Plants “panic” when it rains
phys.org
phys.org
https://www.pnas.org/content/early/2019/10/25/1911758116
>“As to why plants would need to panic when it rains, strange as it sounds, rain is actually the leading cause of disease spreading between plants,” said University of Western Australia’s Professor Harvey Millar, co-author of the study.
“When a raindrop splashes across a leaf, tiny droplets of water ricochet in all directions. These droplets can contain bacteria, viruses, or fungal spores.”
“The sick leaves can act as a catapult and in turn spread smaller droplets with pathogens to plants several feet away. It is possible that the healthy plants close by want to protect themselves,
I'm torn because maybe I wouldn't have read the article without the needless anthropomorphization. Plants are awesome and interesting to me because they're so planty and not animaly.
It's different from a mere adrenal response that has short term gain at long term risk.
Adrenaline makes you jump higher. Panic makes you jump off a cliff.
At least in my personal dictionary.
Also, it would seem that the panic response is evolved for the benefit of the flock, not the individual, as it spreads rapidly; if one person panics, more will follow suit.
Yes. When something is panic inducing.
Note that the bad connotations of panic are for not panic worthy situations (e.g. don't panic when you just lost your wallet, etc).
But when chased by a predator, a panic response is a good, and evolutionary created, way, to get from 0-60 mph adrenaline and speed wise...
A gazelle doesn't sit still and weigh the situation calmly. It panics and starts to run for its life...
Once you decide to move, run (if that wasn't an instinctive response), then panic is over and action has ensued.
It's the "beachball of doom" bit that happens when the you spot the lion. Do I fight, or hide, or run, ... {computing best response, please wait} ... it's the wait in that parenthetical bit where your supervisory control systems say "argh, this is taking too long, in going to get eaten".
Surely?
The dictionary.com definition has it as "overwhelming fear that causes a sudden hysterical or irrational behaviour". Running from a predator is rational, or instinctive.
Well, complains should be directed to evolution.
>Being chased by a predator and you run? Are humans likely the fastest animals?
Depends on the predator, for humans it will many times be other humans (or other homo species), and the extra boost panic mode gives you can very much help. Besides you don't have to merely run, you can run and hide, run and jump on some tree, etc.
>The only way out is to outsmart it and you can't do that if you're panicking.
You don't care much for outsmarting and subtle strategy when it's life or death either.
From Wikipedia:
"An evolutionary psychology explanation is that early animals had to react to threatening stimuli quickly and did not have time to psychologically and physically prepare themselves. The fight or flight response provided them with the mechanisms to rapidly respond to threats against survival."
If I come at you screaming with a knife would you sit and think how to outsmart me for a while, or start to panic / hide behind something / run trying to escape/avoid me? I'd like to see someone try the former...
>The word itself carries an undesirable connotation and is never - by definition - the best course of action
That's at the human cultural level, where it's 99.99% applied to non life-threatening situations, one should not worry as much about.
On the evolutionary/animal level, panic (aka fight or flight) is an excellent mechanism to stay alive...
If it had "disappeared in humans a long time ago" then that still implies a time when it existed. And if it could have existed, it could exist now.
Well, that's unfortunate because his definition happens to be the right one.
Also keep in mind some believe that a lot of "animalyness" is also "plantyness".
http://www.bbc.com/earth/story/20170109-plants-can-see-hear-...
https://www.goodreads.com/book/show/28256439-the-hidden-life...
Plants and fungi have some very complex interactive networks capable of various forms of individual, inter-individual, and inter-species communication and intelligent decision making. From our perspective though, these interactions and decisions play out over some very different time scales from our own cognition. Suppose for a second that a tree was intelligent enough to be sentient, it would be VERY difficult for either the tree or us to recognize the intelligence and cognition in the other.
"Panic" responses, fear, and the whole manner of physiologic changes that happen in a human didn't spring up over-night. These pathways evolved a VERY long time ago. An insect has some obvious "panic" type of responses to predation attempts that are not so different from our own. As you climb up the ladder in intelligence to mammals, and then all the way to humans, there is absolutely no clear line where "panic" suddenly exists as I believe you would define it. It's a very smooth and gradual transition. Even in a human, if you've ever watched one come back to consciousness after a seizure or wake up from anesthesia, you'll see that it's also a very smooth and gradual transition to what we'd call consciousness and sentience. It's not at all an on/off switch.
I wouldn't be at all surprised if some of the same neurotransmitters and hormones fill the same role in a plant response to dangerous conditions as they would humans. I know many of the same signalling molecules are in use. Evolution doesn't like to fix what ain't broke.
Oh! They've done nothing! No tribes nor social exchanges - never even mention hospitals and lasers and money and law...
No, trees are not sentient, intelligent nor exhibiting cognition.
But its all consistent with vegetable blind optimization for their environment.
As for social organization, works, cooperation - the fact that they grow in a group and are impressively big says nothing about their sentience.
"In soils across the world, fungi trade resources with the plants they colonise in a mutually beneficial relationship. But it turns out the fungi are savvy traders, taking advantage of their partners by shuttling goods to nutrient-starved areas where plants are willing to pay more than usual"
(from https://www.newscientist.com/article/2205604-brainless-fungi...)
FYI. Sort of relevant.
Sounds almost like intentionality (sentience) there.
Plants sure aren't all sweetness and light. I did suggest that, while sentience leads to inventions, it also leads to (non-feeding) murder, war (largely restricted to humans), and possibly extinction. If we 'have' any advantages on plants, sentience may not be it.
Plants can't move, and can't speak. That may explain why they've been around for oh, 50 times longer than us. And will almost certainly be around LONG after we're not. Smart?
> Sounds almost like intentionality (sentience) there
Hmm. Clarification needed - does the concept of deceit mean the deceiver understands what it is doing ie. has theory of mind? If so, I'd guess plants do not deceive but do something similar driven by evolution[0] that we need a different word for as it's not sentience-driven.
I'm open to the idea of evolution itself has some sentience but I'd not waste time on it as I don't see it's a testable hypothesis.
> If we 'have' any advantages on plants, sentience may not be it.
Agreed, but sentience may actually be an advantage. After all it's not the sentience in mankind that genuinely makes me despair but other features such as greed and short-termism. Fix those and maybe our chances of racial survival would be hugely increased. IOW we have many mental aspects and sentience is only one of them.
> around for oh, 50 times longer than us
Plants separated from aninmls ~1.7 billion years ago (figure from memory), humans have been around a few hundred thousand years, by various definitions of 'human'. I guess you dropped a few zeros :)
[0] eg. natural variegation in plants (https://en.wikipedia.org/wiki/Variegation) seems to make insects attack them less as discoloration makes the plants look to the insects less healthy (https://en.wikipedia.org/wiki/Variegation#Defensive_masquera...).
"Learning by Association in Plants"
extract of abstract: "the possibility that plants are also able to acquire learned associations to guide their foraging behaviour has never been demonstrated. Here we show that this type of learning occurs in the garden pea, Pisum sativum. By using a Y-maze task, we show that the position of a neutral cue, predicting the location of a light source, affected the direction of plant growth. This learned behaviour prevailed over innate phototropism"
https://www.nature.com/articles/srep38427
Incredible, if validated.
The word "panic" is in quotes, as a simplification of "invoke a defensive and protective reaction", and to get non-scientists to read a science article... not a terrible thing.
Edit: the original article does not quote "panic", but Professor Harvey Millar uses the word, so not clickbait?
There are different words that could have been used, like "alarm" for instance. But to leave it at "reaction" would be leaving out important details of the story that could otherwise be conveyed in a single word better than just "to react".
Another justification is that when it's sunny water droplets on leaves act as lenses and might burn the leaves.
It is also known that wet leaves increase the chance of fungi, mildew, etc. taking hold on them. The article shows that plants are also well aware of that!
The substance that makes chilis spicy is a natural anti fungal.
The article says it's no surprise plants panic because water spreads disease, which is exactly what we're avoiding by not watering the leaves. It's not to save our plants' feelings, although the root cause of the feelings and the problem we're avoiding might be the same.
While I'm sure that fogs are essential for redwoods in the California climate, it doesn't mean they are inherently coupled - they grow quite happily in the inland Canterbury Plains, bugger all fog, but enough rain to get them watered.
Hell, we even named a suburb after one: https://en.wikipedia.org/wiki/Redwood,_Christchurch
dependent on fog in certain locales.
I think it's not a particularly wild assumption that a lot of plants will react in this way. The MYC2 protein and jasmonic acid are important regulators of plant defenses so priming of defenses when it rains makes sense. There are pathogens (such as Pseudomonas syringae) that can trick a plant into opening its stomate, which are airholes on the leaves, as a means of gaining access to the interior of the leaf.
As the paper describes how the mechanical action of rain can wash pathogens around the leaf or onto other plants I think it's reasonable to think other plants would react like this.
The interplay between the jasmonic acid pathway and other plant hormone pathways is super interesting as plants, in general, have two ways of defending themselves. For pathogens that feed on dead tissue the name of the game is to keep the cells alive (jasmonic acid can be thought of as generally responsible for this sort of response), whereas for pathogens that feed on live tissue then the plant will kill of cells local to the infection site in order to deny the pathogen food (salicylic acid is largely responsible here).
"The plants used in this study are Arabidopsis thaliana" was this information in the story and I just missed it? Or are you making that assumption due to that being a "very commonly used model organism in plant biology"? The plant image used at the top of the article looks nothing like rock cres but instead more like some sort of hosta or lilly pad, I wonder if the image plant is shaped that way to catch and funnel water away from its roots? Just as a palm does the opposite? Anyways I could go on, just wish they had included the species in the article.
The picture is certainly misleading, I guess they just grabbed a generic "plants in a rainforest" picture for evocative reasons.
Would this be "that smell" that sometimes lingers after rain fall?