ACTIVITIES OF AUXIN POLAR TRANSPORT IN INFLORESCENCE AXES OF FLOWER MUTANTS OF ARABIDOPSIS-THALIANA - RELEVANCE TO FLOWER FORMATION AND GROWTH

Relationships between the activity of auxin polar transport and flower formation were studied using several flower mutants of Arabidopsis th aliana, The activity of auxin polar transport in the upper portion of inflorescence axis of wildtype plants of Arabidopsis thaliana was sign ificantly lower than that of the basal part. The activities of auxin p olar transport in the upper portion of inflorescence axes of apl and c lv1 mutants were significantly higher than that of wildtype plant Howe ver, those of other flower mutants tested, ap3-1, ag, pi, Fl-40, Fl-54 , Fl-89 and pin-formed, were extremely low as compared with that of wi ld one, We got some evidence that the reduction of the activity of aux in polar transport is concerned with the growth and development of pla nts, We could mimic it by the removal of all flowers and pods includin g mature or immature seeds, Moreover, artificial pollination in ap3-1 and pi mutants, in which no seeds are found naturally, resulted in the partial recovery of the activity of auxin polar transport in inflores cence axis. Considering these results in this study together with the fact that inhibitors of auxin polar transport generated almost same di sruptions of pin-formed or pinoid mutants which normally had no flower s in inflorescence axis (Okada et al. 1991, Ueda et al, 1992, Bennett et ai,1995), the. system of auxin polar transport and its activity in inflorescence axis seems to be essential for the development of flower bud in early stage of Arabidopsis thaliana, and the activity of auxin polar transport is also regulated by the formation of flowers and see ds in inflorescence axis.