Saturday, July 17, 2010

plants can "think and remember"

BBCNews | 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.

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 by via 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".