Chromosome Numbers in Three Asteraceae Tribes from Inner Mongolia (China), with Genome Size Data for Cardueae

Chromosome counts are reported for 15 species of the family Asteraceae from Inner Mongolia (People’s Republic of China). This study includes representatives of the tribes Anthemideae (Artemisia, Chrysanthemum, Filifolium, Hippolytia and Neopallasia), Astereae (Heteropappus) and Cardueae (Echinops and Olgaea). The significance of the chromosome counts is discussed for each species. Within the Anthemideae, chromosome counts for Hippolytia alashanensis (2n?=?36) and the tetraploid level of Artemisia eriopoda (2n?=?36) are reported for the first time. The chromosome number of Heteropappus altaicus (Astereae) agrees with previous reports of one (4x) of the two ploidy levels reported for this taxon. As a complement to the karyological data, genome size of the Cardueae representatives was assessed using flow cytometry. Within this tribe, Echinops gmelini (2n?=?26) and its sister taxon E. acantholepis (2n?=?14) show strongly divergent karyological patterns of difficult interpretation, whereas the count of E. przewalskyi (2n?=?32), assigned here for the first time, coincides with those of its close relatives. In Olgaea tangutica, the chromosome count (2n?=?24) and genome size (2C?=?3.01 pg) given here are the first reports for both the species and the genus.     

Geographical Distribution of Diploid and Tetraploid Cytotypes of Thymus sect. Mastichina (Lamiaceae) in the Iberian Peninsula, Genome Size and Evolutionary Implications

The occurrence of diploid and tetraploid cytotypes in Thymus section Mastichina (Lamiaceae) was investigated by chromosome counting and flow cytometric measurements of DNA content. To cover the entire native distribution of the section across the Iberian Peninsula, plant material was sampled from 29 populations, representing all three taxa (Thymus albicans, T. mastichina subsp. mastichina and T. mastichina subsp. donyanae). We provide first estimates of genome size for taxa of this section. Analyses revealed the existence of new cytotypes in T. mastichina subsp. mastichina (2n?=?2x?=?28, 30) and confirmed the existence of previous ones (2n?=?4x?=?56, 58, 60). We also confirmed the presence of exclusively diploid cytotypes (2n?=?2x?=?30) in the southwestern Iberian endemics T. albicans and T. mastichina subsp. donyanae. We conclude that the southwestern Iberian Peninsula acted as a Pleistocene glacial refugium that may have permitted speciation processes within this section. Several hypotheses concerning these processes and the origin and distribution of the studied taxa are discussed.     

Genome size and ploidy levels in highly fragmented habitats: the case of western Mediterranean Juniperus (Cupressaceae) with special emphasis on J. thurifera L.

Mediterranean junipers are of special ecological importance as key components of resource islands in semi-arid mountain ecosystems of the Mediterranean basin. The fragmentation of their habitat, which was primarily natural and driven by climatic drought conditions, is currently being aggravated by anthropogenic pressure. In the framework of this concern, the present work aims to contribute establishing a genomic profile of Juniperus in its western Mediterranean range, with a special emphasis placed on J. thurifera. DNA contents were assessed by flow cytometry in 43 populations of nine taxa within their Mediterranean range (first reports for J. navicularis, J. thurifera subsp. africana and J. thurifera subsp. thurifera). Chromosome numbers were determined by orcein staining in eight taxa (first counts for J. oxycedrus subsp. badia, J. phoenicea subsp. phoenicea, J. phoenicea subsp. turbinata, of 2n?=?2x?=?22, and for J. thurifera subsp. thurifera, of 2n?=?4x?=?44). Tetraploid cytotypes have been the only ones found in the 19 populations of J. thurifera studied, this being the first report of a Juniperus species exclusively polyploid. In J. thurifera, C-value does not respond to habitat fragmentation, in the same way that genetic diversity within populations was previously shown to be unaltered, suggesting that this factor has not had, at least to date, a significant impact on populations at genomic and genetic levels. Habitat fragmentation leads to deeply age-biased populations with a male-biased imbalanced sex ratio (lack of females), indicating an urgent need to improve regeneration within the populations of this species.     

