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Plants are able to remember information and react to it, thanks to an
internal communications system that can be likened to a central nervous
system in animals, according to a new study by a Polish plant biologist.
Plants "remember" information about light, and a certain type of cell
transmits that information, much like nerves do in animals.
In the study, which was published in the early online version of the
journal Plant Cell July 16, the researchers found that light shone on
one leaf of an Arabidopsis thaliana plant caused the whole plant to
respond. The response lasted even after the light source was taken away,
suggesting the plant remembered the light input.
"The signaling continiues after the light is off; it is building short-
term memory," said the lead author, Stanislaw Karpinski, in an e-mail
message. "The leaves are able to physiologically 'memorize' different
excess light episodes and use this stored information, for example, for
improving their acclimation and immune defenses."
The leaves remember light quality as well as quantity, Karpinski added -
- different wavelengths of light produce a different response,
suggesting the plants use the information to generate protective
chemical reactions like pathogen defense or food production.
As reported by the BBC July 14, scientists found that light shining on a
leaf cell triggered a cascade of events that was immediately signaled to
the rest of the plant via a type of cell called a bundle sheath cell.
Those cells exist in every part of a plant. Karpinski, of the Warsaw
University of Life Sciences in Poland, measured the electrical signals
from those cells, and compared it to finding a central nervous system
for plants.
Terence Murphy, a plant biology professor at the University of
California-Davis who was not involved in the research, said shining
light on that first leaf could have any number of effects.
"The leaf would be loaded up with starch, maybe; that's going to have a
real effect on how it communicates through the phloem (vascular system)
to other leaves. It's not unreasonable that you could illuminate one
leaf and affect the other leaves," he said.
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TAGS
Science, Rebecca Boyle, agriculture, Arabidopsis, environment, memory,
Nervous System, plant biologist, plants The trick is finding out how the
other leaves are informed -- and that's what appears to have been done
in the Polish study. Bundle sheath cells surround the veins in leaves,
stems and roots, so it's reasonable to think they transmit the
electrical impulse, Murphy said.
Biologists have long known that plants can remember -- they need to know
whether they've gone through a cold season before they can germinate in
the spring, for instance. It's not memory as we know it, but a prolonged
change in plant internal systems that causes effects later.
What's more, scientists already know plants transmit electrical signals
in response to a stimulus, just as nerves do. This is easily measured
using a basic electrode setup, according to Murphy.
Karpinski said the light memory represents a new way for plants to
respond to pathogens or disease -- normally, they respond by direct
contact with an invader.
"This information would not be a revelation untill we find that plant
leaves can remember it for several days and process this memorized
information to (bolster) their defense mechanisms against seasonal
diseases," he wrote.
Karpinski is well-known among plant biologists for earlier work on how
plants respond to light stress. In a previous study, he also showed
chemical signals can be passed throughout whole plants, allowing them to
respond to and survive environmental changes. Understanding the
mechanisms that cause those signals is a new step, however.
William John Lucas, distinguished professor of plant biology at UC-Davis
and chair of the plant biology department, said an internal
communication system would provide a wealth of information to different
parts of the plant.
"A particular tissue within a plant needs to be able to signal to the
rest of the plant in terms of what are its conditions, what should you
expect," he said. "If a young leaf is emerging out of a plant, it would
be nice for that leaf to know about the conditions in which it is going
to emerge."
Lucas studies how plants pick up non-biological information, such as
water and light, and how they transmit that information so the entire
plant knows under which constraints it will grow. Plants can't move to a
sunnier, wetter spot, so they need to make the most of their
environment.
Tapping into their "nervous system" would help scientists understand how
they do that, Lucas said. That knowledge could lead to optimized food
crops or hardier trees.
"There are no neurons in plants, but there is a communication network
that we don't fully understand," he said. "There are important
implications for these kinds of studies."
http://www.popsci.com/science/article/2010-07/study-unveils-plant-
nervous-system-illuminating-how-plants-remember-and-react
internal communications system that can be likened to a central nervous
system in animals, according to a new study by a Polish plant biologist.
