Chromosome numbers in the Boronieae (Rutaceae) and their bearing on the evolutionary development of the tribe in the Australian flora

1954 ◽  
Vol 2 (3) ◽  
pp. 287 ◽  
Author(s):  
S Smith-White
Keyword(s):  
Chromosome Numbers ◽  
Chromosomal Instability ◽  
Chromosomal Evolution ◽  
Basic Number ◽  
Evolutionary Development ◽  
Base Number ◽  
Polyploid Species ◽  
Cytological Data ◽  
Australian Flora ◽  
Two Stages

Chromosome numbers are reported for 69 species, belonging to 11 genera of the Boronieae. In comparison with the other divisions of the Rutaceae, chromosome numbers are remarkably variable, and base numbers range from 7 to 19. Seven genera and 10 species belonging to other tribes and subfamilies of the Rutaceae are also reported. In common with the Aurantoideae, Xanthoxyleae, and Ruteae, the primitive number in the Boronieae is almost certainly 9. Chromosomal evolution has involved both aneuploidy and polyploidy. In both diploid and polyploid species, chromosome pairing is essentially regular. All the polyploids, even within recognized taxonomic species, are essentially of allopolyploid constitution. Two stages in the occurrence of polyploidy can be recognized — the first giving rise to groups of generic status, and the second to polyploid species within genera. Many genera possess chromosome numbers which could be derived by aneuploid reduction, followed by polyploidy. Some fundamental change in chromosonle structure in the primitive Boronieae stock is suggested as a cause of its early chromosomal instability. From a correlation of geographical and cytological data and inference, a hypothesis of the historical development of the Boronieae in Australia is presented. Following their isolation in the continent, and the occurrence of a fundamental reorganization in chromosome structure, a period of generic radiation, with changes in basic number, occurred before the Miocene. Particular chromosome numbers are characteristic of genera. Differences in base number rank as generic rather than as specific criteria. On this basis the accepted taxonomy is essentially sound, and only minor alterations are suggested. Crowea is established, and Eriostemon lanceolatzis is separated from its congeners. Some sections of Boronia are deserving of generic rank, and B. serrulata is wrongly placed in the section Terminales.

NEW CHROMOSOME COUNTS IN OLD WORLD GESNERIACEAE: NUMBERS FOR SPECIES HITHERTO REGARDED ASCHIRITA, AND THEIR SYSTEMATIC AND EVOLUTIONARY SIGNIFICANCE

2012 ◽  
Vol 69 (2) ◽  
pp. 323-345 ◽  
Author(s):  
F. Christie ◽  
S. Barber ◽  
M. Möller
Keyword(s):  
Chromosome Numbers ◽  
Taxonomic Revision ◽  
Basic Number ◽  
Evolutionary Significance ◽  
Chromosome Counts ◽  
Old World ◽  
Phylogenetic Studies ◽  
Cytological Data ◽  
Phylogenetic Data ◽  
Primulina Tabacum

Chromosome numbers were determined in 23 accessions representing 21 species hitherto belonging toChirita(Gesneriaceae), a genus that has recently been remodelled and split into five different genera:Damrongia,Henckelia,Liebigia,MicrochiritaandPrimulina. The previously monotypicPrimulina tabacumwas also investigated. Counts for 19 species were new, two were confirmatory and two gave different numbers from previously published counts. The results here, together with previously published cytological data for the erstwhile genusChirita, were analysed in the light of the taxonomic revision of the genus and published phylogenetic data.Chiritawas originally highly heterogeneous in chromosome numbers, including seven different somatic numbers, 2n= 8, 18, 20, 28, 32, 34 and 36. Among the five remodelled genera,Henckeliawas found to be as equally heterogeneous as the erstwhileChirita,Microchiritaincluded only two chromosome numbers, 2n= 18 and 34, the three species ofDamrongiawere uniform with 2n= 18, while species belonging to the extendedPrimulinashowed only one basic number,x= 18, with 15 samples being diploid, and one being tetraploid. In the light of recent phylogenetic studies, polyploid as well as dysploid changes appear to have shaped the genomes of the newly defined generaHenckelia,Microchiritaand, to a lesser degree,Primulina.

