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Earth's Systems / Biological processes / Terrestrial ecosystem functioning / Living soil system / Mycorrhizal fungi network / Mycorrhizal nutrient trade: phosphorus, nitrogen and carbon market / Reciprocal reward and sanctioning

Reciprocal reward and sanctioning

Plants and fungi reward partners who deliver more and penalize poor ones: plants give more carbon to roots hosting generous fungi and fungi give more phosphorus to roots paying more carbon. Arbuscules of low-delivery partners degenerate.

Boundary: where this process starts

Starts with: Plant allocates more carbon to roots hosting fungi that deliver more phosphorus

Boundary: where it ends

Ends after: Cheater fungi that take carbon without phosphorus lose colonization; Fungus allocates more phosphorus to roots that supply more carbon

PARTICIPANTSRESOURCESHost plantMycorrhizalfungiArbusculesCarbonPhosphorusPhosphateImpact +3 of 5. Click for details and evidence.Compare returnsImpact +3 of 5. Click for details and evidence.Fungus comparesImpact +3 of 5. Click for details and evidence.Carbon received raises P givImpact +3 of 5. Click for details and evidence.↻ reinforces · moderate · 0.4 Phosphorus recImpact -2 of 5. Click for details and evidence.Poor partners get lessImpact +3 of 5. Click for details and evidence.Cooperation stabilisedImpact +2 of 5. Click for details and evidence.Impact -2 of 5. Click for details and evidence.Fungal spread reducedPlant allocates more carbon to roots hosting fungi that deliver more phosphorus: uses up Carbonuses upFungus allocates more phosphorus to roots that supply more carbon: uses CarbonFungus allocates more phosphorus to roots that supply more carbon: uses PhosphorusLow-delivery arbuscules degenerate when plant phosphate transport fails: uses PhosphateCheater fungi that take carbon without phosphorus lose colonization: uses up Carbonuses upCheater fungi that take carbon without phosphorus lose colonization: uses Phosphorusallocated tophosphorus-deliveri…Carbon: allocated to phosphorus-delivering rootssupplied by root partnerCarbon: supplied by root partnerallocated tocarbon-supplying rootsPhosphorus: allocated to carbon-supplying rootstransport failuretriggers degenerationPhosphate: transport failure triggers degenerationtaken without returnCarbon: taken without returnnot delivered in returnPhosphorus: not delivered in returnStart: Plant and funguscompare returnsSTARTStart: Plant and fungus compare returnsEnd: Partner choicesettledENDEnd: Partner choice settledPlant allocates morecarbon to roots hostingfungi that deliver mo…👍2📄1Plant allocates more carbon to roots hosting fungi that deliver more phosphorusFungus allocates morephosphorus to rootsthat supply more carbon👍2📄1Fungus allocates more phosphorus to roots that supply more carbonLow-delivery arbusculesdegenerate when plantphosphate transpo…👍1📄1Low-delivery arbuscules degenerate when plant phosphate transport failsCheater fungi that takecarbon withoutphosphorus lo…📄1Cheater fungi that take carbon without phosphorus lose colonization
Line thickness = size of impact (1 to 5)% on a line = chance a fork takes that branch📄 = pieces of evidence on a stepNegative effectLoops backHypothesisResource used up (arrow into the step)Resource used, not used upResource made or released (arrow out of the step)
What am I looking at? The concepts on every map
Participant
Someone or something that takes part in a process or influences it: a plant, a microbe, a river, a machine, a force. Participants are the rows of a map.
Resource
Something a step uses or uses up: water, oxygen, sunlight, a tool. Each step has an arrow down to the resources it uses.
Step
One thing that happens in a process. Every step has at least one participant and carries evidence.
Decision fork
A step where the process can go several ways. Every outcome is labeled with a percentage, and the percentages add up to 100%. It is not limited to yes or no.
Loop
A line that carries the process back to an earlier step. We record whether it reinforces or balances, how strong it is (weak, moderate, strong), and its gain (0 to 1): the share of the effect that returns on each pass.
Size of impact
Every line says how much the earlier step affects the next one (1 to 5), in which direction (+, -, 0), and why. Thicker lines mean bigger impact.
Evidence
The support for a claim: a source and what it shows. Every step, line, change and vote needs it. Click any step or line to read its evidence.
Boundary
Where a process starts and where it ends. Every process, and every subprocess, has a start and an end.
Subprocess
A step that is itself a whole process, with its own boundary, steps and lines. Click a step marked ↘ to open it. Subprocesses nest as deep as the evidence goes.
Description
A plain-language summary of what a process is and what it covers.
Hypothesis
A proposed new connection between two parts of the map that nobody has linked. It carries a prediction, a way to test it, and a count of papers on each topic and on both. It is an unverified idea until someone tests it.

Every step, with its evidence

The same information as the map, as a list you can search and share. Click a participant or resource to see everywhere it appears.

Plant allocates more carbon to roots hosting fungi that deliver more phosphorus
Host plantCarbon
Evidence (1) · added by Ember
  • Kiers et al. 2011, Reciprocal rewards stabilize cooperation in the mycorrhizal symbiosis, Science 333:880-882: Host plant rewards the better fungal partner with more carbohydrate (confidence 0.9)
Fungus allocates more phosphorus to roots that supply more carbon
Mycorrhizal fungiPhosphorusCarbon
Evidence (1) · added by Ember
  • Kiers et al. 2011, Reciprocal rewards stabilize cooperation in the mycorrhizal symbiosis, Science 333:880-882: Fungus delivers more P to hosts offering more carbon, observed with 33P tracing in root organ cultures (confidence 0.85)
Low-delivery arbuscules degenerate when plant phosphate transport fails
ArbusculesHost plantPhosphate
Evidence (1) · added by Ember
  • Javot et al. 2007, A Medicago truncatula phosphate transporter indispensable for the arbuscular mycorrhizal symbiosis, PNAS 104:1720-1725: MtPT4 mutants show premature arbuscule collapse (confidence 0.9)
Cheater fungi that take carbon without phosphorus lose colonization
Mycorrhizal fungiCarbonPhosphorus
Evidence (1) · added by Ember
  • Kiers et al. 2011, Reciprocal rewards stabilize cooperation in the mycorrhizal symbiosis, Science 333:880-882: Sanctions penalize fungal partners that provide little P (confidence 0.7)