Interaction between tannins and fungal necromass stabilizes fungal residues in boreal forest soils

Abstract

See also the Commentary on this article by Hättenschwiler et al., 223: 5–7.

The chitin connection of polyphenols and its ecosystem consequences

“…In agreement with the findings by Adamczyk et al . (), Bending & Read () showed overall reduced accessibility to organic N by mycorrhizal plants when tannins were present, but with important variations among species of plants and mycorrhizal fungi. We know of only one study that unequivocally showed a preferential access to N from tannin–protein complexes by the ericoid mycorrhizal (ERM) Rhodendron maximum when these complexes were formed by tannins from that particular plant species (Wurzburger & Hendrick, ).…”

Mycorrhizal types differ in ecophysiology and alter plant nutrition and soil processes

“…Subsequent studies demonstrated that chitin is decomposed relatively rapidly, whereas the glomeromycotan glomalin and EcM fungal melanins and other hydrophobic proteins (hydrophobins) depolymerise slowly (Drigo et al, 2012;. Recalcitrant residues of EcM and ErM fungal cell walls contribute much to boreal forest humus (Clemmensen et al, 2013), especially when complexed with root-derived tannins (Adamczyk et al, 2019). While the EcM fungal mycelium proliferates in organic soil horizons , the AM fungal mycelium is mostly distributed in upper mineral soil layers (interpretation of data in Toju et al, 2016) in forest ecosystems.…”

Above- and belowground linkages shape responses of mountain vegetation to climate change

“…On poorly weathered bedrock, SOM can even be entirely comprised of POM. High POM accumulation reflects slow litter decomposition due to low temperatures, the recalcitrant nature of plant residues with high contents of polyphenols (45)(46)(47), and the low abundance of soil fauna, especially earthworms, which limits the incorporation of litter into mineral soils (48). Particulate organic matter represents a soil C pool that is highly vulnerable to loss when plant inputs are altered through plant community shifts (e.g.…”

“…The herbaceous vegetation relies strongly on symbiotic associations with arbuscular mycorrhizae for nutrient supply (60). Soils below the shrubline are characterized by a thick organic layer, consisting of recalcitrant plant residues from dwarf shrubs and coniferous trees (46,47), with abundant ericoid and ectomycorrhizae, and free-living saprotrophs (41,46,54). The low abundance of soil fauna, especially of earthworms, impedes the physical incorporation of litter into mineral soils (48).…”