生物种间相互作用对植物适应环境的影响一直受到关注。研究已表明种间负相互作用（如竞争、捕食和寄生）对植物适应环境有重要影响，而植物之间的互惠以及共生对植物适应胁迫环境的影响机理有待揭示。本项目拟研究"植物-丛枝菌根共生是否和如何通过影响宿主植物的适合度从而影响植物对低磷土壤的适应"。项目以模式植物蒺藜苜蓿（Medicago truncatula L.）与丛枝菌根真菌共生为研究体系，研究：（1）低磷土壤下丛枝菌根对根系形态表型变异及植物生长和繁殖适合度的影响；（2）通过同质园实验和交互种植实验，研究低磷土壤下根系形态和丛枝菌根的变化是否具有跨世代传递性、植物对低磷土壤的适应性反应；（3）通过同位素示踪实验，研究丛枝菌根在宿主植物适应低磷土壤的作用机理。结果将揭示丛枝菌根对植物适应低磷土壤的影响及机理，有助于加深认识植物适应胁迫环境的策略及生物种间相互作用在植物适应胁迫环境中的作用。

Adaptation to local habitat is of important for plants to suivial and develop population in the environment. Except abiotic factors, biotic interactions (e.g. competition, predation, parasitism and mutualism) also contribute to plant adaptation to environment. Although experiments have showed that negative intraction between plant and other species (e.g. plant competition, herbivory and parasitism) play important role in plant adaptation to local environment, whether and how mutualism between species play a role in plant adaptation is poorly understood. The overall goal of this grant project is to examine whether and how symbiosis between plant and arbuscular mycorrhizal fungi (AMF) affect host plant adaptation to low soil phosphors (P) .The central hypotheses of this project are that AMF may reduce root mophorlogical phenotypic plasticity and maitain fitness of host plant under low P soil through enhancing functions of root system. Specific objectives of this project are: (1) to examine whether and how AMF affect host plant root mophorlogical phenotypic plasticity and fittness of growth and reproduction in host plant; (2) to test whether transgenerational plasticity and plant adaptation occur under low P soil and lack of AMF; (3) to characterize what are machnisms that AMF affect plant adaptation to low P soil. Model plant Medicago truncatula L. symbiosis with AMF are used as model symbiotic system in this study. Common garden experiment and reciprocal transplant experiment are conducted to test whether transgenerational plasticity and plant adaptation occur under low P soil and lack of AMF. Isotope tracing (13C, 15N and 32 P) is employed to test how AMF mediate nutrient uptake and allocation. Our project will reveal, for the first time, that how AMF affect host plants in adaptation to low P soil. The significance of this project is to enhance our understanding what strategy the plants may take under stress environment, and that the mutual symbioses between species can play important roles in plant adaptation to stress envrioment.