The effect of ethylene on the respiration, ethylene production, RNA and protein synthesis for apples stored in low oxygen and in air

Abstract

A comparison is made between the respiration rate and ethylene production of the whole fruit and the respiration rate, ethylene production, incorporation of 14C-uridine into an RNA fraction and of 14C-valine into a protein fraction of peel disks prepared from the fruit from Bramley's Seedling apples stored at 12° in air and in 3% oxygen. Results show that the respiration and ethylene production of the whole fruit is closely reflected in the behaviour of the peel disks in air, in low O 2 and on transfer from low O 2 to air. Ethylene appears to be the key to the increased rate of respiration and the other parameters including the development in the disks of a malate decarboxylating system (the malate effect) which appears to be a coupled system involving malic enzyme, pyruvate decarboxylase and alcohol dehydrogenase (NADPH 2-dependent). While oxygenous ethylene has a temporary stimulatory effect on the various systems investigated when applied in 3% O 2, autostimulation of ethylene production with attendant physiological action does not appear possible in low O 2. Both production and physiological action of ethylene appear to require relatively high concentration of O 2 for their full operation.