中文摘要：

褐鳞苔草（Carex brunnescens）是黄河源区（玛曲）沙漠化草地具有较强固沙能力的先锋植物,对维护玛曲高寒草地生态系统稳定性有重要作用。为了揭示褐鳞苔草固沙的生物学特征,该研究在野外观测了其物候学特征,地上和地下器官生长进程以及地下器官形态学特征。结果表明,褐鳞苔草返青早,生育期较长,具有二次开花和结果的生长特性。褐鳞苔草单株叶宽、单株叶长、单株叶片数量、群落密度、群落盖度和群落叶片密度从展叶期-果实成熟期-黄枯期呈显著增加而后趋于稳定;而单株叶丛高度、单株叶面积和群落叶片面积呈显著增加而后减小的趋势。褐鳞苔草地下茎（水平茎和垂直茎）和根系适宜生存的沙层深度为0~60 cm。不同沙层深度（0~20,20~40和40~60 cm）均以直径为0.2~0.5 mm的中根数量最多,在20~40 cm沙层内细根（〈0.2 mm）、中根（0.2~0.5 mm）和粗根（〉0.5 mm）的根系总长度均最大,0~20 cm沙层最小。在10-30 cm沙层内,水平茎、垂直茎和主根长度、鲜重和干重均最大,40~50 cm沙层内最小。以上结果表明,褐鳞苔草能很好地适应高寒风沙生境,可作为玛曲高寒沙漠化草地生态恢复的建群种,具有良好的推广应用前景。

英文摘要：

Carex brunnescens, a pioneer plant that has an excellent ability to fix sand in the source region of the Yellow River （Maqu）, plays an important role in maintaining the ecosystem stability of alpine grassland in Maqu. In this study, the biological characteristics （phonological characters, the growth process of overground and underground organs, and the morphological characters of underground organs） of C. brunnescens were studied by a field observation experiment. The results showed that C. brunnescens had the characteristics of turning green earlier than other plants, a long growth period, and two flowering and fruiting cycles. The leaf width, length and number of a single plant, and the density, coverage and leaf density of community increased significantly from the leaf extension period to the fruit mature period and then tended to be stable in the withering period, while the plant height and leaf area of a single plant and the leaf area of community rose significantly at first and then decreased. Underground stems （horizontal and vertical stems） and roots of C. brunnescens could survive in sand at a depth of 0-60 cm. The number of middle roots （0.2-0.5 mm in diameter） was the largest in all soil layers （0-20, 20-40 and 40-60 cm）, and the total length of fine roots （〈0.2 mm） were the maximum in the sand at a depth of 20-40 cm, while the total length of middle roots was the maximum in the sand layer at a depth of 0-20 cm. The length, fresh weight and dry weight of the main root, horizontal and vertical stems was the maximum in the sand layer at a depth of 10-30 cm and was the minimum in the sand layer at a depth of 40-50 cm. It is concluded that C. brunnescens can well adapt to the alpine sand habitat of Maqu, can be used as the constructive species for ecological restoration in the alpine desertified grassland of Maqu, and has good popularization and application prospects.