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Dive into the research topics where Hasan Akan is active.

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Featured researches published by Hasan Akan.


Plant Systematics and Evolution | 2008

Seed morphology and its systematic implications for genus Astragalus L. sections Onobrychoidei DC., Uliginosi Gray and Ornithopodium Bunge (Fabaceae)

Cem Vural; Murat Ekici; Hasan Akan; Zeki Aytaç

Forty-eight species of Astragalus L. sections Onobrychoidei DC., Uliginosi Gray and Ornithopodium Bunge (Fabaceae) in Turkey were studied in order to describe and investigate their seed morphologies and to evaluate the diagnostic value of this character using a stereoscopic microscope and a scanning electron microscope (SEM). SEM pictures of seeds were taken as a whole and in detail. The systematic implications of the findings are discussed. Six main seed types were observed. A key to identifying the different seed types is provided.


Caryologia | 2008

Karyomorphological studies on section Bucerates Boiss. of Trigonella L. (Leguminosae) from Turkey

Martin Esra; Hasan Akan; Murat Ekici; Zeki Aytaç

Abstract The Karyomorphology of all taxa of section Bucerates Boiss. genus Trigonella L. (Leguminosae) were made using Image Analysis System. The chromosome numbers of 14 taxa of Trigonella (2n = 16), T. fischeriana Ser. and T. monantha C.A.Meyer subsp. noeana (Boiss.) Hub.-Mor. (2n = 14), T. monantha C.A.Meyer subsp. monantha Verz. (2n = 16, 28, 30) and T. orthoceras Kar. & Kir. (2n = 16, 46) were counted. B chromosomes were observed on T. arcuata C.A.Meyer. and there were two chromosomes with a satellite in T. crassipes Boiss. In the section Bucerates, 12 taxa of Trigonella showed tetraploidy, with 2n = 32 and two taxa of Trigonella had hexaploidy (2n = 48). The range of chromosome length ranged from 3.26 μm to 0.56 μm. Whereas T. orthoceras had the longest chromosome length, T. monantha subsp. monantha had shortest.


Caryologia | 2009

Karyological study on six Trigonella L. species (Leguminosae) in Turkey

Yilmaz Aykut; Esra Martin; Fatma Ünal; Hasan Akan

Abstract — In this study, karyotype analyses of the six species of Trigonella L. were examined. Chromosome lengths were determined between 1.29–1.74 μm in Trigonella astroites Fischer & C.Meyer, 1.06–1.44 μm in Trigonella fscheriana Ser., 1.67–2.59 μm in Trigonella velutina Boiss., 0.98–1.49 μm in Trigonella cretica (L.) Boiss., 1.16–1.81 μm in Trigonella coerulescens (M.Bieb.) Hal., 0.99–1.72 μm in Trigonella procumbens (Bess.) Rchb., respectively. All species are diploid with 2n = 14,16 and 18 chromosomes and the karyotypes of all species consist of metacentric chromosome pairs. Trigonella velutina has only satellites on the long arms of chromosome 2 and 6. The karyotype analysis of these species was frst time counted in Turkey.


African Journal of Agricultural Research | 2012

Comparative seed morphology of Trigonella L. species (Leguminosae) in Turkey

Talip Çeter; N. Munevver Pinar; Hasan Akan; Murat Ekici; Zeki Aytaç

Seeds morphology of 37 taxa of Trigonella L. from various regions in Turkey were examined with a scanning electron microscope and light microscope. Based on seed features such as shape, colour and surface ornamentation pattern, 7 morphological types were recognized. Type I have scabrated seed surface and this is only observed in section Samaroideae, Type II have verrucated seed surface, Type III have rugulated seed surface and a further classification has been made on the basis of vart, as those rugulate-verrucate (Trigonella lunata in section Lunatae, Trigonella isthmocarpa and Trigonella rhytidocarpa in section Isthmocarpae and Trigonella gladiata in section Foenum-graecum) and granule as those rugulate-granulate (only Trigonella carica in section Bucerates). Type IV is show ruminated seed surface. Type V have aculeated seed surface. This ornamentation are observed in section Cylindricae, section Reflexae and section Biebersteinionae and Section Cylindricae. Type VI are the ones with ridged-tuberculated-verrucated seed surface and this type has been observed in the section Bucerates, Reflexae, Uncinatae and some species of Foenum-graecum. Type VII have tuberculated seed surface and this is only observed in section Capitata. The different seed types are described, illustrated compared and their taxonomic importance is discussed. The seed surface ornamentations of taxa shows considerable variations. This character have importance in systematic discrimination of taxa. Key words: Trigonella, Fabaceae, seed morphology, scanning electron microscopy (SEM), light microscopy (LM), Turkey.


Comparative Cytogenetics | 2011

Karyotype analyses of ten sections of Trigonella (Fabaceae).

Esra Martin; Hasan Akan; Murat Ekici; Zeki Aytaç

Abstract Karyotypes of ten sections of genus Trigonella Linnaeus, 1753 (Fabaceae) from Turkey were investigated. Somatic chromosome numbers of examined species were determined as 2n=14 and 16. The karyotype analyses of the species were carried out and somatic chromosome numbers of Trigonella plicata Boiss., 1872, Trigonella brachycarpa (Fisch.) Moris, 1833, Trigonella rostrata Boiss., 1872, Trigonella lunata Boiss., 1843, Trigonella isthmocarpa Boiss. et Balansa 1856, Trigonella rhytidocarpa Boiss. et Balansa, 1859, Trigonella spicata Sibth. et Sm., 1813, Trigonella cephalotes Boiss. et Balansa 1856, Trigonella capitata Boiss., 1843 and Trigonella gladiata Steven, 1808 were reported for the first time. Two pairs of satellite metaphase chromosomes were observed in Trigonella cariensis Boiss., 1843 and one pair in Trigonella lunata.Moreover, 2 B-chromosomes were found only in Trigonella procumbens Rchb., 1830 among all studied species. The aims of this study are to provide karyological data for a significant pool of the taxa, to show differences among them in the number, size and morphology of somatic chromosomes, to verify previous reports or represent numbers which are different from those cited previously.


Botanical Journal of the Linnean Society | 2003

A new species of Centaurea (Asteraceae: sect. Psephelloideae) from Turkey

Ismail Türkoǧlu; Hasan Akan; Şemsettin Civelek


Vegetation History and Archaeobotany | 2011

The climate of the Younger Dryas as a boundary for Einkorn domestication

Sylvi Haldorsen; Hasan Akan; Bahattin Çelik; Manfred Heun


Turkish Journal of Botany | 2005

Check-List of the Genus Colchicum in the Flora of Turkey

Hasan Akan


Botanical Journal of the Linnean Society | 2003

New species of Astragalus (sect. Alopecuroidei: Leguminosae) from Turkey

Hayri Duman; Hasan Akan


Turkish Journal of Botany | 2004

Some Morphological and Anatomical Investigations on Autumn Species of Crocus L. Occurring in Şanlıurfa

Hasan Akan; İsmail Eker

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İsmail Eker

Abant Izzet Baysal University

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