Effects of Killing by Heat or Desiccation on Membrane Structure in Pea Roots

Abstract

Radicles of dry pea seeds were killed by heating at temperatures up to 160°C, and root tips excised from pea seedlings were killed by desiccation. The effect of these treatments on the appearance of membranes was studied in the electron microscope after fixation and thin-sectioning and after freeze- fracturing, After fixation, membranes from dead tissue appeared modified in various ways compared with membranes from control tissue, whereas after freeze-fracturing they appeared unchanged. It is argued that heating and desiccation denature or disorganize structural protein in membranes but that they do not affect the lipid structure of the membrane.