This paper describes the basic principle and experimental method for irradiating living plants by analysing the effect of
60
Co γ-ray radiation dose on wheat and rice plants. With the measurement of the percentage of C
H
O and N in plants at the different growing period
the absorbed coeffecient of quality-energy and the F value of the transforming factor between Roentgen and Grey (X-D) were obtained. The F value for rice was 9.649× 10
-3
—9.452×10
-3
Gy from tillering period to grain filling stage and that for wheat was 9.633×10
-3
—9.551×10
-3
Gy. In addition the radiation absorbed dose for rice and wheat plants could be calculated. The results of the experiment provided the basic data for radiation of rice and wheat plants at the growing period to enchance the radiation mutagenic frequency.