Plants talk to each other using an internet of fungus | Hacker News Reader

Plants talk to each other using an internet of fungus

bbc.com

140 pointsdragonbonheur31 comments

Slime Mold Physarum Finds the Shortest Path in a Maze - https://www.youtube.com/watch?v=czk4xgdhdY4

From that video I found this video, which has a similar treatment of finding the shortest path in a maze as well as some more impressive feats (like recreating the subway system of Tokyo).

https://www.youtube.com/watch?v=lls27hu03yw

Pretty a-mazing.

"Simard now believes large trees help out small, younger ones using the fungal internet. Without this help, she thinks many seedlings wouldn't survive."

This feels backwards to me. It seems more likely that the fungus is the one doing this, monitoring the condition of trees it touches and equalizing nutrients to maximize their survivability — and its own, since it lives among their roots.

I'm with you.

In "The Omnivore's Dilemma", Michael Pollan mentions a type of mushroom that blooms only after a forest fire. It has a symbiotic relationship with the nearby trees, and when they die, it blooms and releases its spores to fly off in search of other places to live.

That's an interesting point of view. Maybe the Network is the computer after all. Sun had it right.

Whatever the message being passed along, the network doesn't seem to be harmed at all. Maybe it is the prime beneficiary of this interconnection and passes chemicals around just to make sure it has the resources of the trees at its disposal in the future. And it manages those resources carefully to ensure they don't use up all the nutrients in the soil too fast.

Interesting point of view.

McLuhan:

> Physiologically, man in the normal use of technology (or his variously extended body) is perpetually modified by it and in turn finds new ways of modifying his technology. Man becomes, as it were, the sex organs of the machine world, as the bee of the plant world, enabling it to fecundate and evolve ever new forms.

Michael Pollan in one of his speeches, called corn one of the most successful species on Earth via its utilization of humans to facilitate its propagation.

Isn't that a fairly arbitrary philosophical distinction? I'm not sure we can say which organism intends to distribute the resources, since that's a fairly anthropocentric concept. I suppose one could ask whether the relationship between the large tree and the fungus is beneficial to the large tree despite the large tree losing some resources, but the answer seems to be yes.

Well, if you look at it from the ecosystem's standpoint, it's just a check or balance. But the fungus is, like pretty much all life, acting in its own self-interest. The trees don't even have to "consent" to this — it seems that it's more likely that a fungus is acting as a sort of benevolent parasite than that very different trees have established some kind of cross-platform messaging system that uses a third, very different type of organism as a mediator. It's just simpler to me to think that the fungus is acting on its own and it ends up being a net gain for everyone involved.

>The trees don't even have to "consent" to this

The trees benefit as well — the fungus gives minerals, and in exchange the trees give sugars. It's a transaction. https://en.wikipedia.org/wiki/Mycorrhiza#Sugar-water.2Fminer...

>benevolent parasite

The word you're looking for is "symbiosis".

It seems like you're trying hard to view this through a lens of competition instead of cooperation.

I'm aware of the word, I chose to say something different.

Why is competition a "lens" I must see through?

(Speaking of anthropocentrism) The day before I saw this story I remarked to my kids that trees can think. It's just very slow - might take 20 years to form a thought.

I'm still not sure how serious I was but it makes you wonder about where and how many qualitatively different levels of "thinking" there are between trees, dogs and us.

So just to clarify, this network is used primarily for transferring nutrients, chemicals and the like? Not signals(data). Does the fact that plants respond differently to differing stimuli imply that they have some information processing mechanism?

The fact that they feed and use the chemistry from their metabolic pathways to drive things like plant locomotion and tropism is a clear indicator for "information" processing. The information in this case is chemistry as a result of their surrounding, and processing is the metabolic pathway and beyond.

Different species of bacteria have been shown to "communicate" via chemical signals, too. It's obviously not cognitive communication, but mating/threat displays between lower order animals can be considered to be just responses to stimuli as well.

Communication between plants may not be cognitive, but it's still the transfer of information.

