FLOWERING IN DARKNESS IN ARABIDOPSIS-THALIANA

A modified method for studying the initiation of flowering in darkness (dark flowering, DF) in Arabidopsis thaliana has been developed, and the DF process has been examined with the aid of late-flowering mutant s. A majority of plants developed floral buds by the use of liquid-sha ken cultures in darkness. The late-flowering phenotype in gi and co mu tants and early-flowering phenotype in a hy2 mutant disappeared in DF. It was found that wild-type plants grown under DF conditions express light-regulated genes and develop appropriate leaf architecture, as do the light-grown plants, without the apparent differentiation of chlor oplasts. The shift experiments from darkness to light revealed the cri tical duration of growth in darkness for the initiation of DF. These r esults indicate that the DF process to the initiation of flowering is a mode of development distinct from that in light in Arabidopsis.