The dynamics of root meristem distribution in the soil.

Plants must develop efficient root architectures to secure access to nutrients and water in soil. This is achieved during plant development through a series of expansion and branching processes, mostly in the proximity of root apical meristems, where the plant senses the environment and explores immediate regions of the soil. We have developed a new approach to study the dynamics of root meristem distribution in soil, using the relationship between the increase in root length density and the root meristem density. Initiated at the seed, the location of root meristems in barley seedlings was shown to propagate, wave-like, through the soil, leaving behind a permanent network of roots for the plant to acquire water and nutrients. Data from observations on barley roots were used to construct mathematical models to describe the density of root meristems in space. These models suggested that the morphology of the waves of meristems was a function of specific root developmental processes. The waves of meristems observed in root systems of barley seedlings exploring the soil might represent a more general and fundamental aspect of plant rooting strategies for securing soil resources.