Plant carbohydrate depletion impairs water relations and spreads via ectomycorrhizal networks

Gerard Sapes, Patrick Demaree, Ylva Lekberg, Anna Sala

Research output: Contribution to journalArticlepeer-review

46 Scopus citations


Under prolonged drought and reduced photosynthesis, plants consume stored nonstructural carbohydrates (NSCs). Stored NSC depletion may impair the regulation of plant water balance, but the underlying mechanisms are poorly understood, and whether such mechanisms are independent of plant water deficit is not known. If so, carbon costs of fungal symbionts could indirectly influence plant drought tolerance through stored NSC depletion.
We connected well‐watered Pinus ponderosa seedling pairs via ectomycorrhizal (EM) networks where one seedling was shaded (D) and the other kept illuminated (LD) and compared responses to seedling pairs in full light (L). We measured plant NSCs, osmotic and water potential, and transfer of 13CO2 through EM to explore mechanisms linking stored NSCs to plant water balance regulation and identify potential tradeoffs between plant water retention and EM fungi under carbon‐limiting conditions.
NSCs decreased from L to LD to D seedlings. Even without drought, NSC depletion impaired osmoregulation and turgor maintenance, both of which are critical for drought tolerance. Importantly, EM networks propagated NSC depletion and its negative effects on water retention from carbon stressed to non-stressed hosts.
We demonstrate that NSC storage depletion influences turgor maintenance independently of plant water deficit and reveal carbon allocation tradeoffs between supporting fungal symbionts and retaining water.
Original languageEnglish (US)
JournalNew Phytologist
StatePublished - Dec 28 2020


  • carbon starvation
  • drought
  • ectomycorrhizas
  • fungal networks
  • nonstructural carbohydrate
  • osmotic potential
  • Pinus ponderosa
  • turgor

PubMed: MeSH publication types

  • Journal Article
  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, Non-U.S. Gov't


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