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Die Vrou
7th May 2013, 07:52
Plants' 'nervous system' discovered

Last Updated: Thursday, July 15, 2010, 18:31

Tags: plant, nervous system

Plants` `nervous system` discovered London: Plants "remember" and "react" to information encrypted in light as well as transmit information about light intensity and quality from leaf to leaf, a process that is strikingly similar to the human nervous system.

These "electro-chemical signals" are carried by cells, which act as plant "nerves".

Led by Professor Stanislaw Karpinski, from the Warsaw University of Life Sciences in Poland, researchers used fluorescence imaging to observe the plants'' response.

The research team found that light shone on to one leaf generated a response from the whole plant.

The response, which took the form of light-induced chemical reactions in the leaves, continued in the dark.

This demonstrated, said scientists, that the plant "remembered" the information encoded in light.

"We shone the light only on the bottom of the plant and we observed changes in the upper part," The BBC quoted Prof Karpinski, as saying.

"And the changes proceeded when the light was off... This was a complete surprise," he added.

Prof Karpinski and his team found that when light triggered a chemical reaction in one leaf cell, it kicked off a "cascade" of events and that this was immediately signalled to the rest of the plant via a specific type of cell called "bundle sheath cell".

The researchers were even more intrigued when the plants'' responses changed depending on the colour of the light that was being shone on them.

Prof Karpinski said: "There were characteristic [changes] for red, blue and white light."

Prof Karpinski felt plants might use the information encoded in the light to stimulate protective chemical reactions. He and his team analysed this more closely by investigating the effect of different colours of light on the plants'' immunity to disease.

Prof Karpinski said: "When we shone the light for on the plant for one hour and then infected it [with a virus or with bacteria] 24 hours after that light exposure, it resisted the infection."

"But when we infected the plant before shining the light, it could not build up resistance.

"[So the plant] has a specific memory for the light which builds its immunity against pathogens, and it can adjust to varying light conditions."

He also said plants used information contained in the light to immunise themselves against seasonal pathogens.

Prof Karpinski explained: "Every day or week of the season has... a characteristic light quality.

"So the plants perform a sort of biological light computation, using information contained in the light to immunise themselves against diseases that are prevalent during that season."

Prof Karpinski presented the findings at the Society for Experimental Biology''s annual meeting in Prague, Czech Republic.

(ANI)

Die Vrou
7th May 2013, 07:54
Plants 'can think and remember'
By Victoria Gill Science reporter, BBC News
Arabidopsis (Image: SPL) The scientists discovered the "nervous systems" of Arabidopsis plants
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Plants are able to "remember" and "react" to information contained in light, according to researchers.

Plants, scientists say, transmit information about light intensity and quality from leaf to leaf in a very similar way to our own nervous systems.

These "electro-chemical signals" are carried by cells that act as "nerves" of the plants.
Fluorescence image of Arabidopsis plant The researchers used fluorescence imaging to watch the plants respond

In their experiment, the scientists showed that light shone on to one leaf caused the whole plant to respond.

And the response, which took the form of light-induced chemical reactions in the leaves, continued in the dark.

This showed, they said, that the plant "remembered" the information encoded in light.

"We shone the light only on the bottom of the plant and we observed changes in the upper part," explained Professor Stanislaw Karpinski from the Warsaw University of Life Sciences in Poland, who led this research.

He presented the findings at the Society for Experimental Biology's annual meeting in Prague, Czech Republic.

"And the changes proceeded when the light was off... This was a complete surprise."

In previous work, Professor Karpinski found that chemical signals could be passed throughout whole plants - allowing them to respond to and survive changes and stresses in their environment.

But in this new study, he and his colleagues discovered that when light stimulated a chemical reaction in one leaf cell, this caused a "cascade" of events and that this was immediately signalled to the rest of the plant via a specific type of cell called a "bundle sheath cell".

The scientists measured the electrical signals from these cells, which are present in every leaf. They likened the discovery to finding the plants' "nervous system".
Thinking plants

What was even more peculiar, Professor Karpinski said, was that the plants' responses changed depending on the colour of the light that was being shone on them.
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Plants perform a sort of biological light computation, using information contained in the light to immunise themselves against diseases ”

Stanislaw Karpinski Warsaw University of Life Sciences

"There were characteristic [changes] for red, blue and white light," he explained.

He suspected that the plants might use the information encoded in the light to stimulate protective chemical reactions. He and his colleagues examined this more closely by looking at the effect of different colours of light on the plants' immunity to disease.

"When we shone the light for on the plant for one hour and then infected it [with a virus or with bacteria] 24 hours after that light exposure, it resisted the infection," he explained.

"But when we infected the plant before shining the light, it could not build up resistance.

"[So the plant] has a specific memory for the light which builds its immunity against pathogens, and it can adjust to varying light conditions."

He said that plants used information encrypted in the light to immunise themselves against seasonal pathogens.

"Every day or week of the season has… a characteristic light quality," Professor Karpinski explained.
Flourescent image of leaves The images showed chemical reactions in leaves that were not exposed to light

"So the plants perform a sort of biological light computation, using information contained in the light to immunise themselves against diseases that are prevalent during that season."

Professor Christine Foyer, a plant scientist from the University of Leeds, said the study "took our thinking one step forward".

"Plants have to survive stresses, such as drought or cold, and live through it and keep growing," she told BBC News.

"This requires an appraisal of the situation and an appropriate response - that's a form of intelligence.

"What this study has done is link two signalling pathways together... and the electrical signalling pathway is incredibly rapid, so the whole plant could respond immediately to high [levels of] light."
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