Morphomechanics of Plants

Abstract

Plants operate with tensional and compressive stresses that are extreme by animal standards. These stresses vary sharply on sub-and supracellular scales, but are orchestrated at the organismal level and evolve in a well-defined way during morphogenetic events. Plant morphogenesis is accomplished by localized and anisotropic yielding of cell walls that accommodate turgor-driven extension without losing mechanical integrity. Plant cell walls are connected cohesively into a stressallocating network enabling mechanical forces to be efficiently transmitted and serve as a long-distance messenger that plays an important integrative and regulatory role. Mechanical forces control the dynamics of both cortical microtubules and phytohormone auxin transporters, the two key players in guiding plant morphogenesis. The onset of organogenetic events in shoots and roots is associated with stereotypical changes in the pattern of tissue stresses. Initiation of leaves, lateral roots, and root hairs can be rationalized within the framework of the concept of stress hyperrestoration.