Annotated chromosome counts of Czechoslovak plants (16–30) (Materials for “Flóra ČSSR”—2)

Chromosome counts of the following 15 taxa are given:Eupatorium cannabinum, Gypsophila fastigiata, Helianthemum grandiflorum subsp.obscurum, Helictotrichon desertorum subsp.basalticum, Impatiens parviflora, Inula hirta, Jurinea mollis, Kernera saxatilis, Lembotropis nigricans subsp.nigricans, Malva alcea subsp.excisa, Myosotis nemorosa, Otites pseudotites subsp.cuneifolia, Plantago atrata subsp.carpatica, P. atrata subsp.sudetica, Poa badensis. The chromosome numbers ofHelictotrichon desertorum (as subsp.basalticum) andPlantago atrata subsp.sudetica are given for the first time. Chromosome numbers differing from those previously known were found inJurinea mollis (2n=34 as compared to 2n=30) andKernera saxatilis (2n=14 as compared to 2n=16).Rhodax Spach (=Helianthemum L. p. p.) andOtites Adans. (=Silene L. p. p.) are considered as separate genera. Remarks on taxonomy, nomenclature and chorology are given for most of the taxa.     

Echinops sahyadricus sp. nov. (Asteraceae: Cardueae), from the northern Western Ghats,Maharashtra, India

The new species Echinops sahyadricus is discovered and described from northern Western Ghats, India. It is endemic to the Maharashtra state and probably restricted to few high mountain peaks in Western Maharashtra. The new species is distinguished from the related E. echinatus by adaxially glabrous to sparsely elgandular hairy leaf surfaces, larger non-cornigerous synflorescences up to 9 cm in diameter and numerous (19–24) glabrous phyllaries up to 27 mm long. An identification key to all Indian taxa of Echinops, illustration and colour plates are provided.     

Meiotic configuration and chromosome number in some Iranian species of Elymus L. and Agropyron Gaertner (Poaceae: Triticeae)

Chromosome numbers and analyses of meiotic metaphase I are reported for the following taxa: Agropyron cristatum subsp. incanum (2n= 42), A. cristatum subsp. pecttnatum (2n=28 – 33), Elymus elongatus subsp. ponticus (2n= 69, 70), E. hispidus var. hispidus (2n= 41 43), var. podperae (2n= 42) and var. villosus (2n= 41, 42), E. libanoticus (2n= 14), E. pertenuis (2n= 28, 28+1B), E. repens (2n= 42), E. transhyrcanus (2n= 40–42), E. hispidus var. villosus x E. cf. repens (2n= 42). Chromosome numbers only are reported for the following taxa: E. gentri (2n= 41, 42), E. nodosus subsp. dorudicus (2n= 28), and E. elongatiformis (2n= 56, 57). The haploid genomic constitution SP is reported for Elymus pertenuis. Variable chromosome numbers (2n= 28–32) were observed in the meiotic metaphase I within single anthers of Agropyron cristatum subsp. pectinatum, and the supernumerary chromosomes in this taxon are assumed to have originated from crosses with hexaploids. Partial elimination of these supernumerary chromosomes probably occurs during archesporial mitotic divisions or at an early stage in the meiotic cycle. A hybrid, morphologically intermediate between E. hispidus and E. repens, was obtained from a seed of E. hispidus collected in the field. The meiotic metaphase I configuration in this E. hispidus hybrid suggests that the pollen parent may itself be a hybrid or hybrid derivative of E. repens x E. hispidus.     

Karyotype variability in species of the genus Zephyranthes Herb. (Amaryllidaceae�CHippeastreae)

In this work, the cytotaxonomic implications of the chromosomal characterization of cultivated and native Zephyranthes species described in northeastern Brazil were studied. All individuals had karyotype formed by a set of metacentric chromosomes, in addition to submetacentric and acrocentric chromosomes. In Zephyranthes robusta, 2n?=?12 was observed and karyotype with formula?4M?+?2SM in somatic cells, representing the most symmetric karyotype among the investigated species. Z.?sylvatica showed three different chromosome complement numbers: 2n?=?12 with formula?1M?+?5SM, 2n?=?12?+?1B with 1M?+?5SM?+?(1B), and 2n?=?18 formed by cracks. The cultivated species Z.?rosea Lindl. presented 2n?=?24 with 4M?+?7SM?+?1A, however Z.?grandiflora Lindl. showed the same chromosome number with 2M?+?5SM?+?5A. Zephyranthes aff. rosea Lindl. presented 2n?=?25 with one small metacentric forming a crack in the fourth metacentric pair. Z.?brachyandra has 2n?=?24?+?(1B) and formula?4M?+?3SM?+?5A?+?(1B). Z.?candida Herb. presented 2n?=?38 and karyotype formula?9M?+?10SM. In Habranthus itaobinus numerical variation was observed, with the majority of populations showing a chromosome complement composed of 2n?=?44?+?1B with 5M?+?12SM?+?5A?+?(1B), or 2n?=?44?+?3B in a single population. Mechanisms involved in the formation of these karyotypes from chromosomal imbalance data are discussed. Taken together, data from this study only partially confirm previous counts for epithets and further enhance the cytological variability data previously reported for the genus.     

