Plants use distributed computation to decide how to open and close their stomata in order to take in as much CO2 as possible while losing the least amount of water.
Research by David Peak, West, J. D., Messinger, S. M and Mott, K. A at Utah State University in Logan.
“Leaves have openings called stomata that open wide to let CO2 in, but close up to prevent precious water vapour from escaping. Plants attempt to regulate their stomata to take in as much CO2 as possible while losing the least amount of water. But they are limited in how well they can do this: leaves are often divided into patches where the stomata are either open or closed, which reduces the efficiency of CO2 uptake.
By studying the distributions of these patches of open and closed stomata in leaves of the cocklebur plant, Peak and colleagues found specific patterns reminiscent of distributed computing. Patches of open or closed stomata sometimes move around a leaf at constant speed, for example.
The statistics of the size of these patches, and of the waiting times between the appearance of successive patches, are the same as those for a model of cellular automata, the researchers say. The individual leaf stomata appear to act like simple computers, responding to what their neighbouring stomata are doing.
The researchers think that transient patchiness may be the price the plant pays for a reasonably efficient and simple way form of computation. It is a sign of the plant ‘thinking’ while it figures out the best solution to the problem of how much to open its stomata.
— Philip Ball. Do plants act like computers? Leaves appear to regulate their ‘breathing’ by conducting simple calculations. Nature Science Update, 21 January 2004
Peak, D. A., West, J. D., Messinger, S. M & Mott, K. A. Evidence for complex, collective dynamics and emergent, distributed computation in plants. Proceedings of the National Academy of Sciences USA, 101, 918 – 922, (2004).