Favorable effect of mycorrhizae on biomass production efficiency exceeds their carbon cost in a fertilization experiment

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Abstract

Biomass production efficiency (BPE), the ratio of biomass production to photosynthesis, varies greatly among ecosystems and typically increases with increasing nutrient availability. Reduced carbon partitioning to mycorrhizal fungi (i.e., per unit photosynthesis) is the hypothesized underlying mechanism, as mycorrhizal abundance and plant dependence on these symbionts typically decrease with increasing nutrient availability. In a mesocosm experiment with Zea mays, we investigated the effect of nitrogen (N) and phosphorus (P) addition and of mycorrhizal inoculation on BPE. Photosynthesis and respiration were measured at mesocosm scale and at leaf scale. The growth of arbuscular mycorrhizal fungi (AMF) was assessed with ingrowth bags while also making use of the difference in δ13C between C4 plants and C3 soil. Mesocosms without AMF, that is, with pasteurized soil, were used to further explore the role of AMF. Plant growth, photosynthesis, and BPE were positively affected by P, but not by N addition. AMF biomass also was slightly higher under P addition, but carbon partitioning to AMF was significantly lower than without P addition. Interestingly, in the absence of AMF, plants that did not receive P died prematurely. Our study confirmed the hypothesis that BPE increases with increasing nutrient availability, and that carbon partitioning to AMF plays a key role in this nutrient effect. The comparison of inoculated vs. pasteurized mesocosms further suggested a lower carbon cost of nutrient uptake via AMF than via other mechanisms under nutrient rich conditions.

Detaljer

Författare
  • Melanie S. Verlinden
  • Arne Ven
  • Erik Verbruggen
  • Ivan A. Janssens
  • Håkan Wallander
  • Sara Vicca
Enheter & grupper
Externa organisationer
  • University of Antwerp
Forskningsområden

Ämnesklassifikation (UKÄ) – OBLIGATORISK

  • Ekologi
  • Botanik

Nyckelord

Originalspråkengelska
Sidor (från-till)2525-2534
TidskriftEcology
Volym99
Utgåva nummer11
Tidigt onlinedatum2018 sep 14
StatusPublished - 2018
PublikationskategoriForskning
Peer review utfördJa