Leaf micromorphology of 19 Mentha taxa

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.

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

Genome ◽  
1989 ◽  
Vol 32 (4) ◽  
pp. 667-671 ◽  
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.

scholarly journals Links between environment and stomatal size through evolutionary time in Proteaceae

2020 ◽  
Vol 287 (1919) ◽  
pp. 20192876
Author(s):  
Gregory J. Jordan ◽  
Raymond J. Carpenter ◽  
Barbara R. Holland ◽  
Nicholas J. Beeton ◽  
Michael D. Woodhams ◽  
...  
Keyword(s):  
Guard Cell ◽  
Stomatal Density ◽  
Stochastic Modelling ◽  
Cell Length ◽  
Stomatal Index ◽  
Coordinated Development ◽  
Pavement Cell ◽  
Pavement Cells ◽  
Stomatal Size ◽  
Leaf Tissues

The size of plant stomata (adjustable pores that determine the uptake of CO 2 and loss of water from leaves) is considered to be evolutionarily important. This study uses fossils from the major Southern Hemisphere family Proteaceae to test whether stomatal cell size responded to Cenozoic climate change. We measured the length and abundance of guard cells (the cells forming stomata), the area of epidermal pavement cells, stomatal index and maximum stomatal conductance from a comprehensive sample of fossil cuticles of Proteaceae, and extracted published estimates of past temperature and atmospheric CO 2 . We developed a novel test based on stochastic modelling of trait evolution to test correlations among traits. Guard cell length increased, and stomatal density decreased significantly with decreasing palaeotemperature. However, contrary to expectations, stomata tended to be smaller and more densely packed at higher atmospheric CO 2 . Thus, associations between stomatal traits and palaeoclimate over the last 70 million years in Proteaceae suggest that stomatal size is significantly affected by environmental factors other than atmospheric CO 2 . Guard cell length, pavement cell area, stomatal density and stomatal index covaried in ways consistent with coordinated development of leaf tissues.

Micromorphologie des épidermes foliaires chez quelques espèces de Medicago

1983 ◽  
Vol 61 (12) ◽  
pp. 3461-3470 ◽  
Author(s):  
Catherine Damerval
Keyword(s):  
Guard Cell ◽  
Stomatal Density ◽  
Epidermal Cells ◽  
Cell Length ◽  
Leaf Epidermis ◽  
Trichome Density ◽  
Stomatal Index ◽  
Annual Species ◽  
Abaxial Epidermis ◽  
Stomatal Complex

The micromorphology of the abaxial epidermis of the first and sixth leaf has been studied in seven annual species of Medicago L. The pattern of the epidermal cells and of the stomatal complex does not allow differentiation of the taxa. Three main types of trichomes are recognized on the two foliar levels; their localization on the first leaf epidermis allows identification of five taxa out of seven. Four quantitative variables are also examined: stomatal density, trichome density, guard cell length, and stomatal index. The variable having the best discriminant value is the guard cell length on the first leaf. It is possible to identify each of the seven species by a combination of two features: the localization of the types of trichomes on the first leaf and the stomatal density on the sixth leaf.

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

1980 ◽  
Vol 58 (16) ◽  
pp. 1820-1831 ◽  
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.

Relationship between guard cell length and cold hardiness in wheat

1994 ◽  
Vol 74 (1) ◽  
pp. 59-62 ◽  
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

Development of matured hiPSCs-derived 3D cardiac tissue using ERR gamma agonist and mechanical stress and application for Hypertrophic Cardiomyopathy (HCM) model

2020 ◽  
Vol 41 (Supplement_2) ◽  
Author(s):  
Y Fujiwara ◽  
K Deguchi ◽  
Y Naka ◽  
M Sasaki ◽  
T Nishimoto ◽  
...  
Keyword(s):  
Mitochondrial Dna ◽  
Hypertrophic Cardiomyopathy ◽  
Mechanical Stress ◽  
Cell Size ◽  
Dna Content ◽  
Disease Model ◽  
Heart Tissue ◽  
Funding Source ◽  
Mitochondrial Dna Content ◽  
Mechanical Stretching

Abstract Introduction Tissue engineering using human induced pluripotent stem cells-derived cardiomyocytes (hiPSCs-CMs) is one of the potential tools to replicate human heart in vitro. Although there are many publications on 3 dimensional (3D) heart tissues (1), these tissues show fetal like phenotypes. For that reason, several maturation methods such as electrical stimulation and mechanical stress have been investigated (2, 3). However, these methods have been inadequate in differentiating fetal like phenotype tissue from adult tissues. Previously, we identified a novel compound, T112, which induced hiPSCs-CMs maturation from approximately 9,000 compounds using Troponin I1-EmGFP and Troponin I3-mCherry double reporter hiPSCs-CMs. This compound enhanced morphological and metabolic maturation of hiPSCs-CMs via estrogen-rerated receptor gamma activation Purpose We hypothesized that our novel compound, T112, in combination with mechanical stress could result in further maturation of 3D heart tissue. Therefore, our specific aim is to develop a novel maturation method applicable to genetic disease model of HCM using 3D heart tissue combined with T112. Methods We constructed 3D heart tissue mixed with fibroblast and double reporter hiPSCs-CMs by the hydrogel methods using Flex cell system®. We added T112 with or without mechanical stretching to 3D tissue from 7 to 15 days after 3D heart tissue was constructed. Then we measured maturation related phenotype such as sarcomere gene expression, mitochondrial DNA content and cell size. Results Similar to hiPSCs-CM, the addition of T112 to the constructed 3D heart tissue significantly increased TNNI3 mRNA compared to that of DMSO. Furthermore, T112 treated 3D heart tissue showed increased cell size and oblong shape. Next, in order to promote more maturation of 3D heart tissue, we performed mechanical stretching with the addition of T112. The combination of T112 with mechanical stretching showed higher expression of mCherry, a reporter protein for TNNI3 expression, and higher isotropy of sarcomere alignment in 3D heart tissue than that with the static condition. Furthermore, 3D heart tissue in the treatment of T112 with or without mechanical stretching showed higher mitochondrial DNA content compared to the respective DMSO controls. Interestingly, we applied this combination method to hiPSCs carrying MYH7 R719Q mutation which is known to cause hypertrophic cardiomyopathy, and the 3D heart tissue composed of cardiomyocytes derived from mutant iPSCs demonstrated increased sarcomere disarray compared to isogenic wild-type 3D heart tissue. Conclusion These results suggest that the combination of T112 and mechanical stretching promotes metabolic and structural maturation of 3D heart tissue and would be useful for creating a HCM disease model. Funding Acknowledgement Type of funding source: Private company. Main funding source(s): T-CiRA project, Takeda Pharmaceutical Company Limited

DNA-content of soil bacteria of different cell size

1989 ◽  
Vol 21 (6) ◽  
pp. 789-793 ◽  
Author(s):  
L BAKKEN ◽  
R OLSEN
Keyword(s):  
Cell Size ◽  
Dna Content ◽  
Soil Bacteria

DNA Content and Chromosome Number in Twenty–five Human Carcinomas

Oncology ◽  
1970 ◽  
Vol 24 (1) ◽  
pp. 48-57 ◽  
Author(s):  
J. Paulete-Vanrell
Keyword(s):  
Chromosome Number ◽  
Dna Content ◽  
Human Carcinomas
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