Abstract: Shading is a crucial environmental factor that influences plant seed germination and seedling establishment. This study aimed to investigate the impact of shading on Stellera chamaejasme seedling settlement in alpine grassland. Artificial control experiments were carried out in natural habitat to explore the emergence and seedling settlement performance of S. chamaejasme seeds under different shading heights (10 cm,15 cm and 20 cm) and orientations (east,west,south and north).The results revealed that various shading treatments significantly reduced surface soil temperature(P<0.05) and increased soil water content in alpine grassland(P<0.05). Different shading treatments reduced in varying degrees of reduction in the germination rate and seedling establishment rate of S. chamaejasme seeds. Compared to the control group,shading treatments in the east,south and north did not significantly affect the germination rate of S. chamaejasme seeds,whereas shading treatment in the west significantly reduced the germination rate of S. chamaejasme seeds (P<0.05). The seedling establishment rate of S. chamaejasme did not significantly differ among various shading treatments,with all treatments achieving 100% establishment.The analysis showed that shading was an important environmental factor affecting the settlement of S. chamaejasme seedlings. Therefore,maintaining the alpine grassland plant community at a certain height level can effectively curb the settlement and population dispersal of S. chamaejasme seedlings.

Key words: Alpine grassland, Shade, Stellera chamaejasme, Seedling settlement

摘要： 遮荫是影响植物种子萌发和幼苗定居的重要环境因素。为了探明遮荫对高寒草地狼毒（Stellera chamaejasme）种苗定居的影响，本研究在其原生境下开展人工控制试验，探究了狼毒种子在不同遮荫高度（10 cm，15 cm，20 cm）和不同遮荫方位（东向、西向、南向、北向）下的出苗和幼苗定居表现。结果表明：不同遮荫处理均显著降低了高寒草地土壤表层温度（P<0.05），增加了土壤含水量（P<0.05）；不同高度遮荫处理均能不同程度地降低狼毒种子出苗率和成苗率。与对照相比，东向、南向和北向遮荫处理对狼毒种子出苗率均无显著影响，而西向遮荫处理能显著降低狼毒出苗率（P<0.05）；狼毒的成苗率在各方位遮荫处理下无显著性差异，均为100%。本研究表明，遮荫是影响狼毒种苗定居的重要环境因子。因此，维持高寒草地植物群落在一定的高度水平，可有效遏制狼毒种苗定居和种群扩散。

关键词: 高寒草地, 遮荫, 狼毒, 种苗定居