Diversity and functional adaptation of mycorrhizal systems to extreme edaphic factors in British Columbia serpentine ecosystems

菌根是不同真菌与大多数植物根部之间的专属共生体，它们对地下森林生态系统中的养分和能量交换至关重要。在某种程度上，真菌促进了植物营养和水分的吸收，并减少了有毒金属的影响；作为交换，植物为真菌提供了光合碳(C)。这项建议测试了与极端土壤的物理、化学和生物特性有关的选择压力对蛇形景观中的菌根真菌的影响。在全球范围内，蛇形生态系统支持着截然不同的、往往是独特的植物群落；然而，我们对支持这些系统的土壤生物学过程，或者与根相关的真菌如何促进植物的生存和适应知之甚少。通过温室和实地研究，我将(1)评估既适应蛇形场地又适应非蛇形场地的针叶树(包括白皮松)的根真菌共生体和幼苗生长，白皮松是一种仅出现在高海拔地区且在不列颠哥伦比亚省(COSEWIC)处于“濒危”状态的物种，(2)评估林下真菌异养植物的菌根结构、真菌特性和作用，这些植物通过与这些场地上的其他光合作用植物(如针叶树)的真菌链接获得全部或部分C，(3)研究极端土壤的养分动员潜力以及真菌在植物养分动员方面的作用。这项研究将使用先进的显微镜来表征菌根，使用分子技术直接扩增和分析来自根的部分真菌DNA，并使用酶分析来测量养分动员活性。由此，我们可以鉴定真菌，计算菌根丰度，估计群落多样性，并确定菌根真菌的功能和多样性以及相关的针叶树生长适应性特征是否可能受到极端土壤因素的影响。这项研究将提供加拿大西部蛇形景观根际过程的基本信息。结果将涉及共生协会在维持这些生态系统中的重要性，菌根真菌适应极端土壤的弹性和能力，以及它们在保护或重建生物多样性植物栖息地方面的相关性。

Mycorrhizas are obligate symbioses between diverse fungi and the roots of most plants; they are critical to nutrient and energy exchange in belowground forest ecosystems. In part, the fungi facilitate plant nutrient and water uptake, and diminish toxic metal effects; in exchange, plants provide fungi with photosynthetic carbon (C). This proposal tests selection pressures related to physical, chemical, and biological properties of extreme soils on mycorrhizal fungi in serpentine landscapes. Globally, serpentine ecosystems support strikingly different, often unique, plant communities; however, we know little about the soil biology processes that support these systems, or how root-associated fungi may facilitate plant survival and adaptation. Using greenhouse and field studies, I will (1) assess root-fungal symbionts and seedling growth of conifers that are adapted to both serpentine and non-serpentine sites (including whitebark pine, a species that occurs only at high elevation and is 'endangered' in BC (COSEWIC), (2) assess the mycorrhizal structure, fungal identity and role of understory myco-heterotrophic plants that acquire all or part of their C via fungal links to other photosynthetic plants, such as conifers, on these sites, (3) examine the nutrient mobilization potential of extreme soils and the role of fungi on nutrient mobilization for plant use. The study will use advanced microscopy to characterize mycorrhizas, molecular techniques to directly amplify and analyze a portion of the fungal DNA from roots, and enzyme assays to measure nutrient mobilization activity. From this, we can identify fungi, calculate mycorrhizal abundance, estimate community diversity, and determine if the function and diversity of mycorrhizal fungi, and related growth adaptive traits of conifers, may be influenced by extreme soil factors. The study will provide fundamental information on rhizosphere processes in serpentine landscapes in western Canada. Results will address the importance of symbiotic associations in sustaining these ecosystems, the resilience and ability of mycorrhizal fungi to adapt to extreme soils, and their relevance in the conservation or re-establishment of biologically diverse plant habitats.