Abstract
Photoperiodic induction of flowering requires light perception in leaves, followed by transmission of mobile signal from leaves to the apex, where floral meristems are initiated.
In Arabidopsis, floral pathway integrator FT acts mainly in the photoperiod pathway through transcriptional regulation by CONSTANS. FT encodes a 20kD protein of the PEBP/RKIP family and is expressed in vasculature of cotyledon and leaf where light is perceived. Recently, it was reported that FT mRNA is transported from leaf to the apex.
To examine whether the effect of FT to promote flowering is transmissible across long distance, we performed micrografting experiments. Using 4-day-old seedlings, two-shoot, 'Y-shaped' grafts were assembled on hypocotyls of ft-1 recipient. We observed that flowering of ft-1 recipients was accelerated by grafting scion with functional FT (either endogenous gene or transgene). Whether FT promotes its own long-distance action is currently being investigated.
