Morphological and stomatal guard cell characteristics of in vitro Kaempferia rotunda L. (Zingiberaceae) through colchicine induced polyploidy

Kaempferia rotunda L. was introduced to plant improvement programs by polyploidy induction for developing new ornamental gingers. In order to improve some characteristics of K. rotunda, tetraploid plants were induced by in vitro culturing young shoots of K. rotunda on gelrite modified MS medium supplemented with 0.2 % colchicine for 4 days. After incubation, all of the explants were transferred to culture on shoot multiplication medium and subcultured until M₁V₄ generation for chimera segregation. Ploidy determinations were made by flow cytometry analysis. Stomatal guard cell size, leaf thickness, and chloroplast numbers in the stomata of polyploid plants were significantly increased when compared with diploid plants. However, difference of stomatal index was not found in all polyploid plants. Two solid lines of tetraploid plants, normal green and variegated dwarf, were generated. The leaves of the normal green group were thicker and wider than those of diploid plants. In contrast, the variegated dwarf group showed smaller leaves with chlorophyll mutation.