高温诱导叶用莴苣抽薹过程中碳氮的变化分析

Study on Changes of Carbon and Nitrogen of Bolting in Lettuce Caused by High Temperature

为了明确叶用莴苣高温抽薹的生理学基础,以叶用莴苣易抽薹品种G-B30、G-B31和耐抽薹品种G-B4、G-B20为试材,研究叶用莴苣高温抽薹过程中各糖组分、可溶性总糖、淀粉、可溶性蛋白含量以及碳氮比的动态变化。结果表明,经高温处理后,除G-B20外,其他3个品种的葡萄糖、蔗糖和果糖含量均表现为抽薹临界期低于未抽薹时期。2个易抽薹品种均在抽薹临界期可溶性总糖含量达到最低,2个耐抽薹品种在花芽分化始期可溶性总糖含量最低。淀粉含量在花芽分化始期达到最大值,抽薹时期含量又迅速下降。2个易抽薹品种抽薹后期的半乳糖、可溶性蛋白质含量显著高于抽薹前,并有大量积累的趋势,而2个耐抽薹品种相反。2个易抽薹品种的C/N在抽薹期最低,2个耐抽薹品种在高温处理过程中C/N不断升高。综上,高温诱导叶用莴苣抽薹过程中可溶性蛋白、半乳糖、淀粉大量积累,而可溶性糖、葡萄糖、果糖、蔗糖含量及C/N降低。本研究结果为进一步探究叶用莴苣高温抽薹的分子机理提供了参考依据。

Two early-bolting cultivars G-B30, G-B31 and late-bolting cuhivars G-B4, G-B20 were used to study the dynamic changes of the sugar components, total soluble sugars, starch, soluble protein content and the ratio of carbon and nitrogen to clarify the physiological basis during lettuce bolting at high temperature. The results showed that under higher temperature treatment, apart from G-B20,the content of sucrose, fructose and glucose in 3 kinds of lettuce at bolting critical point were lower than unbolting stage. The content of total soluble sugar in two early-bolting cuhivars were the lowest at the bolting critical point, while the content of total soluble sugar in two late-bohing cultivars were lowest at the beginning stage of flower bud differentiation. The content of starch at flower bud differentiation stage reached a maximum, ~hile decreased rapidly during bolting. The content of galactose and soluble protein in early-bolting cuhivars were significantly higher than unbolting stage, there was a trend of accumulation, while they were opposite for late-bolting eultivars. At the bolting stage, C/N ratio reached a maximum in two easy bolting species, the ratio continued to rising in two later bolting varieties during high temperature processing. As a summary, soluble protein, galactose content accumulated, soluble sugar, glucose, fructose, sucrose, starch content and C/N declined during bolting. The above finding provides a reference basis for further study on molecular mechanism during lettuce bolting at high temperature.