The Control of Elongation in Callitriche Shoots by Environment and Gibberellic Acid

Abstract

Gibberellic acid (GA) was found to stimulate internode expansion in floating rosettes of the aquatic, Callitriche stagnalis. Treated shoots resembled those normally produced from submerged apices. The environmental factor which controls the growth of untreated floating rosettes was investigated, and found to be loss of water by transpiration. The morphological effects of different concentrations of GA are described. The similarity is pointed out between environmental dwarfing in Callitriche and genetic dwarfing in Pisum.