Poster: Late and Moved Abstracts

Abs # 966: Long-distance signaling in plants: Graft transmission of a floral stimulant derived from CONSTANS

Presenter:	Ayre, Brian G., bgayre@unt.edu
Authors	Ayre, Brian G. (A) (B)  Turgeon, Robert  (B)
Affiliations:	(A): University Of North Texas, Department of Biological Sciences (B): Cornell University, Department of Plant Biology

Photoperiod is perceived by leaves, and in many species influences the transition to reproductive growth through long-distance signaling. CONSTANS (CO) mediates between photoperiod perception and the transition to flowering in Arabidopsis thaliana. To test its role in long-distance signaling, CO was expressed from a promoter specific to the companion cells of minor veins in mature leaves. Expression in these tissues at the inception of the translocation stream accelerated flowering at the apical meristem under non-inductive (short-day) conditions. Grafting plants with different flower-timing phenotypes demonstrated that minor-vein expression of CO substituted for photoperiod in generating a mobile flowering signal. Our results suggest that a CO-derived signal(s) fits the definition of the hypothetical floral stimulant, florigen.