Chromosome number and ploidy level of some South American species of Schizachyrium (Poaceae, Andropogoneae)

Chromosome numbers are reported here for 53 accessions belonging to 13 taxa of the genus Schizachyrium. The chromosome counts for the following seven species are recorded here for the first time: S. bimucronatum (2n?=?20), S. gracilipes (2n?=?20), S. hatschbachii (2n?=?20), S. lactiflorum (2n?=?20), S. plumigerum (2n?=?20), S. salzmannii (2n?=?20; 2n?=?40) and S. spicatum (2n?=?20). Counts differing from those previously reported are given for two species: S. scabriflorum (2n?=?20 and 80) and S. tenerum (2n?=?40). Most of the analyzed species of this genus are diploids. The occurrence of polyploidy in S. glaziovii, S. lactiflorum, S. salzmanni, S. scabriflorum and S. tenerum is reported here for the first time. Data on chromosome numbers and ploidy levels are discussed in relation to the taxonomy and evolution of the genus.     

Chromosome numbers in Great Plains species of Penstemon (Scrophulariaceae)

Chromosome numbers are reported for 79 populations ofPenstemon representing 20 species. All but two species counted here are diploids. First counts are reported for seven taxa, all asn=8 or 2n=16.     

Chromosome number, male meiosis and pollen fertility in selected angiosperms of the cold deserts of Lahaul-Spiti and adjoining areas (Himachal Pradesh, India)

In this study the exact chromosome number, detailed meiotic behavior in pollen mother cells and pollen viability were investigated, which can contribute to a better understanding of the cytological evolution of the species growing in the cold deserts of Lahaul-Spiti (Himachal Pradesh, India). This study is the first such comprehensive attempt to explore the region chromosomally. Chromosome number, meiotic behavior and pollen fertility were analyzed in 301 accessions of 140 species of Polypetalae. Chromosome counts in 14 species are the first ever records, viz., Aquilegia pubiflora (n?=?7), Corydalis govaniana (n?=?8), C. thyrsiflora (n?=?8), Hedysarum astragaloides (n?=?7), H. microcalyx (n?=?7), Oxytropis thomsoni (n?=?8), Rhodiola tibetica (n?=?10), R. wallichianum (n?=?16), Rosularia alpestris (n?=?14), Epilobium chitralense (n?=?18), E. leiospermum (n?=?18), Heracleum brunonis (2n?=?33), H. thomsonii (n?=?11) and Pleurospermum govanianum (n?=?9). New intraspecific diploid or polyploid cytotypes have been recorded in 13 species. The species of these cold deserts are quite active in evolution, depicting heterogeneity in chromosome number involving polyploidy, 51 species (36.43%) and/or aneuploidy (37 species). Various meiotic abnormalities were observed in the majority of the species, causing pollen sterility and pollen grains of variable sizes. We are of the opinion that harsh climatic conditions have caused various meiotic abnormalities in the majority of the plants, which has affected the genetic constitution and viability of male gametes.     

Genetic diversity and relationships in Solanum subg. Archaesolanum (Solanaceae) based on RAPD and chloroplast PCR-RFLP analyses

The subgenus Archaesolanum is a group composed of eight species with a characteristic chromosome number based on n?=?x?=?23 and an area restricted to the South Pacific. This subgenus is an isolated group of Solanum for which extensive information about phylogenetic relationships based on molecular genetic methods is lacking. This study represents an approach to analyze genetic relationships within this group. In this context, seven species were examined using random amplified polymorphic DNA (RAPD) markers. In further analysis, the amplification products of two chloroplast regions (trnS-trnG and rbcL) were studied with polymerase chain reaction (PCR) restriction fragment length polymorphism (RFLP) method. Screening for the presence of unique mitochondrial rearrangements was also carried out using universal mitochondrial primers for the detection of fragment length polymorphisms. We identified two major groups within the subgenus; one was composed of the members of ser. Avicularia and Laciniata, while the other was formed by species belonging to ser. Similia. It is suggested that the taxonomic status of series within the Archaesolanum clade should be revised. The hybrid origin of S.?laciniatum was also tested, and two hypotheses regarding its phylogeny are assumed.     

