Karyotypic Studies of Two Thymus Species.

Mehrpur, S.; Mirzaie-Nodoushan, H.; Majd, Ahmad; Sefidkon, Fatemeh

doi:10.1508/cytologia.67.343

Cited by 7 publications

(6 citation statements)

References 5 publications

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“…The somatic chromosome number and details of the karyotypes of the studied populations, revealed that T. daenensis populations were diploid (2n=2x=30), while T. kotschyanus populations possessed two ploidy levels, diploid (2n=2x=30) and tetraploid (2n=4x=60). Similar researches performed in different populations of T. kotschyanus also showed that the basic chromosome number was x = 15 and ploidy levels are introduced as diploid and tetraploid (Morales, 1980(Morales, , 1989Mehrpur, 2002;Javadi, 2009). This object indicates that the stability level of ploidy of T. kotschyanus is unstable and the taxonomic position of this species makes it difficult.…”

Section: Resultssupporting

confidence: 54%

“…There are a lot of interesting cases of different ploidy levels within the same species (Stahl-Biskup and Saez, 2002). Mehrpur et al (2002) studied two species of the Thymus genus karyologically and taxonomically and found two ploidy levels diploid (2n=2x=30) and tetraploid (2n=4x=60) in T. kotschyanus species. The researches showed that the morphology and different components of essential oils in different species of Thymus are variable due to hybridization and polyploidization (Lopez-Pujol et al, 2004).…”

Section: Introductionmentioning

confidence: 99%

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Assessment of karyotypical variation among 16 populations of Thymus daenensis Celak and Thymus kotschyanus Boiss. species in Iran

Nasab¹

2012

Afr. J. Biotechnol.

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In order to study the cytological variation between Iranian native Thymus, karyotypes of two taxa (16 populations) from different geographic origins were presented. The ploidy level was different in populations belonging to T. kotschyanus (2x and 4x), but the same level was found (2x) in T. daenensis populations. According to intrachromosomal asymmetry, T. daenensis (10534) had the most asymmetrical and evolutionary karyotype and T. kotschyanus (10513) had the most symmetrical karyotype in all of the populations. While based on interchromosomal asymmetry, among diploid populations, T. daenensis (10535) and among tetraploid populations, only T. kotschyanus (10515) had the most asymmetrical karyotype. In terms of the Stebbins' system, the karyotype were of populations seizes 1A classes. The results of analysis of variance revealed significant differences between the populations based on all karyotypic characteristics (P<%1). The results of cluster analysis showed that populations of each species T. daenensis and T. kotschyanus have been grouped in separate cluster. The results seemed to provide enough genetic evidence to identify the species and useful data to clarify the interspecific relationships. Detailed karyotype analysis allows us to group the different populations and to specify their relationships.

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Section: Resultssupporting

confidence: 54%

Section: Introductionmentioning

confidence: 99%

Assessment of karyotypical variation among 16 populations of Thymus daenensis Celak and Thymus kotschyanus Boiss. species in Iran

Nasab¹

2012

Afr. J. Biotechnol.

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“…(1993), Markova and Goranova (1994, Mártonfi and Mártonfiova (1996), Boscaiu et al (1998), Tahiri et al (1998, Constantinidis et al (2002). Jalas (1948), Jalas and Kalev (1967) and Mártonfi and Mártonfiova (1996) and Mehrpure et al (2002) have discussed chromosomal evolution of Thymus regarding their basic chromosome numbers. This paper reports on chromosome characters of the resting, mitotic prophase and metaphase chromosomes in three species of Thymus collected in Russia and Mongolia by our field expedition.…”

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confidence: 99%

A comparison of chromosome characters in three species of Thymus (Lamiaceae) collected in Russia and Mongolian Altai

