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.

Cenchrus spinifex  /  Rainfall  /  Shading  /  Plant type characteristics  /  Biomass