The cytology of Brachycome. I. The subgenus Eubrachycome: A general survey

1970 ◽  
Vol 18 (1) ◽  
pp. 99 ◽  
Author(s):  
S Smith-White ◽  
CR Carter ◽  
HM Stace
Keyword(s):  
Chromosome Number ◽  
Chromosome Numbers ◽  
Base Number ◽  
Undescribed Species ◽  
General Survey ◽  
Chromosome Races ◽  
Chromosomal Change ◽  
Cytological Data ◽  
Wide Range ◽  
Annual Habit

Chromosome number determinations and cytological observations are reported for 37 recognized taxonomic species and varieties, and for a number of undescribed species and chromosome races in Eubrachycome. Additionally, chromosome numbers are reported for six species of Metabrachycome and two species of related genera. A wide range of numbers has been found. It is inferred that x = 9 is the primitive base number in the group. Eubrachycome has used various modes of chromosomal change, including polyploidy, amphidiploidy, decrease in base number, and the establishment of B. chromosomes. The present taxonomy of the group requires revision, taking into account cytological data. Primitive Eubrachycome was probably a mesic perennial. The evolution of desert species has involved reduction in chromosome number and the adoption of the annual habit, but other methods of desert adaptation have been available. Many species are chromosomally unstable, and may have been subject to catastrophic selection.

Neptunia windleriana: A New Polyploid Species of Neptunia (Leguminosae) from Brazil Recognized by Anatomy, Morphology and Cytogenetics

2020 ◽  
Vol 45 (3) ◽  
pp. 483-494
Author(s):  
Juliana Santos Silva ◽  
Márcia Santos Carvalho ◽  
Géssica Souza Santos ◽  
Francyane Tavares Braga ◽  
Maria José Gomes de Andrade ◽  
...  
Keyword(s):  
Vascular System ◽  
Basic Number ◽  
Bundle Sheath ◽  
Distribution Data ◽  
Base Number ◽  
Vascular Bundles ◽  
Polyploid Species ◽  
Widespread Species ◽  
Bundle Sheath Cells ◽  
First Time

Abstract—Neptunia windleriana, a new polyploid species of the pantropical genus Neptunia, is described and illustrated. This plant is endemic to the state of Bahia, Brazil, and is found in areas of Caatinga near the São Francisco River. Among the species occurring in Brazil, it is most similar to N. plena, a widespread species, by having a gland on the petiole, but it differs mainly by the number of pairs of pinnae and leaflets, shape of the spike in bud, and the size of the peduncles. It is morphologically distinct from all other species of the genus by the combination of prostrate subshrub habit, smaller leaves, shorter petiole and shorter rachis length, few-flowered, globose spikes, 10 stamens, and glabrous ovary. The presence of monocrystals in the bundle sheath cells of the bracts of N. windleriana is recorded here for the first time for the genus, together with the chromosome number (2n = 56 vs. 2n = 28, ∼52, 54, 56, 72, 78 for three other species of the genus occurring in Brazil), it can be also used to identify the species. The epidermis of the stipules, leaflet, and bracts of N. windleriana is uniseriate, with paracytic stomata. The vascular system has collateral arrangement with the vascular bundles covered by a sheath, with or without isolated monocrystals. Our data support earlier hypotheses that Neptunia has a base number of x2 = 14 which seems to be a secondary basic number that originated from an ancestral stock with x1 = 7 and underwent karyotypic evolution by polyploidy. A key to the Brazilian species of Neptunia as well as anatomical, cytogenetic, taxonomic, and geographic distribution data, ilustrations and photos are provided.

A natural intergeneric hybrid of Gesneriaceae from Brazil

Phytotaxa ◽  
2021 ◽  
Vol 497 (2) ◽  
pp. 79-96
Author(s):  
ANDRÉA ONOFRE DE ARAUJO ◽  
MAURO PEIXOTO ◽  
CINTIA NEVES DE SOUZA ◽  
EDUARDO CUSTÓDIO GASPARINO ◽  
JULIANA TOLEDO FARIA ◽  
...  
Keyword(s):  
Chromosome Numbers ◽  
Pollen Morphology ◽  
Pollen Grains ◽  
Intergeneric Hybrid ◽  
Morphological Characters ◽  
Natural Hybrid ◽  
Pollen Data ◽  
Cytological Data ◽  
High Viability ◽  
Structural Abnormalities

A natural hybrid between Goyazia and Mandirola (Gloxiniinae, Gesneriaceae) from Cerrado (Brazil) is here described, supported by pollen morphology, cytological data and morphological characters. The microsporogenesis of Mandirola hirsuta and that of the hybrid were analyzed in order to evaluate the cytogenetic characteristics. The haploid chromosome numbers observed were n = 12 for M. hirsuta and n = 11, 13, 16 and 26 for the hybrid. Structural abnormalities (monads, dyads, triads and micronuclei) were observed at the final of the hybrid’s meiosis. High viability rates of the pollen were recorded for Goyazia and Mandirola (>90%) and low viability for the hybrid (34.7%). The pollen grains were acetolyzed, measured and photographed for pollen morphology analysis. Quantitative pollen data were analyzed through descriptive and multivariate statistics. The hybrid has intermediate pollen characteristics between G. petraea and M. hirsuta; it is more related to G. petraea by the measures of diameters and ectoapertures; it is more similar to M. hirsuta mainly regarding the microreticulum on the mesocolpium region. The hybrid and Mandirola share vegetative and flower size, while the colors of the hybrid are similar to Goyazia. Pollen morphology, cytological data and morphological characters brought clear evidence for the recognition of the intergeneric hybrid, which we named as Goydirola x punctata.