A first approach to the molecular phylogeny of the genusEchinops (Asteraceae): Sectional delimitation and relationships with the genusAcantholepis

A first attempt to establish the phylogeny of the generaEchinops andAcantholepis has been carried out using the analysis of the internal transcribed spacers (ITS) sequences of the nuclear ribosomal DNA including 30Echinops species and the only species of the monotypicAcantholepis. The results of this analysis are discussed in the light of morphological and cytogenetic characters. The genusAcantholepis is placed in a robust clade withEchinops nanus, and together they appear in a basal position to other members ofEchinops. The ITS phylogeny and several other characters, such as chromosome number and nuclear DNA amount, do not agree with the sections currently recognized withinEchinops. Some groups are defined in the present approach, but further studies are necessary to reach a complete, stable and natural infrageneric classification of this genus.     

Chromosome numbers in the genus Mimosa L.: cytotaxonomic and evolutionary implications

Chromosome numbers were determined for 125 accessions of 92 taxa of Mimosa from all five of Barneby??s (Mem New York Bot Gard 65:1?C835, 1991) taxonomic sections. For 69 species, 1 subspecies and 8 varieties, chromosome numbers are presented for the first time, for 6 species and 1 variety previously published data have been confirmed and for 3 species and 2 varieties different numbers were found. Results show that 74% of the accessions were diploid (2n?=?2x?=?26) and 26% polyploid, these mostly tetraploid (2n?=?4x?=?52) but with two triploid (2n?=?3x?=?39). These results double the number of Mimosa species for which the chromosome count is known from less than 10% previously reported to more than 20%, representing an important advance in the cytotaxonomy of this legume genus. These results together with literature data show that ca. 78% of Mimosa species are diploid. Polyploids are present in most of the taxonomic sections and in different lineages across the genus. No particular chromosome number is restricted to a given section or lineage. A possible relation between geography, species distribution, polyploidy and invasiveness was detected, however, further studies based on more accessions, especially from higher latitudes, are required before firm conclusions can be drawn.     

Genetic diversity and structure of a rare endemic cactus and an assessment of its genetic relationship with a more common congener

Endemic, obligate outcrossing plant species with narrow geographic distributions and disjunct populations are prone to loss of genetic diversity. Simultaneously, delineating clear species boundaries is important for targeted conservation efforts. The rare and endemic cactus, Sclerocactus brevihamatus subsp. tobuschii (SBT), has a parapatric relationship with Sclerocactus brevihamatus subsp. brevihamatus (SBB) but genetic distance between the two taxa is unknown. We: (1) developed taxon-specific polymorphic microsatellites, (2) assessed genetic diversity within and among nine populations of SBT, and within one population of SBB, and (3) estimated the genetic relationship between the two subspecies. Within-population genetic diversity of SBT was moderate to high (mean H_o?=?0.37; mean H_e?=?0.59). Indirect estimate of inbreeding corrected for null alleles (F_is-INEst) was low for SBT, ranging from 0.03 to 0.14 (mean F_is-INEst?=?0.07). Genetic differentiation among populations of SBT was low based on F_st (0.08) and AMOVA (Ф_PT?=?0.10). Lack of genetic and spatial correlation in SBT populations coupled with the presence of private alleles and bottleneck events in several populations suggests that reproductive isolation is occurring but that sufficient time may not have yet passed to manifest strong differentiation. Cluster analyses segregated the 10 populations into three distinct groups, and separated SBB genotypes clearly. Results suggest that while hybridization between the two subspecies may occur, SBT is clearly differentiated genetically from SBB to retain its current taxonomic status.     

