Osman Gedik

Karyological studies on the annual members of the genus Carduus L. (Asteraceae, Cardueae) from Turkey

The somatic chromosome numbers and detailed morphometric properties of eight of the nine annual Turkish Carduus L. taxa were examined. The somatic chromosome numbers were 2n = 2x = 22 in C. rechingerianus Kazmi; 2n = 2x = 28 in C. argentatus L., C. acicularis Bertol. and C. pycnocephalus L. subsp. albidus (M. Bieb.) Kazmi; 2n = 2x = 34 in C. pycnocephalus subsp. arabicus (Jacq. ex Murray) Nyman and subsp. breviphyllarius P. H. Davis; 2n = 2x = 50 in C. nervosus K. Koch.; and 2n = 2x = 62 in C. pycnocephalus subsp. pycnocephalus. Karyotype analysis indicated that chromosomes of the Carduus taxa generally have centromere median region (m), submedian region (sm), and rarely median point (M) of the chromosome. A pair of satellite chromosomes (sat-chromosome) was observed in C. pycnocephalus subsp. breviphyllarius. The findings for each of the analysed taxa are compared with the results of previous studies. The chromosome number and morphology of C. nervosus, C. rechingerianus, C. argentatus, C. pycnocephalus subsp. arabicus and subsp. breviphyllarius are newly reported here.

Taraxacum bellidiforme ve Taraxacum revertens Endemik Türlerinin Karyolojik Yönden Araştırılması

Taraxacum Wiggers. cinsine (Asteraceae) ait olan endemik iki turun ( T. bellidiforme Van Soest., T. revertens G.Hagl. ) kromozom sayisi ve morfolojisi karyolojik teknikler kullanilarak arastirildi. Bitki ornekleri 2013 yilinda dogal habitatlarindan toplandi. Calisilan bu turlerde temel kromozom sayisi x= 8 dir. Turlerin kromozom sayilari; T. bellidiforme 2n=24, T. revertens 2n=24 ve 2n=32 olarak bulundu. Turlere ait kromozomlarin noktali median (M), median (m), submedian (sm) sentromerli oldugu gozlendi. Bu turlerin bazi kromozomlarinda satellit goruldu.

Cıva’nın Allium sativum’ un Kök Ucu Hücreleri Üzerindeki Mitotik Etkileri

In this study, the effects of mercury (HgCl2) one of the significant environmental pollutant, on mitotic divisions of the root tip cells of garlic (Allium sativum) were investigated. Different concentrations (0.015625, 0.03125, 0.0625, 0.125, 0.250, 0.500, 1.000 ve 2.000 mM Hg+2) of mercury were applied. It was observed that there are no significant differences in the germination of seeds that exposed to low mercury concentrations. On the other hand, at higher concentrations of mercury inhibited germination and root growth was stoped above 0.250 mM concentrations. In addition, root growth was inhibited according to the control group at all concentrations. In parallel to the increase of the mercury concentrations cell division was decreased, several mitotic anomalies such as, lagging chromosomes, multipolar anaphases, chromosome bridges andgranulation were increased