根系形态可塑性是研究植物适应与进化的一个重要切入点。开展根部半寄生植物根系形态可塑性研究，有助于解析植物从自养向寄生的转变过程及其进化驱动力。然而，由于多数根部半寄生植物根系发育不健全，甚至严重退化，其根系养分吸收能力及形态可塑性向来被忽略。一些马先蒿属根部半寄生植物根系形态具有明显可塑性，是研究根部半寄生植物根系响应环境变化的理想材料。本研究拟选择具明显根系形态可塑性，但根系发育投资策略、寄主依赖程度和地理分布范围均不同的三种马先蒿为研究对象，结合野外样方调查和盆栽试验，解析三种马先蒿根系形态对氮磷供给、AM真菌来源和寄主种类变化的可塑性响应规律及其与养分吸收和植株生长的相关性，探讨三种马先蒿根系形态可塑性水平与环境适应能力的关系。该研究有助于解析根部半寄生植物根系形态对环境变化的响应规律及其生态学意义，并可望为揭示根部半寄生植物养分吸收方式的转变过程及环境驱动因子提供新的视角和线索。

Root morphological plasticity has been an important cut-in point for investigations of plant adaptation and evolution. A better knowledge of root morphological plasticity in root hemiparasitic plants and relevant driving forces can help unravelling responses in root systems during the transition from autotrophic plants into parasitic ones. Unfortunately, because most root hemiparasitic plants often have underdeveloped root systems or even virtually no roots in some extreme cases, root morphological plasticity in root hemiparasitic plants and their roles in nutrition acquisition have been overlooked. Recently, we have found that some root hemiparasitic Pedicularis species showed high plasticity in root morphology. These plants are ideal materials for the study of root morphological plasticity in root hemiparasitic plants. In this project, we will use three Pedicularis species that show high root morphological plasticity, but have different strategies in root development in responses to changing environment conditions, different host preference and dependency, and different distribution ranges. The study will encompass field excavation and pot cultivation to assess the level of plasticity and response norms of these species to variations of tested environmental factors. Based on our previous experiments, we will specifically focus on the effects of soil nitrogen and phosphorus levels, AM fungi, and host plant identity on root morphology of these three root hemiparasites. Correlation analysis will be conducted between root morphological changes and nutrient uptake efficiency of the hemiparasites under different conditions to better understand if root morphological plasticity plays a role in adaptation of these root hemiparasites. This project is the first to address the issue of root morphological plasticity in parasitic plants. Knowledge obtained will shed light on the changes of root morphology in root hemiparasitic plants in response to environmental changes and its ecological significance. In addition, it may provide new perspectives and clues for the study of transition from autotrophic to parasitic status in evolution of parasitism in plants and possible driving environmental factors.