XVI International Botanical Congess

Taxa belonging to Solanaceae are among important medicinal plants growing wildly throughout Iran. The present article considers karyotypic characteristics of these taxa and considers their general trends of changes during species diversification. Forty-three taxa belonging to species and populations of the genera: 1-Datura 2-Withania 3-Physalis 4-Atropa 5-Lycium 6-Hyoscyamus and 7-Solanum were studied. Somatic chromosome numbers varied from 2n=24 to 2n=72. The highest mean chromatin length was observed in Lycium ruthenicum (Semnan) and the least in Hyoscyamus pusillus. The most symmetrical karyotype was observed in Solanum nigrum (Khozestan) and the least in H. tenuicaulis. Taxa studied varied significantly in chromosome size and karyotypic formulae. Pearson correlation showed the role of structural changes of chromosomes in species diversification. Increase in chromosome number showed a positive correlation with total chromatin length and a negative correlation with size of the longest, shortest chromosome and the mean chromatin length. Cluster and principal component analysis of karyological data showed distinctness of each genus in its karyological characteristics as they formed separate clusters, moreover diploid species were separated from polyploids and annuals from perennials. The most variable chromosome/chromosome arm among taxa studied were identified. Many new chromosome numbers are reported.