1959 Volume 28 Issue 3 Pages 143-148
[Correction] Journal of the Japanese Society for Horticultural Science Vol.29 No.2 (1960) pp.100-100
1. The present study was carried out to confirm the effect of gamma radiation on the inhibition of sprouting of onions during the storage and to investigate the physiological changes following the treatment. Onion bulbs were irradiated with the doses of 3000, 7000, and 12000 r. soon after the harvest (June 28) and at the presprouting period when the dormancy ends, i.e., Sept. 20.
2. The sprouting of onion bulbs was completely inhibited even at the dose as low as 3000 r., and the storage period of treated bulbs was eventually prolonged so long as 4-5 months over ordinary storage period.
3. Inner buds of onion bulbs which were inhibited the sprouting by the irradiation were browned and dead, but the injured parts did not extend to the outside of the buds. In the bulbs which had been irradiated on September 20, the browned parts were somewhat larger than that of the bulbs treated soon after the harvest. It means that the elongation and/or differentiation of the inner buds might have occured during the period, so the irradiation in the
early stages (during the rest period) would be preferable for practical use.
4. The oxygen uptake in the disk part (bottom part) of the bulbs was not directly influenced by the gamma radiation, while, when the control bulbs had increased the respiratory activity after the presprouting period, the increase of respiration in the treated bulbs was remarkably suppressed.
5. Also the contents of sugar and ascorbic acid in the bulbs were not immediately affected by any dose of radiation used in this study. However, when the non-reducing sugar content in the untreated bulbs was gradually decreasing after the bulbs had commenced sprouting, the contents in the treated bulbs were not affected for any change.
6. The characteristic flavor of onion bulbs did not appneciably alter by the irradiation.
7. No significant differences of the concentra-tions of growth promoting and inhibiting substances in the inner buds were found to exist between the irradiated bulbs and the untreated ones.
