Viscoelastic properties of plant cell walls—II. Effect of pre-extension rate on stress relaxation

Abstract

The stress relaxation parameters ${\mathit{T}}_{\mathit{o}}$ , ${\mathit{T}}_{\mathit{m}}$ , b, and c vary depending upon the pre-extension rate when a cell wall specimen is stretched using a tensile tester. The effect of the pre-extension rate on the stress relaxation parameters of pea epidermal cell wall was investigated using a newly established equation. The change in the parameters due to the pre-extension rate can be corrected by the equation qualitatively and approximately quantitatively. The newly established equation appears to validly express the stress relaxation process with consideration for the pre-extension rate and the parameters ${\mathit{T}}_{\mathit{o}\mathit{k}}$ , ${\mathit{T}}_{\mathit{m}\mathit{k}}$ , ${\mathit{b}}_{\mathit{k}}$ , ${\mathit{c}}_{\mathit{k}}$ and K in the equation seem to represent the characteristic mechanical properties of the cell wall, although the parameters ${\mathit{T}}_{\mathit{o}}$ , ${\mathit{T}}_{\mathit{m}}$ , b, and c are valid for practical use to analyze the auxin effect on the mechanical properties of the cell wall.