifolium. [ABSTRACT FROM AUTHOR]

• Background and Aims Karyological variation in the Mediterranean genus Borago and cytogeography of subgenus Buglossites in Corsica, Sardinia and the Tuscan Archipelago were investigated in combination with a molecular phylogenetic analysis aimed at elucidating relationships between subgenera and taxa with different chromosome features.• Methods Karyotype analysis was performed on population samples of B. pygmaea, B. morisiana, B. trabutii and B. officinalis. Phylogenetic analyses were based on ITS1 nrDNA and matK cpDNA sequences.• Key Results Four base numbers were found, x = 6, 8, 9 and 15, and three ploidy levels based on x = 8. In subgenus Buglossites the Sardinian endemic B. morisiana is diploid with 2n = 18, while B. pygmaea includes three allopatric cytotypes with 2n = 30 (Sardinia), 2n = 32 (southern Corsica) and 2n = 48 (central northern Corsica and Capraia). In subgenus Borago, the Moroccan endemic B. trabutii and the widespread B. officinalis have 2n = 12 and 2n = 16, respectively. Molecular data support the monophyly of Borago, while relationships in subgenus Borago remain unclear. Borago trabutii appears as the earliest divergent lineage and is sister to a clade with B. officinalis, B. morisiana and B. pygmaea. Subgenus Buglossites is also monophyletic, but no correspondence between ITS1 phylogeny and B. pygmaea cytotypes occurs.• Conclusions Chromosome variation in Borago is wider than previously known. Two base numbers may represent the ancestral condition in this small genus, x = 6 or x = 8. An increase in chromosome number and karyotype asymmetry, a decrease in chromosome size and heterochromatin content, and the appearance of polyploidy are the most significant karyological changes associated with the divergence of the Buglossites clade. High ITS1 variation in the tetra- and hypotetraploid races of B. pygmaea suggests a multiple origin, while the lower polymorphism of the hexaploid race and its allopatric distribution in the northernmost part of the range is better explained with a single origin via union of unreduced and reduced gametes. [ABSTRACT FROM AUTHOR]

The ploidy level and karyotype of Muscari botryoides (s.l.) samples from Hungary (25 localities) and Romania (1 locality: locus classicus of M. transsilvanicum) were determined. The Romanian sample proved to be diploid (2n=18), while in Hungary both diploid and tetraploid (2n=36) populations occurred. The karyotypes of all diploid populations were similar: 2 pairs of long acrocentric (one of them usually with satellites) + 3 pairs of medium-sized submetacentric-metacentric + 4 pairs of short ± metacentric chromosomes. All diploid populations in Hungary can be identified as M. transsilvanicum. There is no reason to support the taxon M. botryoides subsp. hungaricum because it does not differ from the sample collected at the locus classicus of M. transsilvanicum (Romania, Sibiu-Guşteriţa) in any of the characteristics mentioned in its protologue. Its karyotype also corresponds to that of M. transsilvanicum. Contrary to the former assumptions, the tetraploid M. botryoides is also native to Hungary. The tetraploid karyotype seems to be somewhat of a duplication of the diploid one. Morphological characters used in the identification keys are not suitable for unambiguous separation of the taxa mentioned above, though morphometric analyses revealed some quantitative differences between diploids and tetraploids. Their separation on species level can only be supported by the supposed reproductive barriers caused by different ploidy level and chorology. In Hungary M. transsilvanicum is restricted mostly to the Eupannonian Region, the Mecsek and Villány Mts. M. botryoides does not occur in the Eupannonicum, instead it inhabits the subatlantic hilly W and SW part of Hungary and the Northern Mountain Range. The latter territory (including also the Slovak localities) seems to be the easternmost extension of the area of M. botryoides. [ABSTRACT FROM AUTHOR]

Seven hundred and fourteen individuals of theScilla sinensis(Louriro) Merrill complex were sampled from 21 populations at 19 localities in 10 provinces and two cities of China and investigated cytologically in order to test its cytotype composition and cytogeographical variation still further. Five cytotypes were found (i.e. AA (2n= 16), BB (2n= 18), AABB (2n= 34), AAA (2n= 24), and AABB+9 (2n= 43)). Until now, nine of the 12 cytotypes have been identified on the continent, which indicates that it is an important place for the cytotypic differentiation of the complex. The cytotype AABB+9 is a new record on the continent. AAA was recorded for the second time in this complex. The majority of populations are composed of only one cytotype (AA, BB, or AABB), whereas another four populations consist of more than two cytotypes involving AA, BB, AAA, AABB, and AABB+9. The distribution of BB covers the entire region south to Huai River, whereas AA populations are distributed in Taiwan, Fujian, Hong Kong, and Guangdong and are isolated from its major distribution. The appearance of AABB+9 is possibly evidence for the degeneration of the subglobular bulb type of AABB and the fact that AAA and AAAA exist in the interior border regions of the range of this complex probably suggests that drought is a major factor promoting plant polyploidization. In addition, the mean numbers of B chromosomes per individual, the percentage of individuals with the B chromosome in each population, and the correlation coefficients between the latter and their latitude/longitude were calculated. Generally speaking, the B chromosome number is higher in BB populations compared with AA populations and there is a prominent tendency that the B chromosome content in either AA or BB populations correlates with the latitude and longitude of the populations.(Managing editor: Wei WANG) [ABSTRACT FROM AUTHOR]