Karyological relationships among some South American species of Solanum (Solanaceae) based on fluorochrome banding and nuclear DNA amount

Fluorescent chromosome banding and measurements of nuclear DNA content by image cytometry of Feulgen-stained cells were performed in one sample each of eight diploid (2n?=?24) species of Solanum: S.?endoadenium, S.?argentinum, S.?pseudocapsicum, S.?atropurpureum, S.?elaeagnifolium, S.?sisymbriifolium, S.?chenopodioides, and S.?palustre. The species studied could be distinguished by heterochromatin amount, banding patterns, and genome size. They exhibited only GC-rich heterochromatin and showed a comparatively low heterochromatin amount (expressed as percentage of haplotype karyotype length), ranging from 2.10 in S.?argentinum to 8.37 in S.?chenopodioides. Genome size displayed significant variation between species, with 1C-values ranging from 0.75?pg (735?Mbp) in S.?palustre to 1.79?pg (1,754?Mbp) in S.?sisymbriifolium. No significant correlation between genome size and heterochromatin amount was observed, but intrachromosomal asymmetry index (A ₁) was negative and significantly correlated with heterochromatin amount. DNA content was positively and significantly correlated with karyotype length. DNA C-value distribution in the genus as well as karyotype affinities and relationships between species are discussed in relation to different infrageneric classifications of Solanum.     

Annotated chromosome counts of czechoslovak plants (31–60) (Materials for “Flóra ČSSR”—3)

Chromosome counts of the following 30 taxa (106 populations) are given:Betonica officinalis (2n=16);Bidens frondosus (2n=48);Calamagrostis arundinacea (2n=28+0–2B);Dianthus carthusianorum subsp.latifolius (2n=30);Festuca gigantea (2n=42, 42+2B);Hypericum perforatum (2n=32);Koeleria macrantha (2n=28);Kohlrauschia prolifera (2n=30);Lilium martagon (2n=24+0–2B);Melica ciliata (2n=18);Poa remota (2n=14);Ranunculus polyanthemos (2n=16);R. sardous subsp.sardous (2n=16);Roegneria canina (2n=28+0–1B);Rudbeckia laciniata (2n=76);Scabiosa canescens (2n=16);Serratula tinctoria (2n=22);Seseli elatum subsp.heterophyllum var.beckii (2n=18);S. hippomarathrum (2n=20);Thlaspicaerulescens caerulescens subsp.tatrense (2n=14);Trifolium alpestre (2n=16);T. avense (2n=14);T. medium (2n=79, 80+0–2B, 82);T. rubens (2n=16);Veronica officinalis subsp. alpestris (2n=36);Vincetoxicum hirundinaria (2n=22);Vulpia bromoides (2n=14);Zerna benekenii (2n=28)Z. monoclada (2n=28+0–8B);Z. ramosa (2n=42). Remarks on taxonomy, nomenclature and chorology for some of these taxa are given.     

Genetic diversity of Cypripedium calceolus in Poland

In this work we assessed the genetic diversity of 32 C.?calceolus populations from Poland. Mean genetic diversity was moderate (P?=?36.4%, A?=?1.58, H _O?=?0.143, F _IS?=?0.059), and seven geographic regions did not differ significantly in their levels of polymorphism (p?>?0.05), although allele frequencies varied greatly. Only four unique alleles were found, at three sites in southern and southeastern Poland. Genetic (P, A) and genotypic diversity parameters (G, G _U) were significantly correlated with population size (p?<?0.001). In the 32 studied populations we separated 422 different multilocus genotypes; none was common to all populations. Overall population differentiation was moderate at 0.137 (p?<?0.001), but we found a significant pattern of isolation by distance for the whole dataset (r ²?=?0.65, p?<?0.001). Our chloroplast DNA (cpDNA) results suggest a single evolutionary lineage and a common origin for all Polish C.?calceolus populations. Information about the genetic health of C.?calceolus populations should be useful in developing conservation strategies.     

Morphological and genetic diversity within Pilosella hoppeana aggr. (Asteraceae) in Italy and taxonomic implications

Morphological variation, ploidy level and genetic diversity have been studied on 10 populations of the Pilosella hoppeana aggr. from the Alps, Abruzzo, Calabria and Sicily. Chromosome counts showed that the plants from Abruzzo and those from Sicily are tetraploid (2n = 36); they are assigned to P. hoppeana subsp. macrantha. The plants from the Alps (P. hoppeana subsp. hoppeana) and those from Calabria are diploid. The Calabrian populations, previously included in P. hoppeana subsp. macrantha, are shown to belong to a separate species, P. leucopsilon. The principal component analysis, based on 25 morphological characters, allowed distinguishing clearly four groups. An allozyme study using 10 enzyme systems revealed 7 polymorphic loci with a total of 20 alleles, some of them exclusive at regional level, others shared between populations showing similar morphological features. The genetic differentiation between populations was relatively high. The obtained dendrogram supports recognition of the morphologically defined taxa.