Abstract: X-ray chronic irradiation was added to the adventitious bud by the tissue culture of oriental lily. Effects of different doses of radiation on the adventitious bud were observed and POD isozyme patterns of the adventitious bud were analyzed. X-ray obviously inhibites the growth of the adventitious bud while shows little effect on its multiplication. With the increase of the dose of radiation, the death rate rises. X-ray chronic irradiation leads to the change of POD isozyme patterns’ number and enhances the activity of these isozymes.