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

菌根是多种真菌和大多数植物的根之间的专性共生；它们对地下森林生态系统的养分和能量交换至关重要。在某种程度上，真菌促进植物养分和水分的吸收，并减少有毒金属的影响；作为交换，植物为真菌提供光合作用碳(C)。本方案测试了蛇形景观中极端土壤对菌根真菌的物理、化学和生物特性的选择压力。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知之甚少，也不知道与根相关的真菌如何促进植物的生存和适应。通过温室和野外研究，我将(1)评估适应蛇形和非蛇形地点的针叶树的根真菌共生体和幼苗生长情况（包括白皮松，一种只发生在高海拔地区的物种，在卑诗省（COSEWIC）处于“濒危”状态）；(2)评估林下真菌异养植物的菌根结构、真菌身份和作用，这些植物通过与其他光合植物（如针叶树）的真菌联系获得全部或部分C。(3)研究极端土壤的养分动员潜力和真菌在植物利用养分动员中的作用。该研究将使用先进的显微镜来表征菌根，分子技术来直接扩增和分析根部的一部分真菌DNA，酶分析来测量营养动员活性。由此，我们可以鉴定真菌，计算菌根丰度，估计群落多样性，并确定针叶树菌根真菌的功能和多样性以及相关的生长适应性状是否可能受到极端土壤因素的影响。该研究将为加拿大西部蛇形地貌的根际过程提供基础信息。结果将说明共生关系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恢复力和能力，以及它们在保护或重建生物多样性植物栖息地中的相关性。

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.