Flower power

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The ticklish, often-tragic business of landmine detection might soon be taken over by a civilian armed with nothing more than a spray gun. A plant altered to show civilians the location of planted landmines might do the work instead. The project is one more proof of the power and utility of genetically modified plants, and the need for such seedlings of promise to be passed to the nations that need them most.

The weed is a strain of watercress known as Thale cress, which grows quickly, is self-pollinating and thrives in many climes. It was transformed by a group of researchers at the University of Copenhagen to turn red in the presence of landmines. It actually detects the gas nitrogen dioxide, which leaks from many types of mines. After about three weeks of exposure to the gas, the gene that naturally causes the plant to change color in the fall makes it grow red. Researchers also removed a gene for a growth hormone the plant needs to prevent it from spreading in the wild. It should only grow after a specially made fertilizer has been applied.

The plant is likely to see a great deal of action. About 100 million landmines are believed to have been buried in approximately 45 countries. Fear of such fields has made huge swaths of arable land in poor nations unusable. Landmines kill or wound approximately 26,000 people each year. Aside from accidents, they can only be detected by humans or specially trained dogs.

Not all buried explosives will be found by the plant. Some mines do not leak nitrogen dioxide, while others are buried too deep for it to sense. False positives could also be a problem. The plants were designed with such sensitivity that scattered cartridges might be sufficient to cause the color change. Extensive field testing, which is starting this spring, will be the only way to know for certain.

That testing should go forward. Anti-genetically modified foods activists claim that existing political means are sufficient to solve the problem of landmines. However, the utility of landmines makes them likely to be a constant hazard on future battlefields. Even a global ban on their manufacture or use would do nothing to clear existing fields.

In his poem "Grass," Carl Sandburg wrote about the grass that covers the scars of bloody battlefields. In the future, genetically modified plants might do the opposite, allowing farmers to safely till soil where deathtraps were once sown. Whenever possible, policy-makers should encourage the development and use of such flower power.