What's obvious about it? And what exactly do you mean by "cognitive communication"?

I mean communication between two organisms capable of cognition, i.e. language, mating displays, or other forms of communication that require a brain capable of interpretation.

Chemicals are signals. For example, a hormone is pretty much by definition a signaling chemical.

Plants most definitely have information processing. The entire process of 20th century computation reveals that you can get 'intelligence' from really stupid things (NAND gates) - conversing that we can have computation (and all that implies) from a variety of different substrates (neurons, mechanical relays, semi conductors, quantum bits, etc). People tend to get panicky and start delineating things so that they can restrict plants from 'having thought' but its all pretty silly.

I see, I understand that fundamentally chemicals are signals. I guess what I meant was: could they use this basic "computation model" to pass complex messages? For example, provided a plant is aware of it's distance from another nearby connected plant, could it indicate via chemical signals that the soil is richer here, grow your roots in this direction, conversely, the soil is toxic here, grow your roots in the opposite direction?

That kind of interplant communication is subject to a prisoners'-dilemma-like payoff matrix though. Yes, a plant species evolving a co-operative strategy like that will do well, in aggregate, but individual plants which 'defect' and advertise to other plants that the nutritious soil they have found is poisonous and that other plants should keep away will outcompete its peers - so defector genes will prosper in the population - except in the face of plants which ignore their peers' chemical signals.

Overall, seems likely to be selected against as a strategy for individual organisms.

I think that the effectiveness of the strategy will depend on the specific plant's pollination/seed dispersal mechanism. And it gets really weird when you consider that you can have plants that over multiple seedling generations (years really) that have a mix of clonal colonies and sexually reproduced offspring dispersed around them.

To the original question, one obvious difficulty is considering how a mechanism encoding directionality in a chemical signal can evolve. It's certainly possible that these fungal networks are weakly directional, and it's also possible for a plant to evolve some sort of gradient sensing mechanism if its root network is sufficiently wide, but it -seems- unlikely. I would totally love to see if we can find an example of it though - it would be sooo cool.

What about a population of 100 such plants where the defector gene is very unlikely to surface for whatever reason, and the plants are able to cooperate and that population becomes stronger for it, versus a population of 100 similar plants except the defector gene might be rather likely to show up, making the population weaker.

Couldn't the population without the defector gene, eventually outcompete and extinguish the population where it can appear?

They're referring to chemical signalling of some kind when they use the word 'signal'.

Chemical signalling of various kinds is very common in all kingdoms of life; examples in animals are hormones (circulated in the bloodstream for communication between organs), pheromones (circulated in the air for signalling between organisms), and neurotransmitters (emitted in the gap between synapses and dendrites for signalling activation of a neuron).

Fascinating. I had known for some time that oak trees will commingle their roots, forming an oak internet. In good times, this helps smaller trees become better established through resource-sharing with mature trees. Unfortunately, the network doesn't just pass beneficial resources; it also passes the oak wilt pathogen, so if one oak tree gets the wilt, it's a pretty good bet that all the others in the immediate vicinity will get it too.

Sounds like an Orson Scott Card plot from Xenocide i.e. Descolada.

Funny enough it was also a plot point in The Happening, supposedly the plants had a network to kill humans off by dispersing a defensive component causing a plague.

I thought of that as well. Too bad it isn't a network with low latency.

This reminds me of Alan Kay's thesis of similarities between biological systems and object systems. Robustness is gained by dividing things into large amounts of small cells communicating in an unrestricted graph topology. This is basically how networks of REST speaking nodes work as well. All three of these systems share more similarities than one might immediately realise. The big idea is messaging.

This potentially quite a profound result -- especially if cooperative behaviors and information processing capabilities comparable to that of, say, insects or small animals (in the sense of Animalia) can be quantitatively assessed.

PBS documentary "What Plants Talk About" https://www.youtube.com/watch?v=rrG-42uCDj4

Wonder what sort of neutrality situation they have.

Reply on news.ycombinator.com