One day we will know for sure that all the trees we killed and the
grass we pulled out, all the plants we mutilate and the flowers we
arrange in vases – all of them have the same senses and intelligence as
us. They are not inanimate, passive species, but highly evolved beings.
In
India we have people who have reached a point where they have become
one with themselves and nature. All our gurus of every religion have
talked about non-dual awareness - no me and you, just one, being the key
to the liberated vision that is the true meaning of happiness.
Dr
Monica Gagliano of the University of Sydney has written an amazing book”
Thus Spoke the Plant” (North Atlantic Books). She has taken the
difficult path of showing, through scientific experimentation, the
different senses of the plant. I am going to write about two of her
experiments.
There is an elementary type of learning called
“habituation,” in which a subject is taught to focus on important
information, while filtering out irrelevant rubbish. How long does it
take the animal to recognize that a stimulus is “rubbish,” and how long
will it remember what it has learned? Gagliano wanted to know whether
the same thing can be done by a plant. Mimosa pudica, the Sensitive
Plant, is that rare plant with a behaviour both speedy and visible. As
children you have played at touching its fernlike leaves (chooee mooee)
to watch them fold up immediately. This is probably a defence mechanism,
or to frighten insects into staying away. The mimosa also collapses
its leaves when the plant is dropped or jostled. Gagliano potted
fifty-six mimosa plants and made a system to drop them from a height of
fifteen centimetres every five seconds. Each “session” involved sixty
drops. In the beginning each mimosa plant folded its leaves as soon as
they were dropped. But some of the mimosas started to reopen their
leaves after just four, five, or six drops, as if they had concluded
that nothing bad was going to happen and they could ignore the
happening. By the end, all of them were completely open, no matter how
many times they were dropped. Was this just fatigue? Apparently not:
when the plants were shaken, they again closed up. The plant had attuned
itself to a new stimulus. Gagliano retested her plants after a week
and found that they continued to disregard the drop stimulus, indicating
that they “remembered” what they had learned. Even after twenty-eight
days, the lesson had not been forgotten.
Humans insist that
intelligence comes from an identifiable “brain”, a command centre . It
could well be cells exchanging intelligent signals in a network. Memory
is part of intelligence – and yet we know so little about how it works.
We think that animal memory involves the laying down of new pathways in a
network of neurons. But there are ways to store information that don’t
require neurons. Immune cells “remember” their experience of pathogens,
and call on that memory in subsequent encounters. In plants, it is known
that experiences such as stress can alter the molecular wrapping around
the chromosomes, and this determines which genes will be silenced.
Scientists now know that events, like traumas and starvation, change
animal brains and can be passed on to offspring. This is what happens in
plants as well.
In another experiment Gagiliano places a parasitic
vine, Cuscuta europaea, near potential host plants. This white vine
coils itself around the stalk of another plant and sucks nourishment
from it. The vine always chooses, assessing by scent, the host which
offers the best potential nourishment. Having selected a target, the
vine then performs a cost-benefit calculation before deciding exactly
how many coils it should invest—the more nutrients in the victim, the
more coils it deploys.
The book is full of such experiments. But it
is more than just scientific. Gagliano invites us to see the world at a
far more profound level, than the one that we are accustomed to. We have
a constructed a simplistic narrative of plants lacking in intelligence
or sentience. This version ignores their evolutionary history. It is
only human arrogance that keeps us from appreciating their intelligence
and success. Plants dominate every terrestrial environment, composing
ninety-nine per cent of the biomass on earth. In comparison, humans and
all animals are just traces.
Many years ago, Dr Ashok Khosla (the
head of Club of Rome – one of the best recognised collection of
scientific minds) of Development Alternatives, and I visited a place in
Italy called Damanhur headed by a seer called Falco. It is a place where
the best minds go and it is humming with experiments on how to live.
One of the things we saw was a small machine that, when attached to a
plant, brings its voice down to human hearing levels. Meaning : you can
hear it speak. Not in any way that humans can understand, but it
certainly converses with another plant attached to a machine too. It is a
conversation: one speaks, then the other. Another species of plant has a
different language, but in time learns the first.
“The Secret Life
of Plants,” by Peter Tompkins and Christopher Bird, described the
experiments of a C.I.A. polygraph expert named Cleve Backster, who, in
1966, hooked up the galvanometer to the leaf of a dracaena plant.
Backster found that by simply imagining the dracaena on fire he could
make the needle of the polygraph machine go up and down, registering a
surge of electrical activity that in human beings meant stress. “Could
the plant have been reading his mind?” the authors ask. “Can plants
think?”
Backster and his collaborators went on to hook up polygraph
machines to dozens of plants, including lettuces, onions, oranges, and
bananas. They found that plants reacted to the thoughts of humans in
close proximity and, in the case of humans familiar to them, over a
great distance. In one memory experiment , Backster found that a plant
that had witnessed the murder (by stomping) of another plant could pick
out the killer from a lineup of six suspects, registering a surge of
electrical activity when the murderer was brought before it. Backster’s
plants also displayed a strong aversion to interspecies violence. Some
had a stressful response when an egg was cracked in their presence, or
when live shrimp were dropped into boiling water, an experiment that
Backster wrote up for the International Journal of Parapsychology, in
1968. They are capable of cognition, communication, information
processing, computation, learning, and memory.
Our tendency to equate
behaviour with mobility, keeps us from appreciating what plants can do.
In fact, many of the most impressive capabilities of plants can be
traced to the fact that they are unable to move when they need
something, or when conditions turn unfavourable. Imagine defending
yourself and finding everything you need while being fixed in one place.
Plants have evolved between fifteen and twenty distinct senses,
including variations of our five: smell and taste (they sense and
respond to chemicals in the air, or on their bodies); sight (they react
differently to various wavelengths of light, as well as to shadow);
touch (a vine, or a root, “knows” when it encounters a solid object);
and sound. In an experiment, Heidi Appel, a chemical scientist at the
University of Missouri, found that when she played a recording of a
caterpillar chomping on a leaf, for a plant that hadn’t been touched,
the sound primed the plant to produce defence chemicals. Another
experiment found that plant roots would seek out a buried pipe through
which water was flowing, even if the exterior of the pipe was dry, which
suggests that the plants could “hear” the sound of flowing water.
Unable
to run away, plants deploy a complex vocabulary to signal distress,
deter or poison enemies, and recruit animals to perform various services
for them. A study in Science found that the caffeine produced by plants
functions not only to keep away certain insects but as an addictive
drug in their nectar, which keeps bringing the same bees back, making
them faithful and effective pollinators.
We now know that when a
plant’s leaves are infected, or chewed, by insects they emit chemicals
that signal other leaves to mount a defence. This warning signal
contains information about the identity of the insect. The defence
involves altering the leaf’s flavour or texture, or producing toxins
that render the plant’s flesh less digestible. When antelopes browse
acacia trees, the trees let them. When the eating increases, the leaves
produce tannins that make them unappetizing. When food is scarce and
acacias are over-browsed, the trees produce sufficient amounts of toxins
to kill the animals.
Plants signal insects as well. Corn and lima
beans emit a chemical distress call when attacked by caterpillars.
Parasitic wasps, some distance away, follow the scent to the afflicted
plant and destroy the caterpillars.
Two years ago the Bill and
Melinda Gates Foundation sponsored a think tank on plant communication
in Seattle, and thirty leading scientists attended it. Open your senses.
Change your view of the world and what you do with it. If you realised
that your table was a magnificent talking, thinking being, you would not
be in such a hurry to get wooden furniture into your house, use paper,
toothpicks, or make your offerings with agarbatti sticks.
Maneka Sanjay Gandhi