PRF/J: The Role of Limiting Resources in Controlling Mutualistic and Parasitic Effects of Mycorrhizae

9403308 Johnson这项研究将确定哪些因素调节菌根与寄主植物的共生或寄生关系。有待验证的假设是，有限土壤资源的富集导致菌根植物分配给根分泌物的碳较少，从而使寄生形式的水泡-丛枝菌根（VAM）真菌具有选择优势。野外工作将在两个NSF长期生态研究（LTER）地点（明尼苏达州的Cedar Creek自然历史区和新墨西哥州的Sevilleta）的24块施肥、灌溉和对照地块上进行。VAM真菌在农业系统中的研究相对较好，但在自然生态群落和生态系统中却知之甚少，尽管它们在土壤中无处不在。然而，即使在有管理的农业环境中，与我们对农业生态系统其他组成部分的了解相比，这些真菌仍在很大程度上被视为“黑箱”。对VAM生物学和生态学的更彻底的了解可能会导致牧场主和农民在菌根接种计划方面的改进，而对天然菌根生物多样性的更全面的认识无疑会导致管理农业和森林系统的不可预见的改进。＊＊＊

9403308 Johnson This research will ascertain what factors regulate mycorrhizal effectivity in relation to mutualistic or parasitic relationships with their host plants. To be tested is the hypothesis that enrichment of a limiting soil resource causes mycorrhizal plants to allocate less carbon to root exudates, giving a selective advantage to parasitic forms of vesicular - arbuscular mycorrhizal (VAM) fungi. Fieldwork will be conducted on 24 fertilized, irrigated, and control plots at two NSF Long Term Ecological Research (LTER) sites (Minnesota's Cedar Creek Natural History Area and Sevilleta in New Mexico). %%% VAM fungi, relatively better studied in agricultural systems, are poorly known in natural ecological communities and ecosystems despite their ubiquitousness in soils. Nevertheless even in managed agricultural settings, these fungi are still largely regarded as "black boxes" in comparison to our knowledge of other components of agroecosystems. A more thorough understanding of VAM biology and ecology is likely to lead to improved practices by ranchers and farmers with regard to successful mycorrhizal inoculation programs, while a more comprehensive appreciation of natural mycorrhizal biodiversity will undoubtedly lead to as yet unforeseen improvements in managed agricultural and forest systems. ***