呼伦贝尔草甸草原3种禾草碳水化合物季节动态研究

贮藏碳水化合物对牧草生命代谢、再生、返青及逆境的适应性等方面有重要作用。本研究于2015年7月—2016年9月，分析了呼伦贝尔草甸草原中羊草（Leymus chinensis）、无芒雀麦（Bromus inermis）和糙隐子草（Cleistogenes squarrosa）3种植物碳水化合物含量的季节变化规律，探讨牧草生长对气候环境的适应性特点，以期为草地合理利用提供指导。研究结果表明：3种禾草碳水化合物含量随季节变化显著（P<0.05），可溶性糖含量均在8月最高，羊草与无芒雀麦的还原糖和淀粉含量在6月最高，糙隐子草则在7月最高；糙隐子草的可溶性糖与淀粉含量显著小于羊草和无芒雀麦（P<0.05），并主要分配在地上部分，羊草茎基部与根部的各碳水化合物含量显著小于无芒雀麦（P<0.05）；碳水化合物含量年际间差异较大，干旱年份草地植物根部碳水化合物贮藏水平偏低，该区域草地宜降低载畜率或提前休牧。

Seasonal Carbohydrate Changes of Three Grasses in Hulunbuir Meadow Steppe

Carbohydrate reserves in the forages play an important role in the metabolism,regrowth,regreening,and stress tolerance. Seasonal variations of carbohydrates content in the species of Leymus chinensis,Bromus inermis,and Cleistogenes squarrosa were studied in Hulunbuir meadow steppe from July 2015 to September 2016. The objective was to understand the critical factors of influencing the changes of carbohydrate content and guide the grassland management. The results showed that the significant seasonal changes of carbohydrates content were observed in the three grasses (P<0.05). Soluble sugar content was the highest in August for all species. The soluble sugar and starch contents in L. chinensis and B. inermis were the highest in June compared to those in C. squarrosa in July. The soluble sugar and starch contents in C. squarrosa were significantly lower than those in L. chinensis and B. inermis (P<0.05),and were mainly distributed in the aboveground. The carbohydrates content in the stem bases and roots of L. chinensis were significantly lower than those in B. inermis (P<0.05). Interannual variation of carbohydrate content was significant difference. The carbohydrate reserves in root were low during the drought year. Therefore,decreasing stocking rate and ending grazing earlier should be an adaptive way for the grassland management in the drought year.