Calcium effects on ethylene and ethane production and 1‐aminocyclopropane‐1‐carboxylic acid content in potato disks

Potato (Solanum tuberosum L. cv. Katahdin) disks produce ethyline in increasing amounts from 6 to 24 h incubation in buffer at pH 4.0. Ethylene production is increased 2–3 times in the presence of 50 mM CaCl2. Levels of endogenous 1‐amino‐cyclopropane‐1‐carboxylic acid (ACC) increase in parallel with ethylene production, and ACC levels are 3–5 times higher in calcium‐treated disks than in controls. Most of the calcium‐induced stimulation of ethylene production can be accounted for by its effect on ACC production, indicating that the primary effect of calcium is on a step of ethylene biosynthesis preceeding ACC production. However, calcium may also have an effect on conversion of ACC to ethylene, since a consistent increase in ACC‐de‐pendent ethylene