Cell wall elastic properties of <i>Chara corallina</i>

Abstract

Transcellular osmosis measurements are combined with measurements of the kinetics of relative length change, when Chara corallina cells are transferred from artificial pond water to polyethylene glycol (mol wt 300 to 400) of higher osmotic pressure to yield the constant k, which relates relative volume change ΔV/V to relative length change Δl/l (ΔV/V = k Δl/l). The value of k is 3.5 and is temperature independent between 7 and 30 °C. Static and kinetic estimates of the bulk modulus, ε, indicate that ε is temperature independent and has a value between 500 to 650 bars at high turgor pressures. The value of ε declines as the turgor pressure declines. We show how ε and k are related to Young's modulus and to Poisson's ratio for anisotropic C. corallina cell walls and point out that the previous treatments of the problem are in error.