Flower power

Ingenious (hat tip: Daniel Drezner):

A Danish company, Aresa Biodetection, has developed genetically-modified flowers that change color when their roots come in contact with nitrogen dioxide in the soil. Explosives used in mines produce NO2 as the chemicals gradually decay. The company plans to sow fields of NO2-sniffing Arabidopsis thaliana (Thale or mouse cress) in areas riddled with long-forgotten ordinance from Angola to Cambodia.