Kiers describes lab experiments on the trade between plants and the mycorrhizal fungi on their roots: plants send carbon, fungi send phosphorus. By tagging phosphorus with fluorescent quantum dots, her team could watch fungi route it to where it fetched the most carbon. She cautions that these are simplified lab setups, and that the fungi are discriminating rather than "punishing".
…again that the fungi were very good at discriminating, and they were giving more phosphorus to the plant that gave more carbon. And so, what you have there is this sort of reciprocal exploitation, in a sense, where both partners are very good at discriminating and choosing the correct partner.
So, when you describe an experiment where you sort of stack the deck by making it possible for one side of the arena to provide more of the goodies, and then the fungi reciprocate by favoring that one and providing more in return, that sounds very familiar to the way that people operate.
…the plant is able to provide more carbon in return. We had this incredible experiment where we used something called quantum dots, which are these like bright fluorescent nanoparticles that you can attach to phosphorus to really see: okay, how do the fungi move their phosphorus around these very complex networks? And we set up an experiment that I won't go into all of the details, but basically, what we documented was that the fungus was taking up phosphorus on a very rich side of the network and moving it actively all the way to the other side of the network where the plant was willing to pay more. So, actively moving resources to get a higher price.
It's really unbelievable. The idea that, like a poor plant that happens to be shaded, so it's not able to get the amount of sunlight it would like. It's not happy about being shaded, right? This thing is having trouble providing the carbon because of its sad condition, and it ends up getting…
Yeah, so we have to be careful about the word punishment. Shouldn't talk like that, right? Like, punish? No, not at all. You can go ahead. But I think discriminate because that's a choice. So, it's not like it's actively punishing anything. No, you're right. There is active punishment in nature as…
Wow, so you want to anthropomorphize here, of course, but it is fascinating that this can be done mindlessly to some extent. I mean, nobody really is going to have a good argument that fungi are consciously making decisions, but there's clearly something on the way towards that. There's attention…