呼伦贝尔草甸草原杂类草碳水化合物含量的动态变化

Dynamics in carbohydrate content of forbs inHulunbeier meadow steppe

摘要:

碳水化合物是植物形态建成、返青、再生和抵御不良环境的重要能量物质,了解草原植物碳水化合物含量的季节动态变化是草原合理利用的基础。以呼伦贝尔草甸草原常见的8种杂类草:二裂委陵菜(Potentilla bifurca)、菊叶委陵菜(P.tanacetifolia)、地榆(Sanguisorba officinalis)、麻花头(Serratula centauroides)、细叶白头翁(Pulsatilla turczaninovii)、日荫菅(Carex pediformis)、山葱(Allium senescens)和狭叶柴胡(Bupleurum scorzonerifolium)为研究对象,探究植物地上部、茎基部、根部可溶性糖和还原糖含量的季节及年际动态变化。结果表明:2016年4~9月,供试植物地上部可溶性糖和还原糖含量总体呈先增加后降低的变化趋势,7月底达最大值;茎基部和根部可溶性糖含量在4~5月明显下降,表现为“下降-上升-再下降”的趋势。2015年8月,二裂委陵菜、地榆、麻花头、细叶白头翁、日荫菅和狭叶柴胡根部可溶性糖含量开始缓慢上升。干旱年份(2016年)严重抑制供试植物根部可溶性糖的积累。因此,建议呼伦贝尔草甸草原适宜放牧期为6~8月,干旱年份应减小放牧强度或提前休牧以保证草地可持续利用。

Abstract:

Carbohydrates are important energy substances for plant morphogenesis,regreen,regrowth and resistance to environment stress.It is the basis of grassland rational utilization to understand seasonal dynamics in carbohydrate content in grassland plants.In this study,the seasonal dynamics and interannual variations of soluble sugar and reducing sugar in shoot,stem base and root of 8 forbs (Potentilla bifurca,P.tanacetifolia,Sanguisorba officinalis,Serratula centauroides,Pulsatilla turczaninovii,Carex pediformis,Allium senescens,Bupleurum scorzonerifolium) in meadow steppe in Hulunbeier were studied.The results showed that the content of soluble sugar and reducing sugar in shoot of tested plants increased and thereafter decreased from April to September in 2016,and reached the maximum at the end of July.The content of soluble sugar in stem base and root decreased obviously from April to May,which showed a trend of ‘declining-rising-declining’.However,at the end of August 2015,the soluble sugar content in root of Potentilla bifurca,Sanguisorba officinalis,Serratula centauroides,Pulsatilla turczaninovii,Carex pediformis and Bupleurum scorzonerifolium began to rise slowly.The accumulation of soluble sugar in root of tested plants was seriously inhibited in drought year (2016).Therefore,it suggested that the suitable grazing period was June to the end of August,and the grazing intensity should be reduced or grazing rest in advance in drought years to ensure the sustainable utilization of grassland.