ARABIDOPSIS GENES THAT REGULATE FLOWERING TIME IN RESPONSE TO DAY-LENGTH

Flowering of the model plant species Arabidopsis thaliana is influence d by the length of time that the plants are exposed to light (photoper iod) during each day. We have studied mutations that reduce ol abolish the promotion of flowering that is normally seen under long photoperi ods. One of the genes affected by one of these mutations has been clon ed, and is predicted to encode a transcription factor. We are also stu dying mutations that prevent the delay in flowering that is normally f ound when plants are grown under short photoperiods, and the genes aff ected by some of these mutations are being cloned. Mutations causing e arly and late flowering have also been combined in double mutants, and the phenotypes of these plants suggest how these different types of f lowering time genes might interact.