Root and mycorrhizal fungal foraging responses to fruit removal in apple trees

Emily K. Lavely, Jianghong Zhang, Thomas S. Adams, David R. Bryla, Jared L. DeForest, Richard P. Marini, Robert Crassweller, David M. Eissenstat

Research output: Contribution to journalArticle

Abstract

Background and aims: Root and mycorrhizal fungal foraging in nutrient-rich patches is an energy-intensive process, and shifts in carbon (C) availability may affect foraging strategies. We hypothesize that when trees are C limited, they will prioritize root and mycorrhizal hyphal growth in nutrient-rich soil patches. Methods: Apple (Malus domestica Borkh.) trees with fruit were compared to trees with fruit removed to investigate the effect of reproductive effort and associated shifts in belowground C availability on root and arbuscular mycorrhizal (AM) fungal growth in unfertilized soil and localized nitrogen (N)-rich patches (containing inorganic or organic nitrogen). Results: Across nutrient treatments, fruit removal enhanced root production compared to fruiting trees. In fruiting trees, about four times more roots proliferated in the inorganic-N patch than in unfertilized soil or the organic-N patch. However, in trees with fruit removal, root proliferation was similar among nutrient treatments. Arbuscular mycorrhizal extramatrical-hyphal biomass was not affected by fruit removal but was greater in the organic-N patch than the inorganic-N patch or unfertilized soil. Fruit removal and N addition had modest effects on AM fungal colonization of apple roots and no effect on non-mycorrhizal fungal colonization. Conclusions: Root and AM foraging for nutrients should be considered in the context of C availability. Apple trees may manipulate root foraging more than AM fungal foraging when C belowground is constrained.

Original languageEnglish (US)
Pages (from-to)401-416
Number of pages16
JournalPlant and Soil
Volume431
Issue number1-2
DOIs
StatePublished - Oct 1 2018

All Science Journal Classification (ASJC) codes

  • Soil Science
  • Plant Science

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