Phosphorus addition increased carbon partitioning to autotrophic respiration but not to biomass production in an experiment with Zea mays

Abstract

Plant carbon (C) partitioning-the relative use of photosynthates for biomass production, respiration, and other plant functions-is a key but poorly understood ecosystem process. In an experiment with Zea mays, with or without arbuscular mycorrhizal fungi (AMF), we investigated the effect of phosphorus (P) fertilization and AMF on plant C partitioning. Based on earlier studies, we expected C partitioning to biomass production (i.e., biomass production efficiency; BPE) to increase with increasing P addition due to reduced C partitioning to AMF. However, although plant growth was clearly stimulated by P addition, BPE did not increase. Instead, C partitioning to autotrophic respiration increased. These results contrasted with our expectations and with a previous experiment in the same setup where P addition increased BPE while no effect on autotropic respiration was found. The comparison of both experiments suggests a key role for AMF in explaining these contrasts. Whereas in the previous experiment substantial C partitioning to AMF reduced BPE under low P, in the current experiment, C partitioning to AMF was too low to directly influence BPE. Our results illustrate the complex influence of nutrient availability and mycorrhizal symbiosis on plant C partitioning.

Phosphorus stress strongly reduced plant physiological activity, but only temporarily, in a mesocosm experiment with <i>Zea mays</i> colonized by arbuscular mycorrhizal fungi

“…These results are in line with the study by Řezáčová et al (2018), who reported photosynthetic upregulation following the establishment of mycorrhizal symbiosis. Also our follow-up experiment with a P gradient confirmed the important stimulating role of AMF for plant productivity and photosynthesis (see Ven et al, 2020b).…”

Biotic factors dominantly determine soil inorganic carbon stock across Tibetan alpine grasslands

“…The large plant residues incorporated into the topsoil provided substantial amounts of organic matter for microbial living and decomposition (Oelkers et al, 2015;Ven et al, 2020), which can stimulate microbial abundance and activities and promote microbial extracellular enzymes. These extracellular excretions play a fundamental role in microbial respiration and CO2 production, both of which stimulate silicate weathering and carbonate dissolution (Vicca et al, 2022).…”

Is the climate change mitigation effect of enhanced silicate weathering governed by biological processes?

“…Given that mycorrhizal fungi depend on their host for C, their influence on ESW is likely to be strongly related to plant activity and plant C allocation. Depending on soil conditions, plants can allocate substantial amounts of C to mycorrhizal fungi (Ven et al, 2020), and thereby stimulate their weathering activity, increasing the release of P and other mineral elements from the silicate minerals (Verbruggen et al, 2021).…”

“…Plants allocate substantial amounts of C belowground in the form of roots and exudates and through symbiosis with mycorrhizal fungi (Ven et al, 2019; Verlinden et al, 2018). Nutrient availability is a key driver of plant C allocation and plant C inputs to the soil are likely to be affected by silicate addition, although the magnitude and direction of the effect is expected to depend on environmental conditions (Litton et al, 2007; Poorter et al, 2012; Ven et al, 2020; Vicca et al, 2012). Especially soil nutrient status and plant growth responses to the silicate additions are expected to be important in this regard.…”