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Orceine-stained metaphase chromosomes of P. commutatum . ( a ) Point Reyes, U.S.A. (2n=28), ( b ) Beskidy Mountains, Poland (2n=14). Bar = 5 μ m.
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The morphology, karyotype structure and nuclear DNA amount of European and American representatives of alpine cat's-tail Phleum commutatum Gaud. were analysed. The evolutionary relationships within this group of taxa are discussed. It was shown that the American and European tetraploids are both morphologically and karyologically similar to each ot...
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... (Tab. 4). All the examined lines were charac- terised by the occurrence of SAT chromosomes easi- ly distinguishable in the karyotype, as well as by the sporadic occurrence of 1–2 B chromosomes ( Fig. 2). Analysis of C-banded chromosomes gave better insight into the karyotype structure of P. commutatum . In all analysed forms of alpine cat’s-tail, both diploid and tetraploid, C-banding revealed a centromeric type of heterochromatin distribution (Fig. 3). In the karyotypes of tetraploid specimens from California and Sweden examined in this respect, seven groups of chromosomes were distinguished. The only slight chromosome diversity within the majority of the distinguished groups suggests that the chromosome complements of these plants con- sist of four rather similar genomes. However, some detected differences (especially within chromosome groups 2 and 6; Fig. 4) may signify hybrid (allotetraploid) origin or diploidisation after an autotetraploid event. Collective karyotypes (Fig. 5) showed similar distributions of relatively stable heterochromatin segments in the genomes of three analysed forms: P. commutatum [2x] from Poland and P. commutatum [4x] from Sweden and the U.S.A. Such segments occur in close proximity to all centromeres, and two (in diploid plants) or two/three (in tetraploid plants) chromosome ends. The analysed forms differed in total heterochromatin content (stable + polymorphic blocks of heterochromatin). The American tetraploids clearly differed in this respect from their tetraploid relatives from Sweden, and had heterochromatin amounts similar to those of the diploids from Poland (Fig. ...
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The article presents a concise history of systematic studies on taxa included in the section Phleum of the genus Phleum. The authors discuss the results of cytotaxonomic studies within the section which have been conducted so far and their importance for studies of phylogeny of particular species. It is suggested that the section should be divided...
The paper presents conventional and C-band karyotype structure of Phleum arenarium L. – an annual representative of the Chilochloa section, which grows on coastal sand dunes. Two forms of this species were examined: from Castricum in Holland and from Kent in England. The observed morphological differences between the two forms, which suggest differ...
The authors analysed selected morphological features, the structure of conventional and banded karyotypes and the amount of nuclear DNA in Phleum paniculatum Huds. from the Chilochloa section. The examined specimens came from Afghanistan. The studied population pos-sessed tetraploid chromosome number 2n = 28, which had been observed in this species...
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... Glume apex ends either in a conspicuous awn F) or in a minute mucro ( Figure 1E) so that it appears awnless. The awn may be as long as the glume body or longer ( Figure 1A) or much shorter (Figure 1C,D,6); the observed variation in awn length corresponds closely with that illustrated by Kováts (1976) and Kula et al. (2006). Based on the wide differences in their length, the hairs on the outer surface of glumes were categorized into two clearly separate groups: (i) long hairs ranging in length from 150 μm to about 1200 μm ( Figure 1A-C), and (ii) short hairs not longer than 20 μm. ...
Conflicting and often cursory taxonomic accounts of the genus Phleum L. (Poaceae: Pooideae) have led to difficulties in discriminating among the taxa. Apart from the two notho-species Phleum × brueggeri and Phleum × viniklarii without any synonyms, more than 250 synonyms are on record for the remaining 16 species and their infra-specific taxa. The limited range of characters used in traditional keys to these taxa greatly reduced their applicability. To overcome these difficulties, the key-generating program suite DELTA was used to construct a conventional key to 15 Phleum species (of which five are represented by two subspecies each), based on 20 gross morphological and anatomical characters systematically compared and recorded from culms, leaves and spike-like panicles. For lack of specimens, Phleum iranicum and the two hybrid species are not included in the key. The characters and their states were so precisely defined that only 13 of them were needed to single out each taxon in the key. Detailed descriptions of all taxa based on the entire range of 20 characters are provided to aid identification.
... Tetraploid wild rice shows gigantism in many plant parts, including the stems, leaves, spikelets, and pollen (Parthasarathy et al. 1935). While there are some differences according to the plant variety, the spikelet lengths of tetraploid plants were longer than those in diploid plants of Phleum commutatum (Kula et al. 2006). Moreover, the seeds of tetraploid perennial ryegrass (Lolium perenne L.) were found to be heavier than those of diploid plants (Smith et al. 2003; Hignight and Rush. ...
