SPECIATION AND BASIC CHROMOSOME NUMBER IN THE GENUS CELOSIA

1961 ◽  
Vol 39 (1) ◽  
pp. 45-50 ◽  
Author(s):  
William F. Grant
Keyword(s):  
Chromosome Number ◽  
Somatic Chromosome ◽  
Basic Chromosome Number ◽  
Somatic Chromosome Number ◽  
Basic Chromosome ◽  
Natural Cross

A new allopolyploid species of Celosia, namely, C. whiteii, collected in Malaya and originating from a natural cross between C. argentea L. (2n = 72) and C. cristata L. (2n = 36), has been described and the somatic chromosome number determined as 2n = 108. A somatic chromosome number of 2n = 18 has been determined for another species of Celosia, namely, C. trigyna L. The basic chromosome number for the genus has been determined as nine. Of the four species of Celosia so far studied cytologically, each represents a different level of ploidy, from diploid (2x) to dodecaploid (12x).

A CYTOLOGICAL STUDY OF THE GENUS POA L.

1937 ◽  
Vol 15c (6) ◽  
pp. 281-297 ◽  
Author(s):  
J. M. Armstrong
Keyword(s):  
Chromosome Number ◽  
Chromosome Numbers ◽  
High Frequency ◽  
Somatic Chromosome ◽  
Poa Pratensis ◽  
Basic Chromosome Number ◽  
Somatic Chromosome Number ◽  
Indigenous Plants ◽  
Somatic Chromosome Numbers ◽  
Fibre Attachment

The somatic chromosome numbers of 20 species of Poa were determined. The basic chromosome number for the genus was found to be seven. The species arranged themselves in a polyploid series from diploid to dodecaploid, tetraploids and hexaploids being the most numerous. Three aneuploid species possessed chromosome numbers suggestive of a nonaploid origin. Polymorphism was found to be present in P. compressa L., P. palustris L. and P. nemoralis L. All species examined conformed to the long chromosome type common to the subfamily, Pooideae. The spindle fibre attachment for the chromosomes in the various species ideograms was found to be regularly median or submedian.The chromosome variability and the mode of seed production were examined in Poa pratensis L., using selected, uniform strains, indigenous plants and plants grown from commercial seed. The somatic chromosome number was found to range from 50 to 87 ± 1, 10 of the 19 plants examined possessing aneuploid numbers. The selected strains possessed the same chromosome number for both plants examined, while in the other material the number was variable. A study of meiosis in the P.M.C. showed the selected strains to vary from regular behavior to an irregularity of 3.9 unpaired univalents per cell. All strains possessed large percentages of morphologically good pollen which germinated actively on the stigmas. Reduction was observed in the E.M.C. of the selected strains and a study of the course of embryological development showed no irregularities which might lead to aposporous reproduction. A high frequency of polyembryony was observed which was correlated to the degree of irregularity at meiosis. A theory is advanced to explain how constant aneuploid numbers may be maintained in sexually reproduced strains.

Chromosome number and size variations in the Australian Salicornioideae (Chenopodiaceae)—evidence of polyploidisation

2003 ◽  
Vol 51 (4) ◽  
pp. 441 ◽  
Author(s):  
K. A. Shepherd ◽  
G. Yan
Keyword(s):  
Chromosome Number ◽  
Phenotypic Variation ◽  
Somatic Chromosome ◽  
Basic Chromosome Number ◽  
Genome Length ◽  
Chromosome Counts ◽  
Ploidy Levels ◽  
Basic Chromosome ◽  
Endemic Genus ◽  
Australian Species

