The stress-strain relation of the plasma membrane of isolated plant protoplasts

Over periods of up to a few seconds the plasma membrane of isolated rye protoplasts behaves elastically with an area modulus of $\text{230}\text{mN}\text{·}\text{m}{}^{\mathrm{?1}}$. Over longer periods, the area increases with time under large tension and decreases under sufficiently small tension, suggesting that material is incorporated into or depleted from the plane of the membrane.