Control of Boreal Forest Soil Decomposition Processes by Plant Secondary Compounds

植物产生大量的次生化学物质，这些化学物质对基本代谢不是必需的，但在防御、竞争和繁殖中起着重要作用。关于植物次生代谢物在生态系统过程中的作用，如碳循环和环境污染物的分解，人们知之甚少。酚类、类黄酮和单宁能抑制植物物质的分解。 这些化合物中的一些已被证明可以增强土壤中芳香族污染物的微生物降解。有趣的是，阿拉斯加的北方森林树木具有非常高的次生化合物浓度。北方森林也是全球碳预算的重要组成部分，储存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北方森林的长期研究地点，包括一些石油污染的田间小区，以测试的假设，某些植物次生化学物质抑制植物凋落物分解，而在同一时间促进污染物降解的微生物。植物次生化学、凋落物分解和污染物降解的综合分析将与表征土壤中微生物群落组成和功能的尖端分子方法相结合，这些土壤与一系列不同的北方森林树木有关，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生态系统过程和全球碳循环的后果的有价值的信息。对促进有机污染物降解的植物-化学品-微生物相互作用的新认识也将深入了解北方森林土壤对有机污染物的恢复能力，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。高级研究培训的机会将提供给阿拉斯加土著高中学生以及本科生和研究生和博士后研究员。公众将通过艺术家和科学家之间的合作互动产生的新颖艺术活动参与该项目的主题和发现。

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.