Cytogenetic and Flow Cytometry Analysis of Iranian Rosa spp

Since the ploidy level and nuclear DNA amounts are less exposed to natural selection than most morphological traits, and are more stable in the stages of evolution, they are used to study variation among different species. In order to study the diversity of Iranian Rosa spp., chromosome counting and flow cytometry (FCM) analyses were carried out on 10 species collected from different parts of the country. For each plant, cuttings were rooted and young leaves were collected. Root tips were pretreated in 8-hydroxyquinolin, fixed in Lewitsky solution and macerated in cellulase. Chromosome number and ploidy level of the investigated species ranged from diploid (2n = 2x = 14) to hexaploid (2n = 6x = 42). FCM analysis was conducted with propidium iodide (PI) on R. moschata, R. beggeriana, R. persica, R. foetida, R. hemisphaerica, R. pimpinellifolia, R. canina, R. boissieri, R. orientalis and R. pulverulenta. The mean 2C-value of different species showed a varying degree from 0.83 pg (s.d. ± 0.08 pg) in R. persica from subgenus Hulthemia to a four-fold higher amount of 3.54 pg (s.d. ± 0.08 pg) in R. pulverulenta from subgenus Rosa (=Eurosa). Finally, the PI measurements were compared with measurements obtained from 4', 6-diamidino-2-phenylindole (DAPI) staining, which indicated that DAPI ratios (p1/p2) were lower, but closely correlated (r = 0.98) with PI ratios (p1/p2). _____________________________________________________________________________________________________________

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