Plants "remember" information about light, and a certain type of cell
transmits that information, much like nerves do in animals.
In the study, which was published in the early online version of the
journal Plant Cell July 16, the researchers found that light shone on
one leaf of an Arabidopsis thaliana plant caused the whole plant to
respond. The response lasted even after the light source was taken away,
suggesting the plant remembered the light input.
"The signaling continiues after the light is off; it is building short-
term memory," said the lead author, Stanislaw Karpinski, in an e-mail
message. "The leaves are able to physiologically 'memorize' different
excess light episodes and use this stored information, for example, for
improving their acclimation and immune defenses."
The leaves remember light quality as well as quantity, Karpinski added -
- different wavelengths of light produce a different response,
suggesting the plants use the information to generate protective
chemical reactions like pathogen defense or food production.
As reported by the BBC July 14, scientists found that light shining on a
leaf cell triggered a cascade of events that was immediately signaled to
the rest of the plant via a type of cell called a bundle sheath cell.
Those cells exist in every part of a plant. Karpinski, of the Warsaw
University of Life Sciences in Poland, measured the electrical signals
from those cells, and compared it to finding a central nervous system
for plants.
Terence Murphy, a plant biology professor at the University of
California-Davis who was not involved in the research, said shining
light on that first leaf could have any number of effects.
"The leaf would be loaded up with starch, maybe; that's going to have a
real effect on how it communicates through the phloem (vascular system)
to other leaves. It's not unreasonable that you could illuminate one
leaf and affect the other leaves," he said.
RELATED ARTICLES
Video: Scientists Watch Grass Grow, at the Cellular Scale
Strawberries May Be Ideal Crop for Space Farms of the Future
The First Artificial Nerve Cell That Uses Real Neurotransmitters
TAGS
Science, Rebecca Boyle, agriculture, Arabidopsis, environment, memory,
Nervous System, plant biologist, plants The trick is finding out how the
other leaves are informed -- and that's what appears to have been done
in the Polish study. Bundle sheath cells surround the veins in leaves,
stems and roots, so it's reasonable to think they transmit the
electrical impulse, Murphy said.
Biologists have long known that plants can remember -- they need to know
whether they've gone through a cold season before they can germinate in
the spring, for instance. It's not memory as we know it, but a prolonged
change in plant internal systems that causes effects later.
What's more, scientists already know plants transmit electrical signals
in response to a stimulus, just as nerves do. This is easily measured
using a basic electrode setup, according to Murphy.
Karpinski said the light memory represents a new way for plants to
respond to pathogens or disease -- normally, they respond by direct
contact with an invader.
"This information would not be a revelation untill we find that plant
leaves can remember it for several days and process this memorized
information to (bolster) their defense mechanisms against seasonal
diseases," he wrote.
Karpinski is well-known among plant biologists for earlier work on how
plants respond to light stress. In a previous study, he also showed
chemical signals can be passed throughout whole plants, allowing them to
respond to and survive environmental changes. Understanding the
mechanisms that cause those signals is a new step, however.
William John Lucas, distinguished professor of plant biology at UC-Davis
and chair of the plant biology department, said an internal
communication system would provide a wealth of information to different
parts of the plant.
"A particular tissue within a plant needs to be able to signal to the
rest of the plant in terms of what are its conditions, what should you
expect," he said. "If a young leaf is emerging out of a plant, it would
be nice for that leaf to know about the conditions in which it is going
to emerge."
Lucas studies how plants pick up non-biological information, such as
water and light, and how they transmit that information so the entire
plant knows under which constraints it will grow. Plants can't move to a
sunnier, wetter spot, so they need to make the most of their
environment.
Tapping into their "nervous system" would help scientists understand how
they do that, Lucas said. That knowledge could lead to optimized food
crops or hardier trees.
"There are no neurons in plants, but there is a communication network
that we don't fully understand," he said. "There are important
implications for these kinds of studies."
http://www.popsci.com/science/article/2010-07/study-unveils-plant-
nervous-system-illuminating-how-plants-remember-and-react
