Interspecific Chromosomal and Genome Size Variations in In Vitro Propagated Willow Herb (Epilobium spp.) Medicinal Plant

The genus Epilobium, belonging to the family Onagraceae, is an endemic Iranian medicinal plant that has illustrated a vast variety of pharmacologically important metabolites. The cytological characteristics of eight species collected from different regions of Iran were assessed for the first time. All species analyzed were diploid, six species (E. hirsutum, E. parviflorum, E. roseum, E. algidum, E. anatolicum, and E. confusum) had 2n=2x=36 chromosomes, except for two species (E. frigidum, E. lanceolatum) had 2n=2x=38 chromosomes with unequal in size. The mean chromosome length of all species was 0.53 µm, ranging from 0.46 to 0.64 µm. Propidium iodide (PI) and Solanum lycopersicum cv. Stupicke (2C DNA=1.96 pg) as an internal standard were used for flow cytometric survey of genome size and the levels of ploidy. The mean genome size (2Cx DNA) of all species was 0.86 pg, varied from 0.74 to 0.90 pg, confirming inter-specific variation and revealing considerable variation in genome size within each species. Valuable information on cytogenetics can be used in some research fields, including polygenetic analysis, taxonomic relationships, evolutionary characteristics, ecology, plant growth, and development of plant breeding.