内蒙古典型草原羊草和大针茅地下器官中碳水化合物含量的季节性变化

多年生牧草在地下器官中贮藏的碳水化合物是春季萌发生长和刈牧后再生的物质基础。羊草和大针茅是内蒙古典型草原地带性分布的优势种。为了研究草原植物碳水化合物贮藏特性,采用高效液相色谱技术对羊草和大针茅的贮藏性碳水化合物的种类组成及季节变化进行了测定。结果表明,羊草和大针茅地下器官的贮藏性碳水化合物的组分主要包括果聚糖、蔗糖、葡萄糖、果糖、甘露醇和淀粉。其中甘露醇、淀粉和果聚糖在2种牧草地下器官中的含量均居前3位。羊草地下器官碳水化合物的含量显著高于大针茅,其果聚糖和淀粉含量分别是大针茅的3.2和3.6倍。5月20日-10月15日,羊草和大针茅地下器官中的碳水化合物总量、可溶性碳水化合物含量、淀粉含量、甘露醇含量和果聚糖含量均表现出“降低-升高-再降低-再升高”的特征。不同碳水化合物组分冬前积累和春季降解的起止时间也存在较大差异。

Changes of carbohydrate contents in below ground organs of Leymus chinensis and Stipa grandis in the inner Mongolian steppes

Perennial grasses store enough carbohydrates in below ground organs for germination in spring or for regrowth after cutting.Leymus chinensis and Stipa grandis are dominant species with a wide distribution in the Inner Mongolian steppes.To understand the characteristics of carbohydrate storage of perennial grasses,we analyzed the content and seasonal dynamics of carbohydrate components in below ground organs of L.chinensis and S.grandis using high performance liquid chromatography.The results showed that the carbohydrate components in below ground organs of both L.chinensis and S.grandis included fructan,sucrose,glucose,fructose,mannitol and starch.The major components of below ground organs of both grasses were fructan,mannitol and starch and L.chinensis had much higher levels than S.grandis.The fructan and starch contents of L.chinensis were 3.2 and 3.6 times respectively those of S.grandis.The seasonal changes of total carbohydrate,soluble carbohydrate,starch,mannitol and fructan in the below ground organs of both species showed the same 'down-up-down-up' trend.Different carbohydrate components had different starting and ending times for accumulation before winter and for cleavage after spring.