CYTOTAXONOMY, PHYLOGENY, AND CANADIAN DISTRIBUTION OF CIRSIUM UNDULATUM AND CIRSIUM FLODMANII

1961 ◽  
Vol 39 (1) ◽  
pp. 21-33 ◽  
Author(s):  
C. Frankton ◽  
R. J. Moore
Keyword(s):  
North American ◽  
Chromosome Numbers ◽  
World Wide ◽  
North American Species ◽  
Base Number ◽  
Total Length ◽  
The World ◽  
Cirsium Undulatum

The morphology and specific differences of Cirsium undulatum (Nutt.) Spreng. and of C. flodmanii (Rydb.) Arthur are described and their Canadian distributions are reported in detail. The chromosome numbers are C. undulatum f. undulatum and f. album Farwell, 2n = 26; C. flodmanii f. flodmanii and f. albiflorum D. Löve, 2n = 22. The origin of four North American species of Cirsium that do not follow the world-wide base number 17 is discussed; it is postulated that reduction in number has occurred by translocations. The chromosomes of species with reduced numbers are larger than those of the unreduced species but the total length of the chromosomes of both groups is approximately the same.

scholarly journals Descending Dysploidy and Bidirectional Changes in Genome Size Accompanied Crepis (Asteraceae) Evolution

Genes ◽  
2021 ◽  
Vol 12 (9) ◽  
pp. 1436
Author(s):  
Magdalena Senderowicz ◽  
Teresa Nowak ◽  
Magdalena Rojek-Jelonek ◽  
Maciej Bisaga ◽  
Laszlo Papp ◽  
...  
Keyword(s):  
Genome Size ◽  
Dna Sequences ◽  
Chromosome Numbers ◽  
Karyotype Evolution ◽  
Base Number ◽  
Ancestral State ◽  
Ancestral Genome ◽  
Independent Events ◽  
Karyotype Asymmetry ◽  
Major Direction

The evolution of the karyotype and genome size was examined in species of Crepis sensu lato. The phylogenetic relationships, inferred from the plastid and nrITS DNA sequences, were used as a framework to infer the patterns of karyotype evolution. Five different base chromosome numbers (x = 3, 4, 5, 6, and 11) were observed. A phylogenetic analysis of the evolution of the chromosome numbers allowed the inference of x = 6 as the ancestral state and the descending dysploidy as the major direction of the chromosome base number evolution. The derived base chromosome numbers (x = 5, 4, and 3) were found to have originated independently and recurrently in the different lineages of the genus. A few independent events of increases in karyotype asymmetry were inferred to have accompanied the karyotype evolution in Crepis. The genome sizes of 33 Crepis species differed seven-fold and the ancestral genome size was reconstructed to be 1 C = 3.44 pg. Both decreases and increases in the genome size were inferred to have occurred within and between the lineages. The data suggest that, in addition to dysploidy, the amplification/elimination of various repetitive DNAs was likely involved in the genome and taxa differentiation in the genus.

scholarly journals Polyploidy and Speciation in Pteris (Pteridaceae)

2012 ◽  
Vol 2012 ◽  
pp. 1-7 ◽  
Author(s):  
Yi-Shan Chao ◽  
Ho-Yih Liu ◽  
Yu-Chung Chiang ◽  
Wen-Liang Chiou
Keyword(s):  
Reproductive Biology ◽  
Evolutionary History ◽  
Base Number ◽  
Ploidy Levels ◽  
Cytological Data ◽  
The Relationship ◽  
Complex Evolutionary History

The highest frequency of polyploidy among plants is considered to occur in the Pteridophytes. In this study, we focused on polyploidy displayed by a specific fern taxon, the genus Pteris L. (Pteridaceae), comprising over 250 species. Cytological data from 106 Pteris species were reviewed. The base number of chromosomes in Pteris is 29. Polyploids are frequently found in Pteris, including triploids, tetraploids, pentaploids, hexaploids, and octoploids. In addition, an aneuploid species, P. deltodon Bak., has been recorded. Furthermore, the relationship between polyploidy and reproductive biology is reviewed. Among these 106 Pteris species, 60% exhibit polyploidy: 22% show intraspecific polyploidy and 38% result from polyploid speciation. Apogamous species are common in Pteris. Diploids are the most frequent among Pteris species, and they can be sexual or apogamous. Triploids are apogamous; tetraploids are sexual or apogamous. Most Pteris species have one to two ploidy levels. The diverse ploidy levels suggest that these species have a complex evolutionary history and their taxonomic problems require further clarification.

