scholarly journals SEXUAL PLANTS WITH HIGH CHROMOSOME NUMBER FROM AN INDIVIDUAL PLANT SELECTION IN A NATURAL POPULATION OF GUAYULE AND MARIOLA

Genetics ◽  
1946 ◽  
Vol 31 (2) ◽  
pp. 117-124
Author(s):  
Eldon J Gardner
Keyword(s):  
Chromosome Number ◽  
Natural Population ◽  
Individual Plant ◽  
Plant Selection ◽  
High Chromosome Number

scholarly journals High Chromosome Number and Giant Postreductional Sex Chromosomes in the Beetle Walterianella venusta Schaufuss (Chrysomelidae, Alticinae)

1969 ◽  
Vol 47 (3) ◽  
pp. 154-163
Author(s):  
Niilo Virkki
Keyword(s):  
Chromosome Number ◽  
Sex Chromosomes ◽  
High Chromosome Number

A high chromosome number for a coleopteran, 22-J-X+y, was encountered in an alticine, Walterianella venusta Schaufuss. The autosomes are very short, metacentric; the sex chromosomes very long and also metacentric. The sex chromosomes are desynaptic and postreductional in spermatogenesis. It is assumed that two trends operate in the evolution of the alticine chromosomes, first, the autosomal chromatin being incorporated repeatedly in the sex chromosomes, and second, the occurrence of the multiplication of the short autosomes.

Cytology of the fern flora of Tristan da Cunha

1968 ◽  
Vol 170 (1021) ◽  
pp. 361-379 ◽  
Keyword(s):  
Chromosome Number ◽  
Southern Hemisphere ◽  
Endemic Species ◽  
Special Interest ◽  
New Record ◽  
Atlantic Basin ◽  
High Chromosome Number ◽  
Tristan Da Cunha

Twenty species out of a total of twenty-six leptosporangiate ferns known to occur on Tristan da Cunha have been examined cytologically. Four species have been independently examined from Gough with concordant results. Hymenophyllum tunbrigense , included among the Tristan species, is a new record for the island. Other points of special interest about individual taxa include demonstration of an extremely high chromosome number ( n = 174) in the supposedly endemic species Eriosorus cheilanthoides , demonstration of the existence of two different cytotypes (one only present on Tristan) within Blechnum penna-marina in the southern hemisphere and of complex polyploid relationships affecting several other taxa which are discussed individually. In addition the cytological composition of the fern flora as a whole is discussed in relation to other temperate and tropical floras in or near the Atlantic basin.

scholarly journals Genome size stability despite high chromosome number variation in Carex gr. laevigata

2015 ◽  
Vol 102 (2) ◽  
pp. 233-238 ◽  
Author(s):  
Marcial Escudero ◽  
Enrique Maguilla ◽  
João Loureiro ◽  
Mariana Castro ◽  
Sílvia Castro ◽  
...  
Keyword(s):  
Chromosome Number ◽  
Genome Size ◽  
High Chromosome Number ◽  
Size Stability ◽  
Number Variation ◽  
Chromosome Number Variation

CYTOGEOGRAPHY AND EVOLUTION OF THE DESGHAMPSIA CAESPITOSA COMPLEX

1963 ◽  
Vol 41 (5) ◽  
pp. 719-742 ◽  
Author(s):  
Shoichi Kawano
Keyword(s):  
Chromosome Number ◽  
Geographical Distribution ◽  
Morphological Variation ◽  
Phylogenetic Relationships ◽  
Basic Number ◽  
Basic Chromosome Number ◽  
Basic Form ◽  
Basic Chromosome ◽  
High Chromosome Number ◽  
Deschampsia Caespitosa

The chromosome number, karyotype, and morphological variation of plants of the Deschampsia caespitosa complex are reported in this paper. It is shown that the chromosome number of 2n = 26 is most common in typical D. caespitosa (L.) Beauv. But, remembering the basic chromosome number in the Agrostideae, the original basic number of the genus Deschampsia is considered to be x = 7. Thus, a reduction of the chromosome number from 28 to 26 is speculated in this particular group of Deschampsia. The plant from Mt. Albert, Canada, referable to D. caespitosa ssp. littoralis (Reut.) Rchb., has a high chromosome number of 2n = 49. Considering the morphological affinity between D. caespitosa ssp. littoralis and D. alpina Roem. & Schult., as well as their geographical distribution, parallel development of the plants with such high irregular chromosome number is assumed.The karyotype of D. caespitosa s. str. was also investigated. This species has a highly specialized asymmetrical karyotype, viz., K(2n) = 26 = 4 V + 10 J + 12 I.On the basis of cytology, morphology, ecology, and geographical distribution, the phylogenetic relationships within this complex were considered. The littoralis type, having well-developed panicles, large spikelets, three (rarely four) florets, and a preference for wet terrestrial sites, is speculated to be the most basic form in the D. caespitosa complex, even though the type with smaller spikelets, i.e., caespitosa s. str. is at the present time much more abundant. Various other population groups such as D. caespitosa v. parviflora (Thuill.) Coss. & Germ., D. brevifolia R. Br., D. alpina Roem. & Schult., and the species of the bottnica group (including D. beringensis Hultén, D. bottnica (Wahlenb.) Trin., D. congestiformis Booth, D. holciformis F. & C. Presl, D. mackenzieana Raup, D. macrothyrsa Tatewaki et Ohwi, D. obensis Roshev., and D. wibeliana Schur.) are presumed to be more specialized.

STOLAINE CASSIDINES (COLEOPTERA, CHRYSOMELIDAE) WITH Xyp SEX CHROMOSOMES AND A DERIVATIVE SYSTEM XpneoXneoYp

1974 ◽  
Vol 16 (2) ◽  
pp. 433-440 ◽  
Author(s):  
E. S. de Vaio ◽  
A. Postiglioni
Keyword(s):  
Chromosome Number ◽  
Sex Chromosomes ◽  
High Chromosome Number ◽  
Multiple Sex Chromosomes ◽  
Autosome Translocation ◽  
Derivative System ◽  
Very High

Three species of Cassidines were cytologically studied. Chelymorpha indigesta and C. variabilis, with 10II + Xyp, have a relatively primitive Coleopteran karyotype and the sex chromosomes form a parachute-like bivalent. Botanochara angulata, belonging to the same tribe, Stolaini, presents an exceptional karyotype with a very high chromosome number (2n = 51 ♀) and multiple sex chromosomes XpneoXneoYp. This system has derived from the Xyp by a yp-to-autosome translocation.

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