Obligate requirement of salicylic acid for short-day induction of flowering in a new duckweed, Wolffiella hyalina 7378

Abstract

Wolffiella hyalina 7378, a member of the Lemnaceae, does not flower in the basal media of Bonner-Devirian, Hoagland, Hutner (½ strength), M medium of Hillman or Pirson-Seidel under either long or short day photoperiodic regimes. Well-known chelating agents, such as EDTA, EDDHA and 8-hydroxyquinoline, which have been shown to significantly influence flowering in other members of the Lemnaceae, also do not show any effect in this strain. It is, however, noteworthy that W. hyalina 7378 flowers profusely under a short-day photoperiodic schedule of 8 h light and 16 h darkness provided that 10^-5 m salicylic acid is supplemented to modified Bonner and Devirian medium. The critical daylength of W. hyalina 7378 is 13 h. Further, at least two inductive photocycles are required for initiation of flowering. As to the mechanism of SA action, it appears that SA effect on flowering is hormonal in nature rather than due to chelation of metal ions.