Karyotypes of Leptarrhena and Tanakaea (Saxifragaceae)

1984 ◽  
Vol 62 (4) ◽  
pp. 671-673 ◽  
Author(s):  
Douglas E. Soltis
Keyword(s):  
Chromosome Number ◽  
Chromosome Numbers ◽  
Chromosomal Evolution ◽  
Conservative Nature ◽  
Chromosomal Data ◽  
Base Chromosome Number ◽  
Flavonoid Chemistry

In an attempt to clarify subtribal relationships in tribe Saxifrageae, chromosome numbers and karyotypes were determined for the two species comprising subtribe Leptarrheninae: Leptarrhena pyrolifolia and Tanakaea radicans. In both species 2n = 14, a common chromosome number throughout Saxifrageae. The two species have distinctive karyotypes that appear to differ in the centromeric positions of three pairs of chromosomes. These findings, in conjunction with earlier studies, demonstrate that genera of Saxifrageae often differ karyotypically. Leptarrhena exhibits considerable karyotypic similarity to genera of subtribe Saxifraginae characterized by a base chromosome number of x = 7. Chromosomal data, therefore, do not clearly differentiate subtribes Saxifraginae and Leptarrheninae. This observation is in agreement with evidence from paly-nology and flavonoid chemistry. Karyotypic studies continue to demonstrate the conservative nature of chromosomal evolution in tribe Saxifrageae.

New chromosome numbers for rutaceae

1992 ◽  
Vol 5 (4) ◽  
pp. 501 ◽  
Author(s):  
HM Stace ◽  
JA Armstrong
Keyword(s):  
Chromosome Numbers ◽  
Pollen Sterility ◽  
Chromosome Counts ◽  
Cytological Data ◽  
Taxonomic Implications

Chromosome counts for 30 taxa, representing five genera, are reported for Rutaceae subfamily Rutoideae, mostly in the Australasian tribe Boronieae. We found n = 10 for Boronia algida which is previously unreported in the genus, and a sterile triploid taxon in Zieria. Generic chromosome numbers of n = 18 in Zieria, n = 16 in Phebalium and n = 14 in Eriostemon sens. lat. occur, while Boronia shows cytoevolution on n = 18, 11, 10, 9. Pollen sterility and possible apomixis is indicated in some species. Some taxonomic implications of cytological data in the tribe Boronieae are discussed.

Molecular systematics of Australian Podolepis (Asteraceae: Gnaphalieae): evidence from DNA sequences of the nuclear ITS region and the chloroplast matK gene

2000 ◽  
Vol 13 (5) ◽  
pp. 709 ◽  
Author(s):  
N. Konishi ◽  
K. Watanabe ◽  
K. Kosuge
Keyword(s):  
Dna Sequences ◽  
Its Region ◽  
Chromosomal Evolution ◽  
Internal Transcribed Spacers ◽  
Nuclear Ribosomal Dna ◽  
Base Number ◽  
Monophyletic Clade ◽  
Matk Gene ◽  
Nuclear Its ◽  
Generic Relationships

The generic circumscription and intra-generic relationships of the genus Podolepis Labill., with various chromosome numbers from n = 12 to n = 3, were examined by sequences of the internal transcribed spacers (ITS) of nuclear ribosomal DNA and the matK gene of chloroplast DNA. The topology of the ITS tree for 17 species and the matK tree for 18 species of the genus Podolepis sensu Davis (1957) and Anderberg (1991) and 15 taxa from eight related genera (Anderberg 1989, 1991, 1994) are basically concordant. Except for P. georgei Diels andP. kendallii F.Muell., parsimony analyses support the monophyly of the genus Podolepis sensu Davis (1957) and Anderberg (1991). The genera of Asteridea Lindl. and Pterochaeta Steetz are sisters toPodolepis in the combined tree based on the ITS and matK sequences. Within the monophyletic clade of the genus Podolepis, three lineages are identified. The chromosome base number of x = 12 may be ancestral in the genus Podolepis. The dysploidal reduction in chromosome number from n = 12 to n = 10 and 9, from n = 12 to n = 8 and 7, and from n = 12 to n = 11 and 3 in three lineages, respectively, is the primary mode of chromosomal evolution in this genus. Total karyotypic length (= genome size) is much greater in perennials than in annuals within the genus Podolepis. The number of pappus bristles on outer female florets tends to decrease and they are absent in some annuals of this genus, while myxogenic cells on the pericarp become prominent.

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