Plant Biomechanics - A Natural Transition from Molecular to Organ Scale

Abstract

"Plants are multicellular organisms of a unique structure because their tissues consist of two interwoven networks: a network of interconnected protoplasts that is embedded in a network of tightly joined cell walls. Such a structure has significant implications from both developmental and biomechanical perspectives. First, it facilitates mechanical signaling and integration at the organ level. Second, plant tissues can be regarded as cellular solids [1]. An emerging mechanical property of such “constructed” plant organs is that they are prestressed. In the case of green plant organs, built mainly of living tissues, the cellular solids are pressurized by turgid protoplasts. Because tissues within the organ differ in cell size and cell wall stiffness, this pressurization leads to different stresses in different organ portions. Woody stems of living trees are also prestressed. Although they are built mainly of dead cells, the prestress develops during their differentiation. Such natural prestressed constructions are analogous to prestressed concrete, which revolutionized architecture, e.g., the construction of bridges. Also, in the case of plant organs, the prestress, referred to as tissue stress or tensegrity at the organ scale, improves their mechanical performance [2,3]. However, another consequence of such a plant construction is that biomechanical processes acting at subcellular, cellular, and organ scales are closely related and hard to separate, while investigations of molecular mechanisms, in which mechanical factors are involved, are by rule blended with tissue and organ level research." [...] (fragm.)