EFFECTS OF EXOGENOUS AMINO ACIDS ON THE FLOWER AND FROND PRODUCTION IN DUCKWEED, LEMNA GIBBA G3

Abstract

1. Twenty usual amino acids examined were shown to be divided into two groups with respect to their actions on the flower formation (A) and frond multiplication (B) in a long-day duckweed, L. gibba G3. Amino acids of the first group (e.g., arginine) inhibited A without preventing B, and those of the second group (e.g., lysine) inhibited both A and B. The inhibition of flower formation was always the greatest when amino acid was applied at the induction period. 2. The floral inhibition by arginine applied at the induction period was partially or wholly reversed by the simultaneous addition of other amino acid (especially lysine) or by one additional long day. The inhibitions by lysine, however, were not reversed by arginine. 3. It was discussed that the terminal step(s) of photoperiodic induction process might depend largely on the relative in vivo concentrations of amino acids.