Comparative Studies on Cellular Behaviour of Carnation (Dianthus caryophyllusLinn. cv. Grenadin) GrownIn VivoandIn Vitrofor Early Detection of Somaclonal Variation

Abstract

The present study deals with the cytological investigations on the meristematic root cells of carnation (Dianthus caryophyllusLinn.) grownin vivoandin vitro. Cellular parameters including the mitotic index (MI), chromosome count, ploidy level (nuclear DNA content), mean cell and nuclear areas, and cell doubling time (Cdt) were determined from the 2 mm root tip segments of this species. The MI value decreased when cells were transferred fromin vivotoin vitroconditions, perhaps due to early adaptations of the cells to thein vitroenvironment. The mean chromosome number was generally stable (2n=2x=30) throughout the 6-month culture period, indicating no occurrence of early somaclonal variation. Following the transfer to thein vitroenvironment, a significant increase was recorded for mean cell and nuclear areas, from 26.59 ± 0.09 μm2to 35.66 ± 0.10 μm2and 142.90 ± 0.59 μm2to 165.05 ± 0.58 μm2, respectively. However, the mean cell and nuclear areas ofin vitrogrownD. caryophylluswere unstable and fluctuated throughout the tissue culture period, possibly due to organogenesis or rhizogenesis. Ploidy level analysis revealed thatD. caryophyllusroot cells contained high percentage of polyploid cells when grownin vivoand maintained high throughout the 6-month culture period.