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

不列颠哥伦比亚省蛇纹石生态系统菌根系统对极端土壤因素的多样性和功能适应

• 批准号: 170632-2011
• 负责人: Massicotte, Hugues
• 金额: $ 1.97万
• 依托单位: University of Northern British Columbia
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2013
• 资助国家: 加拿大
• 起止时间: 2013-01-01 至 2014-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=522830
• 关键词: Diversity; functional; adaptation; mycorrhizal; systems

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.

菌根是多种真菌与大多数植物根系之间的专性共生体，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）。该提案测试了与蛇纹石景观中菌根真菌的极端土壤的物理，化学和生物学特性相关的选择压力。在全球范围内，蛇形生态系统支持惊人的不同，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，或者根相关真菌如何促进植物生存和适应。利用温室和田间研究，我将（1）评估适应蛇形和非蛇形场地的针叶树的根真菌共生体和幼苗生长（包括白皮松，一种只在高海拔地区出现的物种，在BC（COSEWIC）中是“濒危”的，（2）评估菌根结构，真菌身份和作用的林下真菌异养植物，获得全部或部分的C通过真菌连接到其他光合植物，如针叶树，在这些网站上，（3）研究极端土壤的养分动员潜力和真菌在植物养分动员中的作用。该研究将使用先进的显微镜来表征菌根，分子技术直接扩增和分析根部真菌DNA的一部分，以及酶测定来测量营养动员活性。由此，我们可以识别真菌，计算菌根丰度，估计群落多样性，并确定是否菌根真菌的功能和多样性，以及相关的生长适应性的针叶树，可能会受到极端土壤因素的影响。这项研究将提供在加拿大西部的蛇纹石景观根际过程的基本信息。结果将解决共生协会在维持这些生态系统，适应极端土壤的菌根真菌的弹性和能力的重要性，以及它们在保护或重建生物多样性的植物栖息地的相关性。