Modeling High Temperature and Exposure Time Interactions on Pittosporum tobira Root Cell Membrane Thermostability

Excised roots of Pittosporum tobira Thunb. were exposed to temperatures of 25° to 60°C for 30 to 300 min before cell membrane thermostability was determined by electrolyte leakage procedures. Response to treatment temperature for each exposure duration was sigmoidal. The critical temperature causing injury to root cell membranes decreased linearily as exposure duration increased exponentially. A mathematical model to describe the interaction of treatment temperature and exposure duration on membrane thermostability is presented.