The influence of cell size and chromosome dosage on cold-hardiness expression in the Triticeae

A. E. Limin; D. B. Fowler

doi:10.1139/g89-496

The influence of cell size and chromosome dosage on cold-hardiness expression in the Triticeae

Genome ◽

10.1139/g89-496 ◽

1989 ◽

Vol 32 (4) ◽

pp. 667-671 ◽

Cited By ~ 17

Author(s):

A. E. Limin ◽

D. B. Fowler

Keyword(s):

Chromosome Number ◽

Cell Size ◽

Common Wheat ◽

Ploidy Level ◽

Guard Cell ◽

Cold Hardiness ◽

Gene Dosage ◽

Large Cell ◽

Gene Dosage Effect ◽

Ploidy Levels

The influence of cell size and chromosome dosage on cold-hardiness expression was investigated in members of the tribe Triticeae. Mean leaf guard-cell lengths for ploidy levels of 2x, 4x, 6x, and 8x were found to increase by approximately 10 μm with each addition of two basic (x = 7) genomes, indicating that larger cell size was associated with higher ploidy level. Poor expression of cold hardiness in amphiploids was associated with large cell size. However, comparisons among and within species indicated that ploidy level was not the only factor determining cell size. Significant differences in guard-cell length were observed among common wheat (Triticum aestivum L. em. Thell.) cultivars. Cell size differences among cultivars were found in both hardened and nonhardened common wheat plants and these differences were associated with cultivar cold hardiness (r = 0.95, P ≤ 0.01). The evidence indicated that smaller cell size influenced cold tolerance by amplifying the expression of cold-hardiness genes in cold-acclimated plants, probably by reducing the degree of cell contraction from freeze dehydration. A chromosome (gene) dosage effect that favored the expression of genes from the parent species contributing the higher chromosome number was also shown to play an important role in the expression of cold hardiness in interspecific hybrids and amphiploids. Comparison of related species with similar cell size and chromosome number suggested differences in the effectiveness of cold hardiness conferring genes. Observations made on species from the Triticeae indicate that when cold-hardiness potential is limited at the diploid level, a plant group may expand its cold-hardiness range by "loading up" on existing cold-hardiness genes by means of polyploidy. An increased genetic potential may then be further enhanced by selection for smaller cell size within the polyploid nucleotype. This process appears to have been responsible for the superior cold hardiness of hexaploids within the Triticum genus.Key words: cell size, cold hardiness, gene dosage, Triticeae, evolution, interspecific hybrid, Agropyron.

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Chromosome Number, Ploidy Level, and Nuclear DNA Content in 23 Species of Echeveria (Crassulaceae)

Genes ◽

10.3390/genes12121950 ◽

2021 ◽

Vol 12 (12) ◽

pp. 1950

Author(s):

Guadalupe Palomino ◽

Javier Martínez-Ramón ◽

Verónica Cepeda-Cornejo ◽

Miriam Ladd-Otero ◽

Patricia Romero ◽

...

Keyword(s):

