[en] A large number of young lettuces were irradiated by carbon ion and neon ion for searching the effects of heavy ion doses. The irradiated young lettuces were grown up normally on the dose of <30 Gy. The growing up rate of the lettuce decreased rapidly on the dose of >100 Gy. Sprouting tests of lettuce seed were carried out by irradiation dose of <30 Gy for research of hormesis effect. The sprouting rate of irradiated lettuce seeds at temperature 30 degC increased at dose of 0.3 Gy for carbon ion, and at dose of 0.1 Gy for neon ion, in comparison with the one of non-treated seeds. The sprouting test at 35 degC were carried out, also. An initial sprouting promotion effect, the hormesis effect was suggested at low dose of the heavy ions. Possibility of technical application aiming at hormesis effects for creating mutant should be investigated on heavy ion beam irradiation also, as well as the gamma-ray irradiation. (M. Suetake)