萝卜肉质根膨大过程中糖含量及蔗糖代谢相关酶活性分析

用根冠比差异显著的萝卜品系为材料，研究了肉质根膨大过程中的若干生理生化变化。结果表明：4个品系肉质根的库活性变化情况基本一致，“破肚”后一周内达到最大；可溶性总糖、果糖和蔗糖含量初期下降，“破肚”期降至最低值，其中低根冠比品系“NAU-LR-04”蔗糖含量一直高于其它高根冠比品系，而其果糖含量则相对较低。肉质根中蔗糖合酶的活性变化与肉质根库活性的变化趋势基本一致，且低根冠比品系蔗糖合酶活性相对高于高根冠比品系，推测蔗糖合酶可能是调节肉质根蔗糖水平、控制肉质根库活性的关键酶。

Changes of Sugar Content and Sucrose Metabolizing Enzyme Activities During Fleshy Taproot Development in Radish (Raphanus sativus L.)

Several physiological changes during the development of radish fleshy taproot were studied u- sing the advanced inbred lines of different ratio of root to shoot(R/S).The results showed that sink activity patterns of taproot were much similar among the four lines. The contents of carbohydrates including soluble to- tal sugar, sucrose and fructose decreased at the beginning of taproot enlarging, and to the minimum at the stage of the primary cortex split. The sucrose content of the low R/S line NAU-LR-04 was higher than those of three high R/S lines at all stages, while the fructose content was lower in NAU-LR-04. Changes of activities of sucrose synthase(SuSy)were similar to sink activities in all lines, and the activity of SuSy in low R/S line was higher than those of high R/S lines. It can be inferred that the SuSy may play an important role in the su- crose level regulation and sink activity control during radish fleshy taproot thickening.