Taylor Andrew F S, Högbom Lars, Högberg Mona, Lyon Anthony J E, Näsholm Torgny, Högberg Peter
Department of Animal and Plant Sciences, University of Sheffield, PO Box 601, Sheffield, S10 2UQ, UK.
Department of Forest Ecology, SLU, S-901 83 Umeå, Sweden.
New Phytol. 1997 Aug;136(4):713-720. doi: 10.1046/j.1469-8137.1997.00788.x.
The N natural abundance and N concentrations of fruit bodies from 70 species (23 genera) of ectomycorrhizal fungi found in boreal forests are presented. Large intraspecific and intrageneric differences were found, e.g. 8.3‰ N in the species Dermocybe crocea and 12.6‰ in the genus Cortinarius. In addition, significant differences in both δ N and %N were found between different parts of fruit bodies, with cap material giving consistently higher values. Proteins and amino acids were enriched by 9.7±0.4‰ (mean ± 1 SE) relative to chitin, irrespective of the part of the fruit body examined. Chitin had δ N values similar to that of plant hosts. The higher δ N and %N values of the caps than of the stipes probably reflect a higher portion of proteins and amino acids in the caps. The δ N of mycorrhizal fungi can be a function of the N species used (organic N, NH , NO ), the depth of soil at which the mycelium occurs, and metabolic fractionations. The metabolic fractionations, e.g. potential transaminations during the flux of N from the soil through the fungus to the plant, make it difficult, at present, to make inferences about sources of N based on δ N values alone. No effect of sample drying temperature on δ values of fungal material was detected.
本文展示了在北方森林中发现的70种（23属）外生菌根真菌子实体的氮自然丰度和氮浓度。研究发现种内和属内存在较大差异，例如，黄皮丝膜菌（Dermocybe crocea）物种的氮含量为8.3‰，丝膜菌属（Cortinarius）的氮含量为12.6‰。此外，子实体不同部位的δN和%N均存在显著差异，菌盖部分的值始终较高。无论检查子实体的哪个部位，相对于几丁质，蛋白质和氨基酸的含量均富集了9.7±0.4‰（平均值±1标准误差）。几丁质的δN值与植物宿主的相似。菌盖的δN和%N值高于菌柄，这可能反映了菌盖中蛋白质和氨基酸的比例更高。菌根真菌的δN可能是所用氮物种（有机氮、NH 、NO ）、菌丝体所在土壤深度以及代谢分馏的函数。目前，由于代谢分馏，例如氮从土壤通过真菌流向植物过程中的潜在转氨作用，仅根据δN值很难推断氮的来源。未检测到样品干燥温度对真菌材料δ值的影响。
