Bright, Green Potatoes
The fluorescence, produced by a jellyfish protein, is activated in the plant by the production of abscisic acid, which signals the plant to rearrange its cells during an anticipated water shortage.
Professor Tony Trewavas from the University of Edinburgh, aware of some people's concern about GM crops, told BBC News Online: "People are worried, but these potatoes will never enter the food chain. They are sentinels and would be put in separately and harvested separately."
Speaking at the British Association's Festival of Science in Sheffield, UK, Trewavas said that just sowing eight plants per hectare would allow a farmer to monitor the whole field.
The potatoes will not glow to the human eye, however. The light is produced by absorbing a narrow wavelength of blue light, which is re-emitted as yellow.
A small detector, built by the Scottish Agricultural College, spots the yellow light and sets off a green signal that says "water me." If no signal is showing, then the plants have enough water.
"The problem at the moment is that farmers don't know how much water is needed—they just pour it on," said Professor Trewavas.
"We believe our system would save farmers about £270 per hectare in terms of reduced water use and reduced fertilizer applied. You don't have to put as much nitrate on if you don't over-water and run off lots of your minerals."
Experiments so far have been confined to greenhouses, and it will be about six years before the glowing potatoes go on sale.
Future plans are to include slightly different fluorescent proteins that will report on the plants' nitrate, phosphate, and sucrose status.
For more information: Tony Trewavas, Institute of Cell and Molecular Biology, The University of Edinburgh Centre, 7 - 11 Nicolson Street, Edinburgh, Scotland EH8 9BE. Tel: +44 131 650 1000. Email: trewavas@srv0.bio.ed.ac.uk.