Résumé
Radiosensitivity of germinating seeds and seedlings increased by increasing the dose and was found to be affected by soaking in water. Meanwhile, GA gave promising results as protectant and reparator of germinating seeds from irradiation injury. These results suggest the occurrence of some changes in the hormonal picture of the seeds due to these treatments. When the air-dry seeds were extracted and the natural growth substances were separated and identified the ether fraction was found containing a growth inhibitor [presumably ABA] and a growth promoter identified as IAN. The following changes were detected due to different treatments: [a] soaking in distilled water resulted in formation of a non-indolic growth promoter, a decrease in the amount of the growth inhibitor and an increase in the amount of IAN. [b] Irradiation of air-dry seeds with 10 kr dose increased the amount of IAN as well as the amount of the growth inhibitor. The effect of irradiation in stimulating the formation of the growth inhibitor was greatly lessened when the seeds were soaked in water before irradiation, [c] Soaking the seeds in GA solution [40 ppm] increased the amount of the growth promoters, but GA was less effective than distilled water in decreasing the amount of the growth inhibitor