KARYOTYPE ANALYSIS OF SOME ONOBRYCHIS ( SAINFOIN ) SPECIES IN TURKEY ESRA

 In this study, karyotype analysis of the species of Onobrychis sp. was undertaken using the squash method. The results showed that the chromosome number of Onobrychis tournefortii (Willd.) Desv., O. gracilis Besser, O. hypargyrea Boiss. is 2n = 14 and O. argyrea Boiss. subsp. argyrea Boiss., 2n = 16. The karyotype formula of O. tournefortii (Willd.) Desv. is 4m+3sm, of O. hypargyrea Boiss. and O. gracilis Besser 3m+4sm, and of O. argyrea Boiss. subsp. argyrea Boiss. 2m+ 5sm+1 st.


INTRODUCTION
The Onobrychis genus is represented throughout the world with 162 species and in Turkey there are 52 species, 27 of which are endemic in Turkey (Aktoklu 1995).Studies on the chromosome number and morphology have been conducted on the Onobrychis genus.According to Abou-El-Enain (2002), the chromosome numbers of the genus Onobrychis are reported as 2n = 14, 28, 56, 16, 32, and 2 basic chromosome numbers, x=7 and x=8, are present in the genus.
The karyotype analysis and chromosome counting of Onobrychis tournefortii (Willd.)Desv., Onobrychis argyrea subsp.argyrea Boiss., Onobrychis hypergyrea Boiss., Onobrychis gracilis Besser.(the chromosome number of this last species was not counted) was conducted for the first time in the present study.

MATERIALS AND METHODS
The four Onobrychis specimens were collected and identified in 2005.Voucher specimens and seeds are being conserved in the Herbarium of Ankara University, Faculty of Agriculture, Department of Field Crops.These four species, endemic in Turkey, were collected from the following areas: Onobrychis tournefortii (Willd.)Desv., Nevşehir, Turkey, 38 In order to define the karyotype and chromosome number, the root tips of 2-3 day-old seedlings were used for accumulation of cells in metaphase as described by Elçi (1965).The roots were cut and kept for 12 h at 0ºC.Afterwards, the roots were determined in a 3:1 absolute alcohol, glacial acetic acid mixture for 30 min, hydrolyzed for 12 min in 1 N HCl at 60ºC and stained with Feulgen for 30 min the dark at room temperature before making the microscopic preparations.Only the roots of O. argyrea Boiss.subsp.argyrea Boiss.were stained with Aceto-Iron-Hematoxilin for 20 min at 30ºC (Zarifi 2004).Synchronized root tips were then squashed in 1% lactopropionic orcein for chromosome preparations as described by Busch et al. (1996).The counting of the chromosomes, measuring their lengths, and conducting the karyotype analysis, were performed using permanent slides which contain the chromosomes at the metaphase stage of mitosis.Photographs, enlarged 10x100, were taken using a camera attached to the microscope.Only the slides with a good spread, clearly observable morphologies and somatic root tips on the same plane were used.At least 8 complete metaphase figures with clearly distinguishable chromosomes were measured using LUCIA software and the average values of the relative sizes of the chromosomes and their arms were used to construct ideograms.The total chromosome length was measured with the computer system.The rules for numbering chromosomes within ideograms generally followed those used by Verma (1978), and Lavania and Sharma (1980).
Most of the cytological studies in the genus have concentrated on chromosome count.In this study, we determined the chromosome numbers and detailed measurements of four species of Onobrychis as 2n=14, 16 for the first time in Turkey.When the results provided from this study are compared with previous studies of the chromosome numbers of the Onobrychis genus, they do not show variation.Previous reports show that investigated members of Onobrychis have chromosomes with 2n=14, 16, 28, 32 (Ansariasl et al. 2001;Abou-El-Enain, 2002;Ansari et al. 2002;Hoşgören, 2006;Hatami and Nasırzadeh, 2007;Hesamzadeh Hejaji and Ziaeinasab, 2008).This study together with former results shows that the basic haploid chromosome numbers of Onobrychis may be n=7, 8.

Table 2 .
Detailed features of somatic metaphase chromosome of O. hypargyrea Boiss.

Table 3 .
Detailed features of somatic metaphase chromosome of O. gracilis Besser.