Rigidity control mechanism by turgor pressure in plants

Abstract

The bodies of herbaceous plants are slender, thin, and soft. These plants support their bodies through the action of turgor pressure associated with their internal water stores. The purpose of this study was to apply the principles of structural mechanics to clarify the underlying mechanism of rigidity control that is responsible for turgor pressure in plants and the reason behind the self-supporting ability of herbaceous plants. We modeled a plant a horizontally oriented thin-walled cylindrical cantilever with closed ends enclosing a cavity filled with water that is acted on by its own weight and by internal tension generated through turgor pressure. We derived an equation describing the plant’s consequent deflection, introducing a dimensionless parameter to express the decrease in deflection associated with the action of turgor pressure. We found that the mechanical and physical characteristics of herbaceous plants that would appear to be counter-productive from a superficial perspective increase the deflection decreasing effect of turgor pressure.

Mechanics-based classification rule for plants

“…We also considered the mechanical and geometrical properties of woody and herbaceous plants. Most woody plants have solid, heavy, thick, and large bodies ( 5 , 6 , 8 , 25 , 26 , 39 ). These characteristics reduce the tension parameter .…”

Turgor pressure affects transverse stiffness and resonant frequencies of buzz-pollinated poricidal anthers

“…Consistent with previous modeling efforts, we assumed that the influence of turgor pressure on the beam-like anther could be idealized as an axial tensile load [34]. The magnitude of the tensile load was proportional to the turgor pressure and anther cross sectional area.…”

“…Methods have been developed to measure the turgor pressure on the organ scale, such as the pressure bomb [32], as well as on the tissue or cellular scale, such as pressure probe or indentation techniques [33]. It is well established that turgor pressure affects the rigidity of plant structures; reductions in turgor pressure are associated with wilting [34]. Several factors influence the turgor pressure within plant tissues, including water availability, temperature, and soil conditions [35, 36, 37].…”