关键词: 紫花苜蓿, 根系, 非结构性碳水化合物, 季节性变化, 聚类分析

Abstract: This paper studied the seasonal variation in contents of non-structural carbohydrate in roots of different alfalfa varieties during late autumn (October 15) and early spring (April 8), so as to provide theoretical basis for extension and application of local alfalfa varieties. Twelve alfalfa varieties at home and abroad were taken as experimental materials, the cold resistant physiological characteristics of different alfalfa varieties were compared and studied, through testing the contents of soluble sugar, reducing sugar, total sugar and starch in the roots of these 12 alfalfa varieties during late autumn and early spring. The results showed that there were significant differences (P<0.05) in contents of soluble sugar, reducing sugar, total sugar and soluble sugar/starch value in roots of different alfalfa varietied in late autumn and early spring. And there were significant differences (P<0.05) in contents of starch during autumn, but no obvious difference (P>0.05）was found in spring. There was a large difference in the descent range of non-structural carbohydrate content in roots of different alfalfa varieties from late autumn to early spring next year. And the decline rate in contents of soluble sugar, starch, reducing sugar and total sugar was 8.71%~41.43%, 51.21%~79.37%, 17.47%~56.16% and 26.10%~48.78%, respectively. These 12 alfalfa varieties were classified into 3 groups by clustering analysis. The group I had lower starch content in root, including M1 and M8 varieties, their starch contents were lower than 3.0%. The group Ⅱ had higher starch content in root, including 5 varieties: M3, M4, M6, M7 and M11 and their starch contents were 3.91%~4.82%. And group Ⅲ had higher soluble sugar content in root including 5 varieties: M2、M5、M9、M10、M12 and their soluble sugar contents were over 8.0% and the starch contents were between 3.0%~4.0%.

Key words: alfalfa, root system, non-structure carbohydrates, seasonal variation, clustering analysis