New somatic chromosome counts were recorded from 27 accessions representing 21 Australian species across six genera, Halosarcia Wils., Pachycornia Hook.f., Sarcocornia Scott, Sclerostegia Wils., Tecticornia Hook.f. and Tegicornia Wils., in the subfamily Salicornioideae Ulbr. (Chenopodiaceae Venten.). The results indicated that the Australian Salicornioideae have a basic chromosome number of x = 9, congruent with other members of the Chenopodiaceae. Polyploidy is evident, particularly in the largest genus Halosarcia, ranging from diploid to hexaploid (2x = 18, 27, 36 and 54). With the exception of Pachycornia triandra (F.Muell.) Black, the chromosomes observed were 1.11–3.85 μm in length, with a total genome length of the haploid set of 13.82–23.16�μm. P. triandra had considerably larger chromosomes (3.09–5.57 μm) with a total genome length of the haploid set of 36.93 μm.Intraspecific ploidy variation occurs in the mostly endemic genus Halosarcia, which is the largest genus in the subfamily. Diploid, triploid and tetraploid ploidy levels were detected in H. indica (Willd.) subsp. bidens (Nees) Wils. sampled from separate populations and two ploidy levels were recorded in seedlings germinated from individual H. leptoclada Wils. and H. pterygosperma (Black) Wils. adults. The presence of polyploidy in Halosarcia may provide a mechanism that fosters diversity and phenotypic variation.

scholarly journals Karyotype and genome size variation in white-flowered Eranthis sect. Shibateranthis (Ranunculaceae)

PhytoKeys ◽  
2021 ◽  
Vol 187 ◽  
pp. 207-227
Author(s):  
Elizaveta Yu. Mitrenina ◽  
Andrey S. Erst ◽  
Lorenzo Peruzzi ◽  
Mikhail V. Skaptsov ◽  
Hiroshi Ikeda ◽  
...  
Keyword(s):  
Chromosome Number ◽  
Diploid Species ◽  
Size Variation ◽  
Chromosome Length ◽  
Basic Chromosome Number ◽  
Somatic Chromosome Number ◽  
Genome Size Variation ◽  
Basic Chromosome ◽  
Acrocentric Chromosomes ◽  
Intrachromosomal Asymmetry

Comparative karyomorphological analyses of six out of the eight white-flowered species of Eranthis sect. Shibateranthis have been carried out. All studied specimens of E. byunsanensis, E. lobulata, E. pinnatifida, and E. stellata had a somatic chromosome number 2n = 16 with basic chromosome number x = 8. On the contrary, E. tanhoensis and E. sibirica had a basic chromosome number x = 7. The specimens of E. tanhoensis were diploid with 2n = 14, while the specimens of E. sibirica were polyploid with 2n = 42. Monoploid chromosome sets of the investigated diploid species had 4–5 metacentric chromosomes and 2–4 submetacentric/subtelocentric/acrocentric chromosomes. The highest level of interchromosomal asymmetry, estimated via CVCL, was found in E. byunsanensis and E. pinnatifida. The highest levels of intrachromosomal asymmetry (MCA) and heterogeneity in centromere position (CVCI) were found in E. lobulata and E. byunsanensis, while E. sibirica had the most symmetric karyotype. A multivariate PCoA analysis of basic karyotype parameters (2n, x, THL, CVCL, MCA, and CVCI) highlighted no overlap among species accessions, which was also confirmed by LDA. The average absolute monoploid DNA content (1Cx) of the 23 investigated samples of six Eranthis species varied from 9.26 ± 0.25 pg in E. sibirica to 15.93 ± 0.32 pg in E. stellata. Overall karyological affinity was highlighted between E. lobulata and E. stellata, on one side, and between E. byunsanensis and E. pinnatifida, on the other side. Interestingly, there was no significant correlation between total haploid (monoploid) chromosome length (THL) and 1Cx values in these species.

scholarly journals In vitro propagation and cytological analysis of Sophora mollis Royle: an endangered medicinal shrub

2021 ◽  
Vol 19 (1) ◽  
Author(s):  
Aakriti Bhandari ◽  
Harminder Singh ◽  
Amber Srivastava ◽  
Puneet Kumar ◽  
G. S. Panwar ◽  
...  
Keyword(s):  
Chromosome Number ◽  
Average Length ◽  
Germplasm Conservation ◽  
Basic Chromosome Number ◽  
Shoot Tip ◽  
Ex Situ ◽  
Ms Medium ◽  
Basic Chromosome ◽  
Shoot Tip Explants

