Effects of ¹³⁷Cs γ Radiation on Bulbs of Different Tulipa gesneriana Cultivars

In March 2018, bulbs of Tulipa gesneriana ‘Red label’, T. gesneriana ‘Jan vannes’ and T. gesneriana ‘Royal virgin’ were harvested fromTaizhou, Zhejiang province, and stored with controlled temperature and humidity. On June 5th, they were irradiated by different dose of 137Cs γ rays.On December 1st, treated bulbs were planted in greenhouse and determinations were made on their flower bud differentiation, emergence rate,seedling stage and flowering traits. The results showed that with the increase of radiation dose, the growth of bulb’s central buds inhibited, the flowerbud differentiation progress slowed, the flower structure uncompleted, and the emergence rate lowered. The main variations in the bud stagedemonstrated short plants, slow growth, leaf dehiscence or deformed leaves. Flowering stage demonstrated the edges of the petals cracks of cultivartreated by 5 Gy compared with that of the control. The scape of cultivar treated with 10 Gy could not grow out, the pistil and stamen were deformed,and some petals were abnormal or missing.