Mycorrhizal roots slow the decay of belowground litters in a temperate hardwood forest
Mycorrhizal roots slow the decay of belowground litters in a temperate hardwood forest
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DOI：
10.1007/s00442-021-05051-1
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发表时间：
2021-10-09
期刊：
影响因子：
2.7
通讯作者：
Phillips，Richard P.
中科院分区：
文献类型：
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作者：
Beidler，Katilyn;Oh，Young E.;Phillips，Richard P.
越来越多的证据表明，植物根系和菌根真菌，无论是活的还是死的，在土壤碳（C）循环中发挥着核心作用。根-菌根-微生物的相互作用可以抑制和增强凋落物的腐烂，其净结果取决于地下养分获取策略和土壤养分的有效性。我们测量的净效应的活根和菌根真菌的死根和真菌菌丝的腐烂，在硬木林占主导地位的糖枫（糖槭）或白色橡树（栎alba）树。允许根和真菌凋落物在根向内生长袋和根排除芯内分解。结合根对腐烂的影响，我们评估了觅食反应和根引起的土壤水分，氮（N）的有效性和酶活性的变化。1年后，枫树根产量增加，菌根真菌的定植减少腐烂凋落物的存在。此外，我们发现，积极觅食的根系抑制根凋落物的腐烂（-14%）比真菌凋落物（-3%）更强，橡树（-20%）比枫树根（-8%）对根腐烂的抑制更强。橡树根腐烂的抑制作用是最大的根也降低了土壤氮的有效性，这对应于水解酶活性的降低和氧化酶活性的增强。这些发现进一步加深了我们对根-菌根-微生物相互作用的背景依赖性驱动因素的理解，并表明这种相互作用在温带森林土壤有机质积累和周转中发挥了未被充分认识的作用。
There is increasing evidence that plant roots and mycorrhizal fungi, whether living or dead, play a central role in soil carbon (C) cycling. Root–mycorrhizal–microbial interactions can both suppress and enhance litter decay, with the net result dependent upon belowground nutrient acquisition strategies and soil nutrient availability. We measured the net effect of living roots and mycorrhizal fungi on the decay of dead roots and fungal hyphae in a hardwood forest dominated by either sugar maple (Acer saccharum) or white oak (Quercus alba) trees. Root and fungal litter were allowed to decompose within root-ingrowth bags and root-exclusion cores. In conjunction with root effects on decay, we assessed foraging responses and root induced changes in soil moisture, nitrogen (N) availability and enzyme activity. After 1 year, maple root production increased, and mycorrhizal fungal colonization decreased in the presence of decaying litter. In addition, we found that actively foraging roots suppressed the decay of root litter (− 14%) more than fungal litter (− 3%), and suppression of root decay was stronger for oak (− 20%) than maple roots (− 8%). Suppressive effects of oak roots on decay were greatest when roots also reduced soil N availability, which corresponded with reductions in hydrolytic enzyme activity and enhanced oxidative enzyme activities. These findings further our understanding of context‐dependent drivers of root–mycorrhizal–microbial interactions and demonstrate that such interactions can play an underappreciated role in soil organic matter accumulation and turnover in temperate forests.