Photo-induced changes in proteins associated with floral induction in Amaranthus.

A. caudatus f. albiflorus, A. caudatus f. caudatus and A. tricolor var. tristis are qualitative SD plants with photo-inductive requirements of six, three and five, 8-hr photoperiodic cycles, respectively, for macroscopic inflorescence initiation. The total protein content gradually increased in both stem and leaves with an increasing number of inductive photoperiodic cycles. In both stem and leaves of all three plant types, two electrophoretically separable new water-soluble protein bands appeared with completion of their respective photo-inductive requirements for inflorescence initiation. In the stem of A. caudatus f. caudatus, a third band appeared after the plants had received only a single SD cycle. The new proteins formed concurrently with photoperiodic floral induction differed electrophoretically from plant to plant even though all plants used in the experiment were short-day plants and closely related taxonomically.