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

1. The effects of gibberellin, kinetin, potassium nitrate, andtheir interactions in the germination of light-sensitive tobaccoseeds were studied. 2. Gibberellin was very effective in inducing the dark germinationof tobacco seeds, and a linear relation was found to exist betweenthe germination rate and the concentration of gibberellin ifa suitable temperature was chosen for germination. This linearrelation was, however, changed by illumination and by a raisedtemperature in the manner that the germination on lower concentrationsof gibberellin was increased by the former and decreased bythe latter. 3. Kinetin was effective in promoting the tobacco seed germinationonly when the seeds were irradiated. This light effect was,however, limited only to the longer wavelengths in the visibleregion. The red effect was found to be reversed by infra-redirradiation under the influence of kinetin. 4. The combination of gibberellin and kinetin was synergisticin promoting the tobacco seed germination both in the lightand in the dark, whereas the combination of potassium nitrateand gibberellin or kinetin was synergistic only in the light. (Received November 1, 1960; )