Control of Boreal Forest Soil Decomposition Processes by Plant Secondary Compounds

植物产生大量多种多样的次生化学物质，这些化学物质不是基本新陈代谢所必需的，但在防御、竞争和繁殖中发挥着重要作用。人们对次生植物代谢物在碳循环和环境污染物分解等生态系统过程中的作用知之甚少。酚类、类黄酮类和单宁可以抑制植物物质的分解。其中一些相同的化合物已被证明可以促进土壤中芳香污染物的微生物降解。有趣的是，阿拉斯加的北方林木含有非常高浓度的次生化合物。北方森林也是全球碳预算的重要组成部分，容纳了世界上近三分之一的植被碳和土壤碳。这项研究将利用阿拉斯加和芬兰的长期研究北方森林地点，包括一些被石油污染的田地，来检验某些植物次生化学物质抑制植物凋落物分解，同时促进微生物降解污染物的假设。植物次生化学、凋落物分解和污染物降解的综合分析将与前沿的分子方法相结合，以表征与一系列不同北方林木相关的土壤中微生物群落的组成和功能。这项研究将产生关于植物和微生物之间的化学相互作用以及对生态系统过程和全球碳循环的影响的有价值的信息。对促进有机污染物降解的植物-化学-微生物相互作用的新见解也将提供对北方森林土壤对有机污染物的适应能力的洞察，并可能导致使用本地植物减轻偏远寒冷地区污染的负担得起的方法。将向阿拉斯加土著高中生以及本科生和研究生以及博士后研究员提供高级研究培训的机会。公众将通过艺术家和科学家之间的合作互动产生的新颖的艺术活动来参与这个项目的主题和发现。

Plants produce a vast and variable array of secondary chemicals that are not essential for basic metabolism, yet play important roles in defense, competition, and reproduction. Considerably less is known about the role of secondary plant metabolites in ecosystem processes like carbon cycling and the breakdown of environmental pollutants. Phenolics, flavonoids, and tannins can inhibit the decomposition of plant matter. Some of these same compounds have been shown to enhance the microbial degradation of aromatic contaminants in soil. Interestingly, boreal forest trees in Alaska possess remarkably high concentrations of secondary compounds. The boreal forest is also a critical component of the global carbon budget, housing nearly one third of the World's vegetation carbon and soil carbon. This study will make use of long-term study boreal forest sites in Alaska and Finland, including some petroleum-contaminated field plots, to test the hypothesis that certain plant secondary chemicals inhibit plant litter decomposition, while at the same time promoting pollutant degradation by microorganisms. Comprehensive analyses of plant secondary chemistry, litter decomposition, and contaminant degradation will be integrated with cutting-edge molecular approaches for characterizing microbial community composition and function in soils associated with an array of different boreal forest trees.This study will generate valuable information about the chemical interactions between plants and microbes and the ramifications for ecosystem processes and global carbon cycling. New insights into plant-chemical-microbial interactions that promote organic contaminant degradation will also provide insight into the resilience of boreal forest soils to organic contaminants, and may lead to affordable methods for mitigating contamination in remote, cold regions using native plants. Opportunities for advanced research training will be provided to Alaska Native high school students as well as undergraduate and graduate students and a postdoctoral researcher. The public will be engaged with the themes and findings of this project through novel arts events resulting from collaborative interactions between artists and scientists.