Nutrient transfer
To determine nutrient transport across the fungal network and into the
root growing in the focal compartment, we used a second subset of thein-vitro plates (A5: n =12, B12: n =8, Agg:n =12) in which we injected quantum-dot tagged apatite as a
fluorescently labeled phosphorus source in the partner root compartment.
We constructed green (490 nm) quantum-dot apatite by conjugating
hydroxyapatite with fluorescent quantum-dots following the technique
described in Whitesideet al. (2019). We injected 500 µL of a 126 mM phosphorus solution
to the partner compartment of each replicate (Fig. 1d), and harvested
these plates two weeks after quantum-dot apatite injection. This allowed
us to quantify phosphorus transfer from one root compartment to another
via the mycorrhizal network.