Abstract: Winter cultivar ‘Yidianhong’ and spring cuhivar ‘Duanye 13’were used to study the carbohydrate content of stem apices and leaves during the progress of floral bud differentiation． Germinated radish seeds were subjected to chilling at 5℃ for 20 days．After low temperature treatment．all seedlings were transplanted into glasshouse under warm (>15℃)and long photoperiod (16 h)growth condition. Amounts of total soluble sugars，sucrose and starch were assayed during the various floral bud differentiation stages．The following conclusions were drawn：(i)111e amounts of total soluble sugars．sucrose and starch during the floral bud differentiation，either in stem apices or in leaves。showed a similar tendency between the spring cuhivar and the winter cuhivar．(ii)111e total soluble sugar content increased during the initial stages of floral bud differentiation and then decreased，while the sucrose and starch content increased steadily until floral bud differentiation was completed． (iii)The mounts of total soluble sugars．sucrose and starch in leaves were less than that in stem apices．(iV)Total soluble sugar content in the winter cuhivar was much higher than that in the spring cuhivar during the initial stage of floral bud differentiation，but the sucrose and starch content in the winter cuhivar were lower than that in the spring cultivar during the entire floral bud differentiation．

Key words: Raphanus sativus L．, Floral bud differentiation, Total soluble sugar, Sucrose, Starch