Science: Plants 'Can Think and Remember'

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 ... 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.

"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".

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

For more, see Plants 'Can Think and Remember' by Victoria Gill, July 14, 2010, at BBC.