萝卜花芽分化过程中茎尖和叶片碳水化合物含量的变化

 以萝卜冬性品种‘一点红’和春性品种‘短叶13’为材料，研究花芽分化过程中茎尖和叶片以及萌动种子碳水化合物含量的变化。萌动种子在5℃下处理20 d，然后在温暖(>15℃)、长日照(16h)下生长，于不同花芽分化时期测定可溶性总糖、蔗糖和淀粉含量。结果表明：在花芽分化期间，无论是茎尖或是叶片，可溶性总糖、蔗糖和淀粉含量的变化趋势在两个品种之间较为接近。随着花芽分化的继续，可溶性总糖含量呈先上升后下降的趋势；蔗糖和淀粉含量则一直呈现上升趋势，在花芽分化完成后再下降。叶片中可溶性总糖、蔗糖和淀粉含量始终低于茎尖。冬性品种的蔗糖和淀粉含量在整个花芽分化期间始终较低，但在花芽分化初期的可溶性总糖含量则高于春性品种。

Changes in Carbohydrate Content of Stem Apices and Leaves during Floral Bud Differentiation in Radish (Raphanus sativus L.)

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．