Work

Mowing enhances the sensitivity of arbuscular mycorrhizal mycelial carbon pools to nitrogen enrichment in grassland ecosystem

Year: 2026

Type: article

Abstract: Arbuscular mycorrhizal (AM) fungi are pivotal mediators of plant nutrient acquisition and depend on host‐derived carbon (C). However, how plant C allocation to AM fungi responds to below‐ground (e.g. soil nutrient availability) and above‐ground drivers (e.g. plant C availability) remains poorly understood. We used a long‐term (2015–2023) factorial field experiment in a meadow steppe in northern China, with six N addition rates (0, 2, 5, 10, 20 and 50 g N m −2 yr. −1 ) crossed with mowing (mown vs. unmown) to test how N enrichment and mowing alter plant–fungus C allocation strategies. In 2023, plant and fungal biomass, C content and AM fungal community composition were quantified. In unmown plots, plants preferentially allocated C to roots while maintaining relatively stable C allocation to mycelium, although mycelium biomass declined with N addition. By contrast, mowing intensified plant P limitation and altered C allocation strategies, with declines in mycelium biomass becoming evident only under relatively high‐N levels (above 10 g N m −2 yr. −1 ). In mown plots, receiving low‐N inputs increased C allocation to mycelium, whereas at higher N inputs, soil acidification sharply reduced C transfer to fungi. Changes in C allocation were tightly associated with the abundance of the dominant taxon Glomus VT387. Synthesis . Together, our findings demonstrate that mowing mediates N addition effects on plant C allocation to AM fungi, thereby providing mechanistic insight into plant–microbial interactions in grassland subject to global change and management.

Source: Journal of Ecology

DOI: 10.1111/1365-2745.70429