Abstract
Autotetraploidy was induced in Phlox drummondii by treatment of shoot apices of seedlings with 0.5% emulsion of colchicine in lanolin. Autotetraploid plants were found to show gigantism, both at the cellular level as well as the organ level. Pollen mother cells of autotetraploid plants showed predominantly bivalents and quadrivalents. Although pollen abortion in autotetraploids was only slight, seed set of such plants was markedly reduced. Possible mechanisms for the reduced seed set are discussed.