Because of its high biomass productivity and nutrient-use efficiency, Miscanthus spp. have emerged as promising bioenergy crops. Polyploidism in Miscanthus species is important because it allows non-native countries to cultivate sterile types, such as triploid M. × giganteus, in order to prevent ecosystem disturbance. Although M. sacchariflorus and M. sinensis are considered to be native to Korea, China, and Japan, accurate information describing the ploidy levels of these species has not yet been well established. To evaluate rough ploidy levels, 215 accessions of Miscanthus species were estimated by relative fluorescence intensities of DAPI-stained nuclei. After evaluation of rough ploidy levels, 20 plants were randomly selected by species and ploidy levels, and ploidy levels were examined by counting chromosomes, estimating propidium iodide-stained DNA content with flow cytometry, and measuring sizes of stomata and caryopsis. Among the 20 plants examined, 3 were diploid and 6 were tetraploid M. sacchariflorus (4.56 ± 0.01 and 8.90 ± 0.14 pg/2C nuclear DNA content, respectively), while 6 were diploid and 3 were triploid M. sinensis (5.40 ± 0.18 and 8.29 ± 0.33 pg/2C nuclear DNA content, respectively). One plant was a putative triploid M. × giganteus having 7.31 pg/2C nuclear DNA content, which was similar to an M. × giganteus plant from Illinois, USA having 7.23 pg/2C nuclear DNA content. We confirmed the occurrence of diploid and tetraploid M. sacchariflorus and M. sinensis plants as well as a putative triploid M. × giganteus native to Korea. Thus, measurement of the size of stomata and caryopsis allowed prediction of ploidy levels in the field and laboratory.
Cynodon dactylon has different ploidy levels. The ‘gigas effect’ in morphoanatomic traits caused by the increase in the genetic material is poorly studied in the species. Thus, the present research aimed at carrying out a quantitative and descriptive study of the leaf epidermis structure in PI291169–04 (2n = 2× = 18); PI477004–26 (2n = 3× = 27); PI291721–22 (2n = 4× = 36); PI289750–10 (2n = 5× = 45) accessions, in order to investigate the consequences of the polyploidy. Adult leaves were fixed in FAA and the paradermal sections obtained through the scraping technique were stained in 5% safranin. The measurements of the stomata characteristics (polar diameters – PD, equatorial diameters – QD, stomatal density – SD, stomatal functionality – SF, and stomatal index – SI) were taken by means of the software ImageJ. For analysis in scanning electron microscopy, leaf fragments were fixed in Karnovsky, dehydrated in an acetone series, subjected to a critical point and covered with gold. Stomata were classified as paracytic, dumbbell-shaped and partially covered by papillae. Tector trichomes were classified as uniseriate with pointed tips. In general, as ploidy level increased, there was an increase in stomata dimension and a decrease in SD. Diploid and triploid accessions were easily differentiated in relation to PD and QD, which makes it an indirect method for determining the variation in ploidy level. The variables SD and SI were not efficient to discriminate the accessions. Leaf epidermis has characteristics that emphasize the effect of polyploidization process and its analysis may be used to screening of genotypes in breeding programs.
The research involved examination of 4 populations of the timothy coming from natural positions on both hemispheres of the globe, classified by the Seed Bank as the alpine timothy. Morphological and cytogenetic analyses did not confirm the systematic status attributed before. All the studied forms might be hybrids between the alpine timothy and meadow timothy; the supposition is supported by a number of similarities between the examined specimens and some experimental hybrids of the timothy recently described. This is one of the first reports regarding the possibility of the occurrence of natural interspecific hybrids within the Phleum section.
Phleum is a complex genus involving diploid, tetraploid, hexaploid and octoploid forms. The domesticated forms of Phleum pratense, known as Timothy, are usually hexaploid. There is now considerable potential to introgress and to resynthesize new forms
using wild relatives from other ploidy levels of the section Phleum using the knowledge gained about their relationships from molecular studies. Germplasm of many of these forms is under serious
threat from habitat degradation and climate warming. Unfortunately many of these forms, particularly those from the Mediterranean
and North Africa, are absent from genebanks and their collection for storage in ex situ genebanks is essential.
The relationship among members of the subgenus Phleum was determined using nuclear ribosomal ITS and chloroplast trnL intron DNA sequences. This subgenus is derived from a progenitor of the diploid Phleum alpinum subsp. rhaeticum. The relationships provide evidence of migration, hybridization, polyploidy and speciation associated with historical glaciations.
The subgenus Phleum represents one enormous germplasm pool for breeders and it should now be possible to re-synthesize hexaploid pratense from a wider range of diploid forms than occurred historically. This requires the urgent collection of genetic resources
from the centers of diversity within glacial refugia as these resources are almost entirely absent from genebanks.
Background and Aims The amount of DNA in an unreplicated gametic chromosome complement is known as the C-value and is a key biodiversity character
of fundamental significance with many practical and predictive uses. Since 1976, Bennett and colleagues have assembled eight
compilations of angiosperm C-values for reference purposes and subsequently these have been pooled into the Angiosperm DNA
C-values Database (http://data.kew.org/cvalues/). Since the last compilation was published in 2005, a large amount of data
on angiosperm genome size has been published. It is therefore timely to bring these data together into a ninth compilation
of DNA amounts.
