An Old Collection of Mutants of Pharbitis nil -A New Experimental Material for Flower Morphogenesis-

Abstract

Summary: An old collection of mutants of Pharbitis nil is proposed to be used as a new experimental material for the study of flower morphogenesis. Most of the mutants were isolated over100years ago, and recorded in colored woodblock printings. The mutants were later analyzed from the view point of modern plant genetics. The author recently observed some of them. With the knowledge of the reported genetical analysis and the present anatomical observation, the mutants appeared in the old woodblock paintings were classified into seven groups. These mutations seem difficult to be explained through the ABC model. Many of the genes involved in the P. nil flower morphology has a characteristics of pleiotropism, that is, some mutations accompany with dwarfism, reduced apical dominance, narrow- or curled-leaved phenotype. The fact that the flower morphogenesis cannot be explained through the ABC model suggests that some new genes with an unreported function regarding flower morphogenesis could be isolated. If the morphology of flower, leaf and stem is analyzed simultaneously, taking the p leiotropism advantage, the common mechanism of morphogenesis may be clarified.