Data from: Mycorrhizas influence functional traits of two tallgrass prairie species

Over the past decade, functional traits that influence plant performance and thus, population, community, and ecosystem biology have garnered increasing attention. Generally lacking, however, has been consideration of how ubiquitous arbuscular mycorrhizas influence plant allometric and stoichiometric functional traits. We assessed how plant dependence on and responsiveness to mycorrhizas influence plant functional traits of a warm-season, C4 grass, Andropogon gerardii Vitman, and the contrasting, cool-season, C3 grass, Elymus canadensis L. We grew both host species with and without inoculation with mycorrhizal fungi, across a broad gradient of soil phosphorus availabilities. Both host species were facultatively mycotrophic, able to grow without mycorrhizas at high soil phosphorus availability. A. gerardii was most dependent upon mycorrhizas and E. canadensis was weakly dependent, but highly responsive to mycorrhizas. The high dependence of A. gerardii on mycorrhizas resulted in higher tissue P and N concentrations of inoculated than noninoculated plants. When not inoculated, E. canadensis was able to take up both P and N in similar amounts to inoculated plants because of its weak dependence on mycorrhizas for nutrient uptake and its pronounced ability to change root-to-shoot ratios. Unlike other highly dependent species, A. gerardii had a high root-to-shoot ratio and was able to suppress colonization by mycorrhizal fungi at high soil fertilities. E. canadensis, however, was unable to suppress colonization and had a lower root-to shoot ratio than A. gerardii. The mycorrhiza-related functional traits of both host species likely influence their performance in nature: both species attained the maximum responsiveness from mycorrhizas at soil phosphorus availabilities similar to those of tallgrass prairies. Dependence upon mycorrhizas affects performance in the absence of mycorrhizas. Responsiveness to mycorrhizal fungi is also a function of the environment and can be influenced by both mycorrhizal fungus species and soil fertility.过去十年来，影响植物性能，进而波及种群、群落与生态系统生物学的功能性状，已受到学界越来越多的关注。然而，针对无处不在的丛枝菌根（arbuscular mycorrhizas）如何调控植物异速生长与化学计量学功能性状的相关研究，仍较为匮乏。本研究以暖季型C4草本大须芒草（Andropogon gerardii Vitman）与冷季型C3草本加拿大披碱草（Elymus canadensis L.）为研究对象，评估了植物对菌根的依赖性与响应性如何作用于其功能性状。我们在跨度宽泛的土壤磷有效性梯度下，分别对接种与不接种菌根真菌的两种宿主植物开展栽培实验。两种宿主植物均为兼性菌根营养型，在土壤磷有效性较高的条件下可脱离菌根独立生长。大须芒草对菌根的依赖性最强，而加拿大披碱草的依赖性较弱，但对菌根的响应性更高。大须芒草对菌根的高依赖性，使得接种植株的组织磷与氮浓度显著高于未接种植株。在未接种菌根的情况下，加拿大披碱草可获取与接种植株相当的磷与氮量，这源于其对菌根养分吸收的低依赖性，以及其显著调节根冠比的能力。与其他高依赖性菌根物种不同，大须芒草拥有较高的根冠比，且在土壤肥力较高时可抑制菌根真菌的定殖。而加拿大披碱草无法抑制菌根真菌定殖，且根冠比低于大须芒草。两种宿主的菌根相关功能性状，很可能会影响其在自然生境中的生长表现：二者在与高草草原土壤磷有效性相近的条件下，均可从菌根共生中获得最大的正向响应。对菌根的依赖性会影响无菌根环境下的植物生长性能；对菌根真菌的响应性同样受环境调控，且可被菌根真菌种类与土壤肥力共同影响。