Saprotrophic Responses by Ectomycorrhizal Fungi

点击翻译按钮获取中文摘要

9318568 Miller Many studies have detected enzymes in fungi (fungi that are symbiotically associated with the roots of trees) that may decompose organic matter in laboratory studies. Other studies imply that these symbiotic fungi are not capable of such decomposition in the field even though they may outgrow true saprotrophic fungi in the soil. Several possibilities exist for this apparent contradiction. The symbiotic association may alter the behavior of mycorrhizal fungi so that enzyme production is not possible. Another possibility is that ectomycorrhizal fungi may only be able to decompose organic matter during times when sugars produced by their host are not being produced in sufficient quantities. At such times, the saprotrophic machinery of mycorrhizal fungi may be able to obtain energy along with required mineral elements from organic substrates. A third possibility is that at least some reports of enzymatic activity in the laboratory are subject to criticism because the research has been accomplished under conditions that are very different from what would most likely be encountered by these fungi. We propose to examine the mechanisms of ectomycorrhizal fungi that may allow them to better compete with saprotrophic fungi. We will accomplish this by conducting experiments in the laboratory using specially designed root chambers that allow growth and manipulation of a portion of the fungus separate from the roots and rooting substrate while still in symbiosis with the tree. This approach will allow us to investigate the saprotrophic reposes by ectomycorrhizal fungi at a level that heretofore has not been achieved. ***