Phycomyces: Mechanical Analysis of the Living Cell Wall

Abstract

Stress relaxation measurements were conducted on stage IVb Phycomyces sporangiophores in order to correlate the effect of imposed stress on cell wall growth. It was found that the cell wall showed maximum growth when subjected to maximum stress. Growth under stress decreased as the stress decreased. This technique was used to measure the response of the sporangiophore to a light stimulus; the response is measured directly from the stress relaxation curve. Stress/strain measurements were also conducted on the stage IVb Phycomyces sporangiophores in order to further characterize the mechanical properties of the growing zone. It was found that the stress/strain ratio was invariant to the strain rate within the ranges tested but the stress/strain ratio did increase with larger loads, i.e., the stress/strain ratio shows non-linear behaviour.