萝卜种质资源肉质根可溶性糖组分质量分数特征及与肉色的关系

Natural Variation of Soluble Sugar Mass Fraction and Its Relationship with Visual Flesh Color in Radish(Raphanus sativus L.)Taproots

连续3 a利用高效液相色谱法对包含129种白肉萝卜、48种绿肉萝卜和18种红肉萝卜等共计195种萝卜品种的肉质根进行了糖组分的鉴定和质量分数的测定,并对数据进行了聚类分析和相关性分析。在供试萝卜肉质根中共鉴定出果糖、葡萄糖和蔗糖3种类型的糖。其中,葡萄糖质量分数最多,其次是果糖和蔗糖,并且在超过20%(46/195)的萝卜品种中未检测到蔗糖。糖质量分数的变异幅度较大,总糖质量分数为5.39~47.08 mg/g,葡萄糖质量分数为3.2~27.61 mg/g,果糖质量分数为0.6~19.42 mg/g,蔗糖质量分数为0~9.02 mg/g。不同萝卜品种糖分构成存在较大差异,葡萄糖/果糖比值为1.01~6.67。通过聚类分析,这些萝卜品种被聚为4类,其中C4类可溶性总糖质量分数最高,均值达到41.81 mg/g;C1类可溶性总糖质量分数最低,均值仅为13.68 mg/g。相关性分析表明,糖质量分数与萝卜肉色密切相关,绿肉萝卜总糖质量分数最高,其次是红肉萝卜和白肉萝卜。综上,萝卜肉质根中主要糖组分为葡萄糖和果糖,糖质量分数与萝卜皮色不相关,而与肉色相关性较强。

Radish is an important root vegetable crop worldwide.Assessment of sugar composition in taproots of radishes will provide helpful information for quality breeding of radishes.In this study,195 cultivars including 129 white-fleshed,48 green-fleshed and 18 red-fleshed radishes were collected and the variation of sugar composition in taproots was evaluated using high performance liquid chromatography analysis in three successive years.Three sugars including glucose,fructose and sucrose were identified in radish taproots.The most abundant sugar was glucose,followed by fructose and sucrose,and more than 20%(46/195)of cultivars were sucrose free.These radish cultivars presented a wide range of variation from a minimum 5.39 mg/g to a maximum of 47.08 mg/g in total sugar mass fraction,from 3.2 mg/g to 27.61 mg/g in glucose mass fraction,from 0.6 mg/g to 19.42 mg/g in fructose mass fraction,from 0 to 9.02 mg/g in sucrose mass fraction,and from 1.01 to 6.67 in glucose/fructose ratio.By cluster analysis,all the tested cultivars were clustered into four groups.Cluster 4 had the highest mean for total sugar mass fraction of 41.81 mg/g,and Cluster 1 had the lowest mean for total sugar mass fractions of 13.68 mg/g.Furthermore,correlation analysis indicated that the sugar mass fraction was significantly correlated with the flesh color.Green-fleshed radishes had the highest amount of sugars,followed by red-fleshed and white-fleshed ones.Overall,glucose and fructose are the main sugars in these radish cultivars.The sugar mass fraction is not related to the skin color,but is strongly correlated with the flesh color of radishes.