Flow Cytometry ◽

Chromosome Number ◽

Ploidy Level ◽

Dna Content ◽

Chromosome Numbers ◽

Nuclear Dna ◽

Nuclear Dna Content ◽

Root Tips ◽

Ploidy Levels ◽

Dna Amounts

Echeveria is a polyploid genus with a wide diversity of species and morphologies. The number of species registered for Echeveria is approximately 170; many of them are native to Mexico. This genus is of special interest in cytogenetic research because it has a variety of chromosome numbers and ploidy levels. Additionally, there are no studies concerning nuclear DNA content and the extent of endopolyploidy. This work aims to investigate the cytogenetic characteristics of 23 species of Echeveria collected in 9 states of Mexico, analyzing 2n chromosome numbers, ploidy level, nuclear DNA content, and endopolyploidy levels. Chromosome numbers were obtained from root tips. DNA content was obtained from the leaf parenchyma, which was processed according to the two-step protocol with Otto solutions and propidium iodide as fluorochrome, and then analyzed by flow cytometry. From the 23 species of Echeveria analyzed, 16 species lacked previous reports of 2n chromosome numbers. The 2n chromosome numbers found and analyzed in this research for Echeveria species ranged from 24 to 270. The range of 2C nuclear DNA amounts ranged from 1.26 pg in E. catorce to 7.70 pg in E. roseiflora, while the 1C values were 616 Mbp and 753 Mbp, respectively, for the same species. However, differences in the level of endopolyploidy nuclei were found, corresponding to 4 endocycles (8C, 16C, 32C and 64C) in E. olivacea, E. catorce, E. juarezensis and E. perezcalixii. In contrast, E. longiflora presented 3 endocycles (8C, 16C and 32C) and E. roseiflora presented 2 endocycles (8C and 16C). It has been suggested that polyploidization and diploidization processes, together with the presence of endopolyploidy, allowed Echeveria species to adapt and colonize new adverse environments.

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Genome Size, Chromosome Number and Morphological Data Reveal Unexpected Infraspecific Variability in Festuca (Poaceae)

Genes ◽

10.3390/genes12060906 ◽

2021 ◽

Vol 12 (6) ◽

pp. 906

Author(s):

Gloria Martínez-Sagarra ◽

Sílvia Castro ◽

Lucie Mota ◽

João Loureiro ◽

Juan A. Devesa

Keyword(s):

Chromosome Number ◽

Genome Size ◽

Ploidy Level ◽

Morphological Data ◽

Chromosome Counting ◽

Ploidy Levels ◽

2C Dna Content ◽

Number Counts ◽

First Time ◽

Evolutionary Role

Polyploidy has played an important evolutionary role in the genus Festuca (Poaceae), and several ploidy levels (ranging from 2n = 2x = 14 to 2n = 12x = 84) have been detected to date. This study aimed to estimate the genome size and ploidy level of two subspecies belonging to the F. yvesii polyploid complex by flow cytometry and chromosome counting. The phenotypic variation of the cytotypes was also explored, based on herbarium material. The genome size of F. yvesii subsp. lagascae has been estimated for the first time. Nuclear 2C DNA content of F. yvesii subsp. summilusitana ranged from 21.44 to 31.91 pg, while that of F. yvesii subsp. lagascae was from 13.60 to 22.31 pg. We report the highest ploidy level detected for Festuca (2n = 14x = 98) and previously unknown cytotypes. A positive correlation between holoploid genome size and chromosome number counts shown herein was confirmed. The morphometric approach showed a slight trend towards an increase in the size of some organs consistent with the variation in the ploidy level. Differences in characters were usually significant only among the most extreme cytotypes of each subspecies, but, even in this case, the high overlapping ranges prevent their distinction.

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Leaf micromorphology of 19 Mentha taxa

Australian Journal of Botany ◽

10.1071/bt19054 ◽

2019 ◽

Vol 67 (7) ◽

pp. 463

Author(s):

Doaa M. Hanafy ◽

Paul D. Prenzler ◽

Rodney A. Hill ◽

Geoffrey E. Burrows

Keyword(s):