Abstract Background Sophora mollis Royle (family Fabaceae, subfamily-Papilionaceae) is a multipurpose legume distributed in plains and foothills of the North-West Himalaya to Nepal and is facing high risk of extinction due to habitat loss and exploitation by the local people for its fuel and fodder values. Therefore, the present study was conducted to standardize a micropropagation protocol for Sophora mollis by using shoot tip explants and to study the meiotic chromosome count in the species. Results Multiple shoots were induced in shoot tip explants of Sophora mollis in Murashige and Skoog medium supplemented with different concentrations of cytokinins alone (BAP, TDZ, and Kinetin) and in combination with varying concentrations of NAA. MS medium supplemented with BAP (8.9 μM) was observed to be the optimal medium for multiple shoot induction and maximum 25.32 shoots per explant was obtained with average length of 4.5 ± 0.8 cm. In vitro developed shoots were transferred onto rooting media supplemented with different concentrations of auxin (IAA, IBA, and NAA). Maximum 86% rooting was observed in half-strength MS medium supplemented with 21.20 μM NAA with an average of 21.26 roots per culture. In vitro raised plantlets were adapted to greenhouse for better acclimatization and 60% plants were successfully transferred to the open environment. Based on the chromosome counts available from the literature and the current study, the species tend to show a basic chromosome number of x = 9. Conclusion The micropropagation protocol standardized can be helpful for the ex situ mass multiplication and germplasm conservation of the endangered species. Moreover, the ex situ conservation approach will be helpful in actively bridging the gap between ex situ and in situ approaches through the reintroduction of species in the wild. The cytological studies revealed the basic chromosome number x = 9 of the species.

Chromosome morphology of Clematis, subsection Viornae (Ranunculaceae)

1976 ◽  
Vol 54 (10) ◽  
pp. 1135-1139 ◽  
Author(s):  
W. Michael Dennis
Keyword(s):  
Chromosome Number ◽  
Somatic Chromosome ◽  
Chromosome Complement ◽  
Chromosome Morphology ◽  
Terminal Region ◽  
Somatic Chromosome Number ◽  
Median Region ◽  
Acrocentric Chromosomes ◽  
Subterminal Region ◽  
Marked Stability

Cytological studies were made on the following taxa: C. addisonii, C. filifera, C. glaucophylla, C. pitcheri, C. reticulata, C. texensis, C. versicolor, and C. viorna. All species were found to have a somatic chromosome number of 16 with a uniform karyotype consisting of five pairs of metacentric chromosomes with centromeres in the median region and three pairs of acrocentric chromosomes, two pairs with centromeres in the terminal region and one pair with centromeres in the subterminal region. These findings agree with reports of chromosome number and karyotype for other species of Clematis and suggest a marked stability of chromosome complement in the genus.

Investigations of the inheritance of flower variegation in Mirabilis jalapa L. 3. Somatic chromosome number, 4. Distribution of the pigments and 5. Chromatographic studies

Euphytica ◽  
1975 ◽  
Vol 24 (1) ◽  
pp. 6-12 ◽  
Author(s):  
W. N. M. Van Kester ◽  
C. J. T. Spitters ◽  
L. Vosselman ◽  
J. M. M. Engels ◽  
A. C. Zeven
Keyword(s):  
Chromosome Number ◽  
Somatic Chromosome ◽  
Somatic Chromosome Number ◽  
Mirabilis Jalapa

scholarly journals Relations and evolution in Cheilanthes (Sinopteridaceae, Pteridophita) in Macaronesia and Mediterranean area, deduced from genome analysis of their hybrids

1983 ◽  
Vol 8 ◽  
pp. 101-126 ◽  
Author(s):  
G. Vida ◽  
A. Major ◽  
T. Reichstein
Keyword(s):  
Chromosome Number ◽  
Genome Analysis ◽  
Chromosome Doubling ◽  
Diploid Species ◽  
Mediterranean Area ◽  
Basic Chromosome Number ◽  
The Other ◽  
Experimental Conditions ◽  
Natural Group ◽  
Basic Chromosome

