DEPENDENCY OF THE TENSILE MODULUS ON TRANSVERSE DIMENSIONS, WATER POTENTIAL, AND CELL NUMBER OF PITH PARENCHYMA

Publisher Website
Google Scholar
Abstract
Uniaxial tensile tests of solid and hollow cylindrical plugs of pith parenchyma from potato tubers indicate the tensile modulus of elasticity, E, can vary significantly as a function of tissue transverse area and water potential. E increases from 1.2 to 19 MPa as ψw changes from ‐1.4 to ‐0.4 MPa. E increases from 5 to 19 MPa as transverse area of solid tissue sample increases from 0.2 to 2.5 cm2. Variations in E accompanying changes in transverse area appear to be related to cell number along the radii of plugs. Hollow cylindrical plugs for which wall thickness is maintained but total tissue area is changed show constant values of E. It is suggested that shear stresses within tissue samples influence E and are dependent upon cell number and tissue water content. Material with these properties would be a “poor choice” for constructing plant organs experiencing repeated stress and periodic dehydration. However, ground tissue may act as a buffer against localized ovaling of stem and leaf cross sections under loading.
Funding Information
  • National Science Foundation (BSR‐8320272)