Chemical Stimulation of Germination Rate in Aged Tomato Seeds1

The germination rate of 10-year-old seeds of tomato, Lycopersicon esculentum Mill., line Mo. 17-St-23 was significantly increased by continuous soak treatments of GA 3 (0, 10 ppm) + kinetin (1, 10, 50 ppm) + KNO 3 (.01 M). Germination percentages 10 days after start of treatment, however, did not differ from those of untreated seeds. GA-induced increases in soluble sugars and in protein hydrolysis, increases in ribonuclease activity in both GA 3 and kinetin-treated seeds, and increased cytochrome oxidase activity with KNO 3 treatment were observed, suggesting that these chemicals speeded germination by correcting enzymatic and substrate deficiencies at the initial stages of germination.