Chromosome numbers in 19 populations of Tanacetum polycephalum and Tanacetum parthenium from natural resources gene bank, that collected from different regions of Iran, were determined for the first ...time. The samples prepared by using root tips. After pretreatment, fixation, hydrolysis and staining, the microscopic samples prepared by squash method, metaphases were captured using an optical microscope. The best metaphases plates were selected and used for karyotype analyses. In all of populations the basic chromosome number was x=9 and the populations showed two ploidy levels (diploid & tetraploid). The type of the most chromosomes in all of the populations was metacentric (m) and sub-metacentric (sm) and located in 2A and 2B except for T. parthenium (Yazd, Taft) with 5m+3sm+1st karyotype formula and 2C Stebbins classes. In addition, T. polycephalum (Esfahan, Golpayegan) with the highest value of AR and A1 had karyotype heterogeneity, also T. polycephalum (Esfahan, Golpayegan) and T. polycephalum (West-Azerbaijan, Uromeyeh) had the highest value of chromosome length (TL). Detailed karyotype allows us to group the different populations based on Stebbins classes and asymmetry indices.
This study was conducted to investigate the effects of different irrigation
water salinity level on chromosomes and shoots of wheat with three different
ploidy level (diploid, tetraploid and ...hexaploid). Greenhouse experiment
revealed that irrigation water salinity level had significant effects on
shoot dry weight, root dry weight, shoot length and root length (P<0.05).
The effects of ploidy level and cultivar shoot dry weight and root dry
weight were also found to be significant (P<0.05), but the effects on shoot
length and root length were not significant (P>0.05). Negative effects of
salinity on shoot and root were started at 8 dS m-1. Also hexaploid wheat
was more tolerant then tetraploid and diploid wheat to salinity. It was not
determined that possible effects of irrigation water salinity to structure
of chromosomes with current equipment and methods. Cell divisions were
normal, but decreasing cell division rates were observed with increasing
irrigation water salinity levels.
nema
Sexual reproduction in eukaryotes implies a biphasic life cycle with alternating haploid and diploid phases. The nature of the biphasic life cycle varies markedly across taxa, and often either the ...diploid or the haploid phase is predominant. Why some taxa spend a major part of their life cycle as diploids and others as haploids remains a conundrum. Furthermore, ploidy levels may not only vary across life cycle phases but may also differ between males and females. The existence of two life cycle phases and two sexes bears a high potential for antagonistic selection, which in turn may influence the evolution of ploidy levels. We explored the evolution of ploidy levels when selection depends on both ploidy and sex. Our analyses show that antagonistic selection may drive the ploidy levels between males and females apart. In a subsequent step, we explicitly explored the evolution of arrhenotoky (i.e., haploid males and diploid females) in the context of antagonistic selection. Our model shows that selection on arrhenotoky depends on male fitness but evolves regardless of the fitness consequences to females. Overall we provide a plausible explanation for the evolution of sex differences in ploidy levels, a principle that can be extended to any system with asymmetric inheritance.
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The aim of this study was to assess genome size variation and multivariate morphometric analyses to ascertain cytotype distribution patterns and the morphological differentiation within the ...Ranunculus parnassifolius group in the Pyrenees and the Alps. Although divergences in nuclear DNA content among different species within a genus are widely acknowledged, intraspecific variation is still a somewhat controversial issue. Holoploid and monoploid genome sizes (C- and Cx-values) were determined using propidium iodide flow cytometry in 125 plants of R. parnassifolius s.l. distributed across four European countries. Three different DNA ploidy levels were revealed in the study area: diploid (2n ~ 2x, 57.14%), triploid (2n ~ 3x, 1.19%), and tetraploid (2n ~ 4x, 41.67%). The mean population 2C-values ranged from 8.15 pg in diploids to 14.80 pg in tetraploids, representing a ratio of 1 : 1.8. Marked intraspecific/interpopulation differences in nuclear DNA content were found. Diploid populations prevail in the Pyrenees, although tetraploid cytotypes were reported throughout the distribution area. In general, mixed-cytotype populations were not found. The Spearman correlation coefficient did not reveal significant correlations between genome size and altitude, longitude, or latitude. Morphometric analyses and cluster analyses based on genome size variation revealed the presence of three major groups, which exhibited a particular biogeographical pattern. A new cytotype, DNA triploid, was found for the first time. Tetraploid populations showed constant nuclear DNA levels, whereas diploid populations from the Pyrenees, in which introgressive hybridization is suggested as a presumable trigger for genome size variation, did not. Scenarios for the evolution of geographical parthenogenesis in R. parnassifolius s.l. are discussed. Finally, the different levels of effectiveness between plant and animal reference standards are analysed.
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BFBNIB, DOBA, FZAB, GIS, IJS, IZUM, KILJ, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBMB, UILJ, UKNU, UL, UM, UPUK
The aims of this study were to determine the chromosome numbers in hybrid spermatozoa, involved in the production of viable backcross progenies, and to ascertain the chromosome numbers in ...backcrosses. The experiments for obtaining backcrosses were conducted in the Luchegorsk experimental station of the TINRO Centre in 2010. 16 one-year-old backcross hybrids sterlet x (sterlet x kaluga) and 14 one-year-old backcrosses kaluga x (sterlet x kaluga) were karyologically studied by using previously described method. From one to 23 metaphase plates were analyzed from every studied fish. Average chromosome numbers in 14 backcross hybrids sterlet x (sterlet x kaluga) varied from 139 to 157. It means that hybrid males (sterlet x kaluga), participated in their origin, produced spermatozoa with 79-87 chromosomes. Two other backcrosses sterlet x (sterlet x kaluga) had about 178 and 184 chromosomes. Thus, they got 118-124 chromosomes from their fathers. Among backcrosses kaluga x (sterlet x kaluga), 11 specimens had 201-214 chromosomes, and three specimens: 219-223.
