Estimation of DNA content and genome size of some orchids using flow cytometry

Flow cytometry technique is used extensively in plant sciences to reveal the deviation of genomic size to better identify or resolve the closely related organisms or groups. In this study, extracted nuclei from the leaf tissue of ten Dendrobium species were analyzed for their DNA content. A flow cytometer was used to measure DNA content after extracting and specific staining of nuclei. Direct comparison was performed using chicken erythrocyte nuclei (1C DNA = 1.25 pg) as a standard. The calculated amount of DNA content showed the variation in the amount, ranging from 3.78 to 8.75pg, equivalent to a genomic size of 1852.20 to 4287.50 Mbp, respectively. There was no correlation between elevation and quantity of genome of studied Dendrobium species. It was observed that the quantity of a particular species DNA was inversely proportional to the size of their flowers and positively correlated with the plant height and leaf length. An ANOVA test among the four variables was performed and to identify the subsets that were distinct from one another, we performed Tukey’s HSD test. A pair-wise comparison was performed and among the six compressions, only the stem length significantly differed (mean = 97.873, p< 0.001) from other three variables.