Tohru Hashimoto’s research while affiliated with Musashi University and other places

• Investigation was made on the influence of inorganic phosphate upon the germination of positively photoblastic tobacco seed (Nicotiana tabacum L. var. uirginica (AGDH.) COM. “Bright Yellow”) induced by GA3, GA3M, kinetin, red light, and ammonium salts of various organic acids. • Inorganic phosphate increases the GAs-induced germination, and inhibits the germination caused by ammonium citrate, while it does not influence the germination brought about by GA3M, kinetin, and red light. • The optimum pH for the GA3-induced germination lies in the acidic pH range, indicating that the undissociated form of GA3 is operative. The stimulatory effect of phosphate is, however, not ascribed merely to the pH control in the mediurr. Phosphate exerts some specific influence for which the presence of the free carboxyl group of GAs is required. • The observed contrasting effects of phosphate on the GA3-induced germination (i.e., acceleration), on the one hand, and on the ammonium citrate-induced germination (i.e., inhibition), on the other, were explained by assuming that the phosphate effects ultimately consist in accelerating the uptake of the carboxylic acid into the seeds. • GA3M also has an activity of inducing the germination of tobacco seed without light.

1) Effects on gibberellin induced dark germination of tobacco seed of pyruvic, acetic, citric, α-ketoglutaric, succinic, fumaric, malic and tartaric acids were examined in presence of NH4OH or KOH. 2) These acids accelerated the gibberellin action at acidic pH range, especially from pH 2.0 through 4.5. But when the seed of short storage length was used as the material, these acids accelerated the gibberellin induced dark germination at around pH 4.7, too. 3) Effects of these acids on dark germination of tobacco seed were studied in the presence of NH4OH or KOH. 4) Malic and tartartic acids induced dark germination in a wide pH range in the presence of NH4OH. The highest germination rate was observed at around pH4.8. 5) Pyruvic, acetic, citric, succinic and fumaric acids induced the dark germination at pH4.5 in the presence of NH4OH. These acids seemed to induce the dark germination mostly at around pH4.8. 6) The seed of short storage length seemed to have the ability to synthesize some compounds necessary for the induction of dark germination from an organic acid and NH4OH at around pH4.8.

1) The effect of ammonium nitrate, ammonium phosphate, ammonium sulphate, ammonium chloride, potassium nitrate, potassium phosphate, potassium chloride and potassium sulphate on the dark germination inducing action of gibberellin were studied. These salts promote the action of gibberellin, even though they have no germination inducing action by themselves. 2) Among these eight compounds, the former six have remarkable promoting effect on gibberellin action. 3) Potassium phosphate and ammonium phosphate accelerate the gibberellin action remarkably in acidic pH range, especially in the concentration range from M/20 to M/10. 4) Influence of pH on the effect of the salts on the dark germination inducing action of gibberellin is quite remarkable, when potassium nitrate, ammonium chloride, potassium phosphate and ammonium phosphate are used. 5) Potassium-, nitrate-, ammonium-, and phosphate-ions seem to act in different ways.

Comparative effectiveness of gibberellins A1, A2, A3 and A4 (GA1, GA2, GA3and GA4) in promoting the elongation of rice seedlings, in accelerating the expansionof green radish leaf disks and of etiolated bean leaf disks, and in inducing the darkgermination of tobacco seeds, was investigated. These four gibberellins were allactive in every investigated phenomenon, but different in comparative activity. Inthe leaf expansion and the tobacco seed germination, unlike in the elongation of riceseedlings, GA4 was especially active and new orders of effectiveness such as GA4_??_GA3>GA1>GA2 or GA4_??_GA1>GA3>GA2 were observed. It appears that gibberellinsshow different effectiveness with different physiological phenomena