et al. 2008

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ABSTRACT. Characters of the resting, the mitotic prophase and metaphase chromosomes in three species of Thymus were studied. The species studied had commonly resting chromosomes of the complex chromocenter type and mitotic prophase chromosomes of the proximal type. Thymus mongolicus showed the chromosome numbers of 2n=26 and 27 and T. przewalskii and T. roseus showed the chromosome number of 2n=26. The chromosome number of 2n=26 for T. przewalskii and that of 2n=27 for T. mongolicus were reported here for the first time and that of 2n=26 for T. roseus and T. mongilicus verified the previous reports. The chromosome number of 2n=27 for T. mongolicus seemed to have one B-chromosome as 2n=26+1B with respect to the existence of a peculiar heteropycnotic body at resting stage and high pollen stainability. Three species were commonly placed in the diploid level if the basic chromosome numbers of x=13 was accepted. Their karyotypes at mitotic metaphase were quite similar to each other regarding chromosome sizes, chromosome types according to the centromeric position and mono-modality of chromosome lengths from the longest to the shortest chromosomes except for satellite sizes. Thymus L., the Lamiaceae (Labiatae) is small subshrub plants and consists of approximately 400 species (Willis 1982). They are distributed in the temperate zone of the Eurasian continent, mainly in the Mediterranean region (Willis 1982) and grow in diabase, serpentine and calcareous rocks, limestone, in cracks rocks, on a bank, steppe, on sandy soils, xerophilous grassland, on loessic slopes and along road sides. Thymus has always been taxonomically problematic group and views concerning the taxonomic definition of the forms are extremely varied. It produces some natural hybrids. Plants of the genus is often cultivated and propagate to extract the aromatic ethereal oil and flavouring. KEYWORDS:The first cytological observation in Thymus was counting and documenting the chromosome number: 2n=24 in T. serpyllum reported by Löve and Löve (1942). Then, many more researchers have found at least 50 different chromosome numbers from 2n=14 of T. seravschanicus to 2n=90 of T. zygioides var. lycaonicus. They also have found aneuploidy in T. longedentatus as well as autoploidy in about 170 taxa included 139 species, 17 subspecies, 12 varieties and two hybrids by Löve and Löve (1942), Saaremaa (1947), Jalas (1948), Jalas and Kaleva (1966Kaleva ( , 1967, Trela-Sawicka (1968, 1970, Gogina and Svetozarova (1972), Gurzenkov (1972), Lee (1972), Jalas and Uotila (1976), Krogulevich (1978), Arrigonia et. al. (1980, Bir and Saggoo (1980), ElenaRoselló (1980), Morales Valverde (1980, 19861986a, 1990, Astanova (1981), Hruška and Bellomaria (1982), Fernandes and Leitao (1984), Funamoto et. al. (1993), Markova and Goranova (1994, Mártonfi and Mártonfiova (1996), Boscaiu et al. (1998), Tahiri et al. (1998, Constantinidis et al. (2002). Jalas (1948), Jalas and Kalev (1967) and Mártonfi and Mártonfiova (1996) and Mehrpure et al. (2002) have discussed chromosomal evolutio...

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“…Their collection sites had only a minor difference in length and latitude. Mehrpur et al [25] . reported various chromosome numbers in T. kotschyanus from Mianeh and Tabriz (2 n =30) and Sirachal (2 n =60).…”

Section: Resultsmentioning

confidence: 99%

Variation in Phytochemical, Morphological, and Ploidy Levels of Iranian Thymus Species

Tohidi

Rahimmalek

Arzani

2021

Chemistry & Biodiversity

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Thymus is one of the most important genera of the Lamiaceae family. This work was performed to assess inter and intra species variation, which is an indispensable prerequisite for the selection and the exploitation of the germplasm, using yield, secondary metabolites, and ploidy level criteria. Nineteen Iranian populations belonging to 11 Thymus species which includes T. vulgaris were used in this study. The results of cytological observations on the 19 populations revealed the three root‐tip chromosome numbers of 2n=2x=30, 2n=4x=56 or 60 (diploid and tetraploid). This study also presents the results of a two‐year field experiment that evaluates the agronomic and morphology of the 19 populations of Thymus spp. Cluster analysis grouped the populations into six groups and explained the relationships among ploidy levels, morphological traits, and essential oils (EOs). In general, diploid species belonged to the thymol chemotype, whilst carvacrol chemotype consistently dependent on the gene‐dosage effect. Thymus migricus, T. daenensis‐2, T. serpyllum, and T. trautvetteri populations with diverse thymol background were the best selection as the parents to improve thymol in a breeding program. Moreover, dry and fresh weight criteria can be used to improve EO content in thyme. Achieving this goal would be expected by crossing T. migricus and T. daenensis‐2. Finally, providing relevant information on the ploidy level of Thymus species, with emphasis on morphology and EO components variations, may be recommended for the selection of populations or species to improve bioactive components as well as morphological traits in future breeding programs.

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Karyotypic Studies of Two Thymus Species.

Cited by 7 publications

References 5 publications

Assessment of karyotypical variation among 16 populations of Thymus daenensis Celak and Thymus kotschyanus Boiss. species in Iran

Assessment of karyotypical variation among 16 populations of Thymus daenensis Celak and Thymus kotschyanus Boiss. species in Iran

A comparison of chromosome characters in three species of Thymus (Lamiaceae) collected in Russia and Mongolian Altai

Variation in Phytochemical, Morphological, and Ploidy Levels of Iranian Thymus Species

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