Rellán-Álvarez, R. et al. eLife doi:10.7554/eLife.07597 (2015).

A plant's root architecture determines its access to water and nutrients in the soil. However, most roots are studied in the light on artificial media, and much remains unknown about how soil-embedded roots grow and change in response to environmental cues. Rellán-Álvarez et al. have developed a new imaging platform called Growth and Luminescence Observatory for Roots (GLO-Roots). In GLO-Roots, Arabidopsis plants expressing one or more luciferases are grown and imaged in soil in thin chambers in the dark. Prior to imaging, luciferin is added to the plants during watering to generate a bioluminescent signal that is recorded with a custom imaging system. The team also developed algorithms for analyzing root data that can be implemented in ImageJ. GLO-Roots enabled the authors to track root growth under different conditions and make quantitative comparisons of root growth in different Arabidopsis strains.