1978 Volume 13 Issue 1-2 Pages 1-9
The gamma-ray dose and dose-rate effects and the loss of weight in the sprout inhibition of potato tubers were studied. The potato tubers used for this experiments were “Danshaku” variety which were yielded in October in Hokkaido.
The irradiation was carried out in the dose-rate range from 5 × 102 R/h to 5 × 105 R/h changing the dose from 3 kR to 15 KR in December of 1975 and 1976. 60Co-source used for those irradiation were 7300 Ci and 13000 Ci of a rod type one (1.4 cm ∅ × 30 cm), respectively. The irradiated potato tubers were stored for 5 to 7 months in dark natural condition, and their sprouting and their weight variation were observed.
The obtained results are summarized as follows:
1) The time of sprouting of the irradiated potato tubers is delayed compared to that of non-irradiated ones (control). The more the dose and the higher the dose-rate, the delayed time becomes larger. The potatoe tubers irradiated to 6 kR under 5 × 104 R/h are late about 60 days in sprouting from non-irradiated ones (Fig. 1)
.2) The sprout inhibition is more effective not only by heavier irradiation dose, but also by irradiation under higher exposurerate (Fig. 2 and Fig. 3).
3) The necessary and sufficient dose for the sprout inhibition is estimated to be about 10.5 kR for exposure-rate of 5 × 103 R/h, and it increases rapidly for the lower exposure-rate, while it decreases with the rate of about 2 kR per one order of magnitude of exposure-rate for the higher exposure-rate (Fig. 4).
4) The rate of weight loss of irradiated potato tubers is small compared to that of non-irradiated ones, and ones more irradiatedshow less rate of weight loss (Fig. 5 and Fig. 6). The exposure-rate dependence in weight loss is not apparent (Fig. 7).