Ranunculus parnassifolius is an orophilous plant distributed throughout Central and Southwestern Europe (Alps, Pyrenees and Cantabrian Mountains). Its evolutionary history and taxonomy are often ...complicated, having been little studied before now. The purpose of this article is to present flow cytometry measurements and multivariate morphometric analyses to ascertain cytotype distribution patterns and the morphological differentiation of R. parnassifolius s.l. from calcareous screes in the Northwest of Spain. DNA ploidy level and morphometric analysis were determined for plants of R. parnassifolius s.l. using flow cytometry (112 individuals) and multivariate analysis (152 individuals). Specimens were collected in eight localities in the Northwest of the Iberian Peninsula. Different sample preservation methods (fresh, frozen, and herbarium specimens) were employed as well as the use of various buffers and internal standards, in order to test the reproducibility of DNA flow cytometry. Three ploidy levels were detected in the study area (diploid, tetraploid, and pentaploid), and mixed-cytotype populations were also found. The mean nuclear DNA content of the R. parnassifolius group ranged from 7.43 ± 0.185 to 7.63 ± 0.339 pg/2C in diploids and from 15.09 ± 0.161 to 15.85 ± 0.587 pg/2C in tetraploids. The analysis of the monoploid genome sizes (1Cx) did not reveal a clear difference among cytotypes. These results suggest low intraspecific variation, at least among the populations studied. In addition, a comparison of different DNA reference standards was conducted. A new value for the chicken genome size was used as internal reference standard (2C = 3.14 ± 0.155 pg), with similar results found using both animal and plant standards (Pisum sativum and Solanum lycopersicum). Finally, herbarium vouchers and frozen tissue were proved to be suitable for DNA ploidy level measurements. This study provided a first assessment of C values in the R. parnassifolius group using flow cytometry. The weak morphological distinction of the cytotypes and the existence of mixed-cytotype populations in the Northwest of Spain are reported here for the first time. The different distribution pattern of the two cytotypes is discussed.
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BFBNIB, DOBA, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NLZOH, NMLJ, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UILJ, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Phragmites australis (Cav.) Trin. ex Steud. (common reed) is one of the most widespread plant species in the world. The species has a high phenotypic variation in morphology and life-history traits. ...This high phenotypic variation can be related to variance in chromosome numbers, clonal diversity, plasticity of clones or a combination of these. An overview of our present, still limited, knowledge concerning the amounts, causes and maintenance of genetic diversity in
P. australis is given.
In
P. australis a large range in euploid number has been found (between 3
x–12
x, except for 5
x and 9
x, with
x
=
12). In Europe tetraploids are dominant, whereas octoploids predominate in Asia. Aneuploids also occur regularly in
P. australis, and differences in chromosome numbers have been observed even within clones. Clonal diversity in
P. australis has been studied using allozyme polymorphisms and molecular markers. Both mono- and polyclonal stands are known to exist. A surprisingly high number of clones has been found in European stands. Environmental and genetic factors, which may account for this high clonal diversity, are discussed. In most studies on the occurrence of ecotypes in
P. australis no distinction has been made between plastic and genetic variation. But evidence exists that responses to climate, hydrology and salt have a genetic basis. Until now no attempts have been made to determine which genes or gene complexes are responsible for these different responses.
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Amplified fragment length polymorphism markers were used to assess the genetic relatedness between Dioscorea alata and nine other edible Dioscorea. These species include D. abyssinica Hoch., D. ...bulbifera L., D. cayenensis-rotundata Lamk. et Poir., D. esculenta Burk., D. nummularia Lam., D. pentaphylla L., D. persimilis Prain. et Burk., D. transversa Br. and D. trifida L. Four successive studies were conducted with emphasis on the genetic relationship within D. alata and among species of the Enantiophyllum section from Vanuatu. Study 1 was carried out to select a set of polymorphic primer pairs using 11 combinations and eight species belonging to five distinct sections. The four most polymorphic primer pairs were used in study 2 among six species of the Enantiophyllum section. Study 3 focussed mainly on the genetic relationship among 83 accessions of D. alata, mostly from Vanuatu (78 acc.) but also from Benin, Guadeloupe, New Caledonia and Vietnam. The ploidy level of 53 accessions was determined and results indicated the presence of tetraploid, hexaploid and octoploid cultivars. Study 4, included 35 accessions of D. alata, D. nummularia and D. transversa and was conducted using two primer pairs to verify the taxonomical identity of the cultivars 'langlang', 'maro' and 'netsar' from Vanuatu. The overall results indicated that each accession can be fingerprinted uniquely with AFLP. D. alata is an heterogeneous species which shares a common genetic background with D. nummularia and 'langlang', 'maro' and 'netsar'. UPGMA cluster analysis revealed the existence of three major groups of genotypes within D. alata, each assembling accessions from distant geographical origins and different ploidy levels. The analysis also revealed that 'langlang', 'maro' and 'netsar' clustered together with the cultivar 'wael' (D. transversa) from New Caledonia. Results are discussed in the paper.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Comparison of SB1 and SB3 cell lines in both suspension and callus cultures showed that the latter, which produce much more dark brown pigments, had higher levels of condensed tannins. They also had ...higher total phenolics and flavonoid contents and L-phenylalanine ammonia lyase activity.
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