INTERACTION OF GIBBERELLIN, KINETIN AND POTASSIUM NITRATE IN THE GERMINATION OF LIGHT-SENSITIVE TOBACCO SEEDS

Abstract

1. The effects of gibberellin, kinetin, potassium nitrate, and their interactions in the germination of light-sensitive tobacco seeds were studied. 2. Gibberellin was very effective in inducing the dark germination of tobacco seeds, and a linear relation was found to exist between the germination rate and the concentration of gibberellin if a suitable temperature was chosen for germination. This linear relation was, however, changed by illumination and by a raised temperature in the manner that the germination on lower concentrations of gibberellin was increased by the former and decreased by the latter. 3. Kinetin was effective in promoting the tobacco seed germination only when the seeds were irradiated. This light effect was, however, limited only to the longer wavelengths in the visible region. The red effect was found to be reversed by infra-red irradiation under the influence of kinetin. 4. The combination of gibberellin and kinetin was synergistic in promoting the tobacco seed germination both in the light and in the dark, whereas the combination of potassium nitrate and gibberellin or kinetin was synergistic only in the light.