DOI: 10.5061/dryad.v15dv421p
title: Plant choice between arbuscular mycorrhizal fungal species results in increased plant P acquisition

description: Arbuscular mycorrhizal fungi (AMF) are plant root symbionts that provide
 phosphorus (P) to plants in exchange for photosynthetically fixed carbon
 (C). Previous research has shown that plants – given a choice among AMF
 species – may preferentially allocate C to AMF species that provide more
 P. However, these investigations rested on a limited set of plant and AMF
 species, and it therefore remains unclear how general this phenomenon is.
 Here, we combined 4 plant and 6 AMF species in 24 distinct plant-AMF
 species compositions in split-root microcosms, manipulating the species
 identity of AMF in either side of the root system. Using 14C and 32P/33P
 radioisotope tracers, we tracked the transfer of C and P between plants
 and AMF, respectively. We found that when plants had a choice of AMF
 species, AMF species which transferred more P acquired more C. Evidence
 for preferential C allocation to more beneficial AMF species within
 individual plant roots was equivocal. However, AMF species which
 transferred more P to plants did so at lower C-to-P ratios, highlighting
 the importance both of absolute and relative costs of P acquisition from
 AMF. When plants had a choice of AMF species, their shoots contained a
 larger total amount of P at higher concentrations. Our results thus
 highlight the benefits of plant C choice among AMF for plant P
 acquisition.
description: # Overview We grew plants in split root microcosms and manipulated the
 arbuscular mycorrhizal fungal (AMF) species identity in both sides of
 these microcosms. Our intent was to evaluate whether a common mechanism of
 symbiotic control among plant species is the preferential allocation of
 carbon (C) to higher quality AMF species when plants have options of AMF
 species in separate parts of their root systems. #
 biomass\_and\_nutrients.csv --- Plant biomass (dry) as total and
 partitioned into nutrients, both fractional and total nutrient content for
 phosphorus (P) and nitrogen (N). Data are given for each species pool and
 the associated plant species x AMF species compositions ## Description of
 the data and file structure | Variable | Description | units | | --------
 |
 ---------------------------------------------------------------------------------------------------------- | ----- | | pool | pool of plant and AMF species used | n/a | | plantsp | plant species genus names | n/a | | amfcomp | AMF species composition | n/a | | choice | Whether plants have choice between two AMF species or are restricted to interact with a single AMF species | n/a | | mass | Shoot biomass of the host plant | g | | pfrac | Fractional P content of host plant shoot biomass | g/g | | nfrac | Fractional P content of host plant shoot biomass | g/g | | totp | Total P content of host plant shoot biomass | mg | | totn | Total N content of host plant shoot biomass | mg | ### Factor levels | plantsp | Description | | --------- | --------------------- | | holcus | *Holcus lanatus* | | lolium | *Lolium multiflorum* | | plantago | *Plantago lanceolata* | | trifolium | *Trifolium pratense* | | amf\* | Description | | ----- | ---------------------------- | | fm | *Funneliformis mosseae* | | gd | *Glomus diaphanum* | | sc | *Septoglomus constrictum* | | cc | *Claroideoglomus claroideum* | | dc | *Diversispora celata* | | ri | *Rhizophagus invermaius* | *This applies equally to amf_focal, amf_opposite and amfcomp | choice | Description | | ---------- | ------------------------------------------------------------------------------------------------ | | choice | Plants have two different AMF species in the spatially separated portions of their root systems | | no\_choice | Plants have the same exact AMF species in the spatially separated portions of their root systems | # GCA.csv --- We estimated the quality of AMF species associated with our host plants in order to assess whether plants allocated more C (measured as <sup>14</sup>C) to higher quality AMF. We achieved this via a mechanical diallel approach, taken from biodiversity experiments. We estimated general combining ability (GCA) for each plant x AMF species, for both total P (i.e. P acquired potential via direct root P uptake + AMF P uptake mechanism) and radiolabeled P (either <sup>32</sup>or<sup>33</sup>P; i.e. P acquired via AMF P uptake mechanism) ## Description | Variable | Description | units | | --------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ | -------------------- | | pool | pool of plant and AMF species used | n/a | | plantsp | plant species genus names | n/a | | amf | AMF species | n/a | | totp\_gca | Total plant shoot P general combining ability (GCA), estimate of AMF species quality. Estimated for each plant species x AMF species combination. | mg | | p\_gca | Radiolabeled shoot P (either <sup>32</sup> or <sup>33</sup>P; acquired from AMF transfer) general combining ability (GCA), estimate of AMF species quality. Estimated for each plant species x AMF species combination. | kBq (kilobecquerels) | ### Factor levels | plantsp | Description | | --------- | --------------------- | | holcus | *Holcus lanatus* | | lolium | *Lolium multiflorum* | | plantago | *Plantago lanceolata* | | trifolium | *Trifolium pratense* | | amf\* | Description | | ----- | ---------------------------- | | fm | *Funneliformis mosseae* | | gd | *Glomus diaphanum* | | sc | *Septoglomus constrictum* | | cc | *Claroideoglomus claroideum* | | dc | *Diversispora celata* | | ri | *Rhizophagus invermaius* | *This applies equally to amf_focal, amf_opposite and amfcomp # radioisotopes.csv --- Radioactive isotopic tracers applied to plants and associated arbuscular mycorrhizal fungi (AMF) within a split root microcosm. Our intent was to identify patterns of resource transfer (plant carbon (C) and AMF phosphorus (P)) between several different combinations of plant hosts and AMF species (between 1 and 2 species). ## Description | Variable | Description | units | | ------------- | ----------------------------------------------------------------------------------------------------------------------------------- | -------------------- | | pool | pool of plant and AMF species used | n/a | | plantsp | plant species genus names | n/a | | amf\_focal | focal AMF species | n/a | | amf\_opposite | AMF species in opposing side of the microcosm | n/a | | amfcomp | AMF species composition | n/a | | c | <sup>14</sup>C transferred to focal AMF species | kBq (kilobecquerels) | | p | <sup>32</sup> or <sup>33</sup>P transferred from focal AMF species to plant | kBq (kilobecquerels) | | cp | <sup>14</sup>C:<sup>32/33</sup>P, i.e. C transferred from plants to focal AMF species relative to P acquired from focal AMF species | kBq (kilobecquerels) | ### Factor levels | plantsp | Description | | --------- | --------------------- | | holcus | *Holcus lanatus* | | lolium | *Lolium multiflorum* | | plantago | *Plantago lanceolata* | | trifolium | *Trifolium pratense* | | amf\* | Description | | ----- | ---------------------------- | | fm | *Funneliformis mosseae* | | gd | *Glomus diaphanum* | | sc | *Septoglomus constrictum* | | cc | *Claroideoglomus claroideum* | | dc | *Diversispora celata* | | ri | *Rhizophagus invermaius* | *This applies equally to amf_focal, amf_opposite and amfcomp