Chromosome Number ◽

Cell Size ◽

Dna Content ◽

Guard Cell ◽

Stomatal Density ◽

Glandular Trichomes ◽

Cell Length ◽

Leaf Micromorphology ◽

Leaf Surfaces ◽

Electron Microscopes

Mentha (mint) is a genus in the Lamiaceae with a worldwide distribution. It has a complex classification due to frequent hybridisation at the interspecific level, variation in basic chromosome number and the occurrence of polyploidy (diploid to nonaploid). Although there have been many studies of Mentha leaf micromorphology, usually only a few taxa were described. The aim of this study was to characterise the micromorphology of Mentha leaves. Nineteen Mentha taxa, covering all four sections of the genus, were grown under controlled conditions and adaxial and abaxial leaf surfaces were examined using stereo and scanning electron microscopes. This study included examination of the previously uninvestigated Australian species, M. australis and M. diemenica. The study revealed that average lamina length varied from 3 mm (M. requienii) to 34 mm (M. × niliaca) and leaves were sessile (M. spicata) to where petiole length was 50% of total leaf length (M. requienii). Peltate and capitate glandular trichomes were found on the adaxial and abaxial leaf surfaces of almost all taxa. Most taxa were hypostomatous. A few taxa had amphistomatous leaves which was interesting given that Mentha is a mesophytic genus naturally found in moist environments beside streambanks and lake shores. Average guard cell length varied from 14 µm (M. suaveolens) to 27 µm (M. × piperita f. citrata ‘Basil’) with larger guard cell length correlated with larger DNA content and chromosome number. Two species in section Pulegium (M. requienii and M. pulegium) had small laminas, relatively long petioles and high adaxial stomatal density which distinguished them from taxa in the other three sections. Larger DNA content in plants can be associated with larger cell size. Most studies of Mentha leaf micromorphology make no mention of ploidy. The present study indicates this should be considered when comparing relative cell size between species.

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A contribution to the taxonomy of the Oxytropis campestris complex in northwestern North America

Canadian Journal of Botany ◽

10.1139/b80-211 ◽

1980 ◽

Vol 58 (16) ◽

pp. 1820-1831 ◽

Cited By ~ 3

Author(s):

Wayne J. Elisens ◽

John G. Packer

Keyword(s):

North America ◽

Chromosome Number ◽

Cell Size ◽

Guard Cell ◽

Chromosome Numbers ◽

Species Status ◽

Polyploid Series ◽

Continental Divide ◽

Northwestern North America

The Oxytropis campestris complex in northwestern North America is a polyploid series comprising at least seven morphologically and geographically distinct taxa. In light of the data of the present study, the authors propose that five taxa be reelevated to species status: O. cusickii Greenm., O. monticola Gray, O. columbiana St. John. O. jordalii Porsild, O. varions (Rydb.) K. Schum.; and that two taxa be recombined as subspecies: O. monticola Gray ssp. dispar (A. Nels.) Elisens & Packer and O. jordalii Porsild ssp. davisii (Welsh) Elisens & Packer.Three different chromosome numbers are present in the complex and represent the tetraploid (2n = 32), hexaploid (2n = 48), and dodecaploid (2n = 96) condition. Three species have uniform chromosome numbers (O. cusickii, 2n = 48; O. jordalii, 2n = 32; and O. columbiana, 2n = 48), two taxa, O. varians and O. monticola ssp. monticola, exhibit two different chromosome numbers. No attempt to subdivide O. varians was undertaken as; with the exception of guard cell size, no differences were observed between hexaploid and dodecaploid representatives. At least two distinct entities appear to be present in O. monticola ssp. monticola, for, while morphologically, cytologically (2n = 32), and ecologically uniform east of the continental divide, it is quite variable in appearance and has a different chromosome number (2n = 48) west of the divide.

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Relationship between guard cell length and cold hardiness in wheat

Canadian Journal of Plant Science ◽

10.4141/cjps94-011 ◽

1994 ◽

Vol 74 (1) ◽

pp. 59-62 ◽

Cited By ~ 8

Author(s):

A. E. Limin ◽

D. B. Fowler

Keyword(s):

Water Content ◽

Cold Tolerance ◽

Cell Size ◽

Guard Cell ◽

Cold Hardiness ◽

Cell Length ◽

Crystal Formation ◽

Tissue Water Content ◽

Tissue Water ◽

Wide Range

Identification of plant characters associated with cold tolerance is useful for the development of plant-breeding selection procedures and understanding the underlying mechanisms of cold hardiness. This research investigates the association of guard cell length with cold tolerance and examines the relationship between cell size, as estimated from guard cell length, and other characters previously found to be highly correlated with cold tolerance in wheat (Triticum aestivum L. em. Thell.). Guard cell length was compared with field survival, LT50, tissue water content, and plant erectness of cultivars representing a wide range of cold tolerance levels. The three most cold-tolerant cultivars had the smallest cells, while the cultivar with the largest cell size was a spring type. There were significant (P ≤ 0.05) correlations between guard cell length and all cold-tolerance-related characters considered. Differences in guard cell length were most closely related to field survival as measured by Field Survival Index (FSI). Stepwise regression analysis indicated that cell size explained 45% of the variability in FSI. Cell size combined with plant erectness and tissue water content explained 88% of the variability in FSI. LT50 and cell size together explained 96% of the variability in FSI. The effects of cell size on cold hardiness may relate to its influence on cell water content and cellular mechanical stress during intercellular ice-crystal formation and freezing-induced dehydration. Guard cell size should be a useful selection tool in cultivar development programs that have increased cold hardiness as the breeding objective. Key words:Triticum aestivum, winter wheat, cold hardiness, guard-cell length, cell size

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Evidence of a gene-dosage effect for the glucocorticoid receptor in trisomy 18 mice

Acta Endocrinologica ◽

10.1530/acta.0.114s095 ◽

1987 ◽

Vol 116 (3_Suppl) ◽

pp. S95-S96

Author(s):

D. VOGLIOLO ◽

H. WINKING ◽

R. KNUPPEN

Keyword(s):

Glucocorticoid Receptor ◽

Gene Dosage ◽

Dosage Effect ◽

Trisomy 18 ◽

Gene Dosage Effect

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Apparent Lack of Gene Dosage Effect in the PLT Assay

Scandinavian Journal of Immunology ◽

10.1111/j.1365-3083.1977.tb02116.x ◽

1977 ◽

Vol 6 (5) ◽

pp. 529-532 ◽

Cited By ~ 3

Author(s):

S. JARAMILLO ◽

G. ANHORN ◽

F. SCHUNTER ◽

P. WERNET

Keyword(s):

Gene Dosage ◽

Dosage Effect ◽

Gene Dosage Effect ◽

Apparent Lack

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Peripheral T-cell lymphomas unspecified presenting in the skin: analysis of prognostic factors in a group of 82 patients

Blood ◽

10.1182/blood-2002-07-1960 ◽

2003 ◽

Vol 102 (6) ◽

pp. 2213-2219 ◽

Cited By ~ 161

Author(s):

Marcel W. Bekkenk ◽

Maarten H. Vermeer ◽

Patty M. Jansen ◽

Ariënne M. W. van Marion ◽

Marijke R. Canninga-van Dijk ◽

...

Keyword(s):

T Cell ◽

Cell Size ◽

Cell Lymphoma ◽

Large Cell ◽

Skin Lesions ◽

T Cell Lymphoma ◽

Peripheral T Cell Lymphoma ◽

T Cell Lymphomas ◽

Nor Phenotype ◽

Peripheral T Cell Lymphomas

Abstract In the present study the clinicopathologic and immunophenotypic features of 82 patients with a CD30– peripheral T-cell lymphoma, unspecified, presenting in the skin were evaluated. The purpose of this study was to find out whether subdivision of these lymphomas on the basis of cell size, phenotype, or presentation with only skin lesions is clinically relevant. The study group included 46 primary cutaneous CD30– large cell lymphomas and 17 small/medium-sized T-cell lymphomas as well as 17 peripheral T-cell lymphomas with both skin and extracutaneous disease at the time of diagnosis. Patients with primary cutaneous small- or medium-sized T-cell lymphomas had a significantly better prognosis (5-year-overall survival, 45%) than patients with primary cutaneous CD30– large T-cell lymphomas (12%) and patients presenting with concurrent extracutaneous disease (12%). The favorable prognosis in this group with primary cutaneous small- or medium-sized T-cell lymphomas was particularly found in patients presenting with localized skin lesions expressing a CD3+CD4+CD8– phenotype. In the primary cutaneous T-cell lymphoma (CTCL) group and in the concurrent group, neither extent of skin lesions nor phenotype had any effect on survival. Our results indicate that peripheral T-cell lymphomas, unspecified, presenting in the skin have an unfavorable prognosis, irrespective of the presence or absence of extracutaneous disease at the time of diagnosis, cell size, and expression of a CD4+ or CD8+ phenotype. The only exception was a group of primary cutaneous small- or medium-sized pleomorphic CTCLs with a CD3+CD4+CD8– phenotype and presenting with localized skin lesions.

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