Characterizing the chemical changes in fungal necromass as it degrades, particularly over short time intervals (days to weeks), is critical to clearly understanding how this organic matter source contributes to various belowground carbon and nutrient pools. Using a range of chemical analyses, we assessed the degradation of four types of ectomycorrhizal fungal necromass from three species differing in biochemical composition. Samples were buried in a forest in Minnesota, USA and harvested at eight time points over a 90-day incubation period (1, 2, 4, 7, 14, 28, 60, 90 days). Three of the necromass types lost greater than 50% of their initial mass in the first seven days, but mass loss plateaued for all four types at later harvests, and after 90 days, none of the samples were completely degraded. Relative to undegraded necromass, degraded necromass consistently contained a lower relative abundance of aliphatic compounds and a higher relative abundance of carbohydrates, sterols, and aromatic compounds. For three of the four necromass types, nitrogen content was lower after 90 days of degradation and FTIR spectra revealed distinct peaks broadening from day 0 to day 90. While melanin content significantly slowed degradation within species, differences in degradation rates across species were more closely aligned with initial nitrogen content. Collectively, our results indicate that the rapid mass loss of dead fungal mycelium is accompanied by a wide range of changes in necromass chemistry, likely contributing to both short-term soil nutrient and longer-term carbon pools.

表征真菌坏死在降解过程中的化学变化，尤其是在短时间间隔（几天到几周）内，对于清楚了解这种有机物源如何促进各种地下碳和养分库至关重要。使用一系列化学分析，我们评估了生化成分不同的三种物种对四种类型的外生菌根真菌坏死的降解。样品被埋在美国明尼苏达州的森林中，并在90天的潜伏期（1、2、4、7、14、28、60、90天）的八个时间点收获。在开始的7天中，三种坏死损失了其初始质量的50％以上，但是在随后的收获中，这四种类型的质量损失均达到了稳定水平，并且在90天后，没有一个样品完全降解。相对于未降解的坏死，降解的坏死瘤始终包含较低的脂肪族化合物相对丰度和较高的碳水化合物，固醇和芳香族化合物相对丰度。对于四种坏死类型中的三种，降解90天后氮含量较低，并且FTIR光谱显示从第0天到第90天有明显的峰展宽。虽然黑色素含量显着减缓了物种内部的降解，但物种间的降解速率差异更加紧密初始氮含量。总的来说，我们的结果表明，死亡真菌菌丝体的快速质量损失伴随着坏死化学的广泛变化，可能会导致短期土壤养分和长期碳库的增加。