Nine species of "Cheilantoid ferns" are known to grow in Macaronesia and the Mediterranean basin. Two of them (lacking a pseudo-indusium and having the basic chromosome number X = 29), both aggregate species which we prefer to retain in Notholaena, are not included in this study. The other seven species (with distinct pseudo-indusium and the basic chromosome number X = 30), which we accept as members of the genus Cheilanthes Sw. sensu stricto, were subjected to detailed genome analysis of their natural and experimentally produced hybrids and shown to represent an aggregate of four very distinct ancestral diploids and three allotetraploids. The latter must have once been formed by chromosome doubling in the three diploid hybrids of C. maderensis Lowe with the other three diploid species. Theoretically three more allotetraploids would be possible but their formation has obviously been prevented by the geographical separation of the three respective diploids. The most widely distributed of the tetraploids, i.e. C. pteridioides (Reich.) C.Chr. has also been resynthesized from its ancestors (still sympatric) under experimental conditions. The intermediate morphology of the allotetraploids (as compared with their diploid ancestors) is obviously the reason why their status and existence has so long escaped recognition in Europe. These seven species form a natural group and, in our opinion, should not be divided into sections.

Meiotic chromosome behaviour in Cenchrus ciliaris

Bothalia ◽  
1998 ◽  
Vol 28 (1) ◽  
pp. 83-90 ◽  
Author(s):  
N. C. Visser ◽  
J. J. Spies
Keyword(s):  
Chromosome Number ◽  
Meiotic Chromosome ◽  
Basic Chromosome Number ◽  
Chromosome Behaviour ◽  
Meiotic Abnormalities ◽  
Single Specimen ◽  
Cenchrus Ciliaris ◽  
Basic Chromosome ◽  
Single Genome ◽  
Meiotic Irregularities

A basic chromosome number of x = 9 has been confirmed for Cenchrus ciliaris L. Polyploidy is common and levels vary from tetraploid to hexaploid. Aneuploidv is reported for a single specimen, where two chromosomes of a single genome were lost. Various meiotic irregularities were observed. The highest incidence of meiotic abnormalities was observed in the pentaploid specimens. This was attributed to their uneven polyploid level All specimens varied from segmental alloploid to alloploid.

Chromosome studies on African plants. 9. Chromosome numbers in Ehrharta (Poaceae: Ehrharteae)

Bothalia ◽  
1989 ◽  
Vol 19 (1) ◽  
pp. 125-132 ◽  
Author(s):  
J. J. Spies ◽  
E. J. L. Saayman ◽  
S. P. Voges ◽  
G. Davidse
Keyword(s):  
Chromosome Number ◽  
Ploidy Level ◽  
Chromosome Numbers ◽  
Basic Chromosome Number ◽  
B Chromosomes ◽  
Basic Chromosome ◽  
Cytogenetic Studies ◽  
African Plants ◽  
First Time

Cytogenetic studies of 53 specimens of 14 species of the genus  Ehrharta Thunb. confirmed a basic chromosome number of 12 for the genus. Chromosome numbers for 13 species are described for the first time. The highest ploidy level yet observed in the genus (2n = lOx = 120) is reported for E. villosa var.  villosa. B chromosomes were observed in several specimens of four different species.

Chromosome studies on African plants. 11. The tribe Andropogoneae (Poaceae: Panicoideae)

Bothalia ◽  
1994 ◽  
Vol 24 (2) ◽  
pp. 241-246 ◽  
Author(s):  
J. J. Spies ◽  
T. H. Troskie ◽  
E. Van der Vyver ◽  
S. M. C Van Wyk
Keyword(s):  
Chromosome Number ◽  
Basic Chromosome Number ◽  
Basic Chromosome ◽  
African Plants

Representative specimens of various species of the genera  Andropogon L.,  Cymbopogon Spreng.,  Elionurus Kunth ex Willd.,  Hyparrhenia Foum. and  Hyperthelia Clayton were cytogenetically studied. All specimens had a secondary basic chromosome number of ten. Polyploidy, either as alloploidy or segmental alloploidy. was frequent. The taxa studied represent mature polyploid complexes.  

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