Abstract: Under the context of global change， plant invasion events have become more frequent and widespread. Rainfall and light are important ecological factors that affect the adaptation and dispersal of invasive plants. Cenchrus spinifex， a major invasive plant in the Horqin Sandy Land China， has expanded its invasion area in recent years， posing significant threats to local biodiversity and ecosystem functions. Understanding its invasion and adaptation mechanisms is crucial for devising effective control strategies. In this study， we established an in situ field experiment by using pipe cultivation to explore the functional traits of Cenchrus spinifex under three treatments： increased rainfall， reduced rainfall， shading， and a control （CK） group. The results revealed that both increased rainfall and reduced rainfall significantly enhanced plant heigh. increased rainfall increased branching， the number of reproductive branches， spiny burs， leaf biomass， and leaf contribution ratio significantly. Reduced rainfall promoted tiller number， total root length， root contribution ratio， and spiny bur contribution ratio significantly. In contrast， shading significantly reduced crown width， spiny bur number， total root length， and biomass of all organs. These findings indicate that Cenchrus spinifex adapts to variations in rainfall and light availability by modulating plant architecture， biomass of organ and biomass allocation. This study provides a theoretical basis for revealing the invasion and adaptation mechanisms of Cenchrus spinifex under the background of climate change， and to provide reference for predicting its suitable or spreading areas.

Key words: Cenchrus spinifex, Rainfall, Shading, Plant type characteristics, Biomass

摘要： 全球变化背景下，植物入侵事件频发，入侵范围扩大。降雨和光照是影响入侵植物适应和扩散的重要生态因子。少花蒺藜草（Cenchrus spinifex）是科尔沁沙地主要入侵植物，近年来其入侵面积逐步扩大，严重威胁着当地生物多样性和生态系统功能，对其入侵和适应机制的探索是制订防控机制的重要依据。本试验通过管培方式建立少花蒺藜草野外原位研究样地，设置增雨，减雨和遮光3种处理，并增设对照试验，以探索植物功能性状的变化规律。结果表明：增雨和减雨均提高了少花蒺藜草株高，此外，增雨显著增加少花蒺藜草分枝数、繁殖枝数量、刺苞数并提高叶生物量和叶贡献率，减雨显著增加少花蒺藜草分蘖数并提高了总根长、根贡献率和刺苞贡献率；遮光显著降低少花蒺藜草冠幅、刺苞数、总根长和各器官生物量。研究表明少花蒺藜草能够通过调整株型特征、生物量及其分配等一系列途径适应降雨量和光照的变化。本研究为揭示少花蒺藜草在气候变化背景下的入侵和适应机制提供了理论依据，同时可为预测其适生或扩散区域提供参考。

关键词: 少花蒺藜草, 降雨量, 遮光, 株型特征, 生物量