The induction of flowering by one long day (LD) in the grass Lolium temulentum is most closely mimicked by application of the gibberellins (GAs) GA5 or GA6, both of which occur naturally. These gibberellins promote floral development but have little effect on stem elongation. Endogenous GA5 and GA6 contents in the shoot apex double on the day after the LD and, for GA5 (and we presume for GA6 as well) reach a concentration known to be ...
