Regulation by CO2 of 1‐aminocyclopropane‐1‐carboxylic acid conversion to ethylene in climacteric fruits

Abstract

Cheverry, J. L., Sy, M. O., Pouliquen, J. and Marcellin, P. 1988. Regulation by CO2 of 1‐aminocyclopropane‐1‐carboxylic acid conversion to ethylene in climateric fruits. ‐ Physiol. Plant. 72: 535–540.A high CO2 concentration (20%) at 20°C rapidly and strongly inhibited the development of the climacteric ethylene burst in apple (Malus domestica Borkh. cv. Granny Smith) and avocado (Persea americana Mill. cv. Fuerte) fruits and did not change 1‐aminocyclopropane‐l‐carboxylic acid (ACC) content. Treatment with 20% CO2 markedly decreased ACC‐dependent ethylene biosynthesis at 20°C in climacteric pericarp tissues. It is suggested, therefore, that high CO2 levels inhibit conversion of ACC to ethylene.Synthesis of the ethylene forming enzyme (EFE) was enhanced when intact preclimacteric apples or early climacteric avocados were pretreated for 40 h with 10 μ11‐1 ethylene. When CO2 (20%) and ethylene were both applied, a reduced stimulatory effect of ethylene on EFE synthesis was observed. A high CO2 concentration enhanced EFE acivity in excised tissues of apples and avocados incubated with ACC (2 mM) and cycloheximide (1 mM) or 2–5‐norbornadiene (5 ml 1‐1). In the autocatalytic process, 20% CO2 antagonized the stimulation of EFE synthesis by ethylene, but promoted EFE activity.