Lateral roots emerge from the primary root at right angles but briefly grow asymmetrically to set a distinct growth angle. Here Waidmann et al. show that cytokinin acts as an anti-gravitropic signal that impairs growth on the upper side of emerged lateral roots to promote radial expansion of the root system.
- Sascha Waidmann
- Michel Ruiz Rosquete
- Jürgen Kleine-Vehn