春化处理对'北农1号'萝卜碳水化合物含量及相关酶活性的影响

摘要

[目的]探讨春化处理对萝卜碳水化合物含量及蔗糖代谢相关酶活性的影响.[方法]低温处理萌动'北农1号'种子30 d,研究低温春化处理对萝卜叶片(源)及肉质根(库)碳水化合物含量的影响及糖代谢相关酶活性的变化规律.[结果]春化处理'北农1号'叶片及肉质根蔗糖、葡萄糖、果糖、棉子糖及总糖含量比对照降低,淀粉含量增加.叶片转化酶活性从"拉十字"开始到"拉十字"后21 d("破肚"前期)高于对照,"拉十字"后28 d("破肚"结束)转化酶活性降低且低于对照,蔗糖合酶与蔗糖磷酸合成酶活性在整个观察期都低于对照;春化处理促进了肉质根中性转化酶及蔗糖磷酸合成酶活性升高,酸性转化酶与蔗糖合酶活性变化不明显.[结论]低温春化处理影响了萝卜叶片及肉质根蔗糖代谢相关酶活性,碳水化合物代谢分配发生变化,叶片及肉质根中可溶性糖含量减少,抑制了肉质根的膨大.%[Objective] The aim of this paper was to investigate the effect of vernalization on carbohydrate content and sucrose metabolizing enzyme activities of radish (Raphanus sativus L.). [ Method ] Radish variety 'Beinong No. 1' was vernalized (treatment at 4℃ for 30 days) after germination. Mature leaves (source) and taproot (sink) were sampled to investigate carbohydrate content and sucrose metabolizing enzyme activities. [Result] After vernalization, soluble sugar content in leaves and fleshy taproot both decreased, starch content increased. The activity of NI (neutral invertase) in leaves of vernalized radish increased from two-leaf stage to the 21 st day after two-leaf stage, 28th day later, NI activity decreased and lower than that of control. The activities of SS (sucrose synthase) and SPS (sucrose phosphate synthase) were always lower than that of control during the tested period. The activity of NI and SPS in vernalized taproot decreased, whereas, neither the activity of AI (acid invertase) nor SPS had significant differences compared with that of control. [Conclusion] After vernalization, the carbohydrate metabolism changes and all soluble sugar content were declined in both leaves and taproot of 'Beinong No. l', vernalization influenced the activity of invertase, SS and SPS which of great importance in sucrose synthesis and degradation transport from source to skin in leaves and root. The reduced concentration of soluble sugar may be contributed to the restricted growth of the flesh taproot after vernalization.