(bright orchestral music)
- Hey there and welcome to Brain Stuff.
I'm Josh Clark and this is the Brain Stuff
where I explain to you
whether or not plants are conscious,
which is a pretty cool question.
Have you ever seen that old
classic Star Trek episode
A Wink of an Eye, where
the Enterprise crew
encounters this race of
aliens that moves so fast
that by comparison, the Enterprise crew
seems to not move at all?
They're kind of like
plants to these aliens
and, just like in our reality,
if you look at a plant in
fast motion, you can see
that it has a lot of lively movements.
But are they really conscious?
That is a great question
and, it was first posed by
a guy named Charles Darwin,
who you may have heard
of, at some point in time.
He came up with the
concept of the root brain.
The idea behind this is that the tips
of a plant's roots act as
kind of a brain for it,
accepting information from outside stimuli
and telling the plant to act,
or move or do something as a reaction.
Over time, this concept led
to the field of what's called
Plant Neurobiology, and that term
drives other scientists crazy.
But T-S, because this field
of inquiry has yielded
some pretty cool ideas about plants.
For example, we know that
plants have a lot of senses
that are analogous to human senses
like sight, smells, sound, touch, taste.
Like when a plant senses
that a caterpillar
is eating one of its
leaves, it will produce
this kind of substance
that's like a mustard oil
that repelsthe caterpillar.
The cool thing is that
scientists have found
when they play just the audio
recording of a caterpillar,
there's no caterpillar anywhere around,
by a plant, the plant
will still produce this
mustard oil like substance,
which means that plants can hear in a way.
That's pretty awesome, right?
This chemical signaling
thing appears in plants
throughout nature.
The smell of fresh cut
grass is actually a signal
to other grass plants
that there is some sort
of crazy danger afoot.
What's going on?
I don't know but everybody duck.
Now the reason some
scientists hate the term
Plant Neurobiology is that
plants lack neurons, hence,
they can't have a neurobiology.
But this is kind of splitting hairs.
Researchers have found that
plants do have something
that's like a central nervous system.
They have glutamate receptors,
just like we do.
We use ours to form memories.
They have neurotransmitters
and they use electricity
to transfer information
throughout the plant,
to get it to move and react.
And, some scientists have found
that when you give plants drugs,
yes, some scientists give plants drugs,
that it can actually have weird effects
on the plant's central nervous system.
Like, they're on drugs.
Plants can also display learning behavior,
which is another hallmark
of consciousness.
For example, the Mimosa
pudika plant has this
cool defense mechanism
where when it senses danger,
it curls its leaves inward.
But, that requires a lot of energy,
so the Mimosa pudica plant has evolved
to not curl its leaves
when it deems the stimulis
non dangerous.
Alright?
Well, scientists found
that when they dropped
the Mimosa pudica plant, at
first, it'll curl its leaves,
but after a few drops, it'll figure out
that the drop is not actually a threat,
and will learn to stop curling its leaves.
Even more astounding, is
that these plants display
some sort of memory,
because a month later,
when they're dropped again,
they still won't curl their leaves.
It's not a novel experience anymore,
the plants have learned.
So are plants conscious?
The jury's still out,
but it's starting to look that way.
So maybe, when you hear
that you're supposed
to talk to your plants,
to get them to grow more,
it's not actually because
of the CO2 you're breathing
out onto them, it's
because they're reacting
to being treated nicely.
This is a great episode.
I know you agree, and,
for even more great stuff,
a universe of great stuff,
go to How Stuff Works, you'll love it.
