Respiratory and Glycolytic Response of Suspension-cultured `Passe Crassane' Pear Fruit Cells to Elevated CO2 Concentrations

Abstract

Suspension-cultured `Passe Crassane' pear fruit (Pyrus communis L.) cells in aging media were ventilated with air or air + 20% CO 2 for 4 days at 26C. Cells exposed to elevated CO 2 exhibited reduced respiration (0 2 consumption). Ethylene production of both air and CO 2 -treated cells also declined to barely discernible levels by day 3. Fructose 6-phosphate (F6P) accumulated, while levels of fructose l,6-bisphosphate (F1, 6-P 2 ), and activities of ATP and PPi phosphofructokinases (PFK and PFP) declined in response to elevated CO 2 . These results indicate an inhibitory effect of CO 2 at the site of action of both phosphofructokinases in the glycolytic pathway, which could account, at least in part, for the observed reduction in respiration. The responses to elevated CO 2 levels of the cell suspension system and intact pear fruit ventilated with air + 10% CO 2 are compared, revealing a close similarity.