Stomatal development: cross talk puts mouths in place.

Stomata are crucial for the productivity and survival of land plants. Until recently, little was known about the events and molecular pathways required for stomatal development. Emerging data indicate that cell-cell signaling conveys spatial information about cell identity and location. Such information might pattern stomata by orienting the plane of asymmetric division and might control stomatal number by regulating division frequency. This pathway also provides an accessible model system for studying post-apical meristem stem cells that generate specific tissues.