Induction of Autotetraploidy and Characterization of the Effects of Genome Duplication on Native Ornamental Species Monarda punctata and Monarda fistulosa (Lamiaceae)

Lamina, petiole and nodes of Monarda punctata and M. fistulosa were tested to develop an in vitro propagation method using a range of seven BAP concentrations (0-25µM). Nodes produced significantly more shoots in both species and the optimal hormone concentration was 25µM. Unrooted plantlets were acclimatized using a rooting powder and directly placing them into a soil mixture. To induce autotetraploidy, oryzalin and trifluralin were added into the medium in a range of eight concentrations (0-120µM) and nodes were exposed for 1, 3 or 6 days. A total of 43 M. punctata and 124 M. fistulosa tetraploids were identified and significant correlations between stomatal length and ploidy level were found. Finally, in M. punctata TPC was increased with ploidy level while %AA was unaffected. M. fistulosa had a decrease in TPC and %AA with an increase in ploidy level. However, one autotetraploid had a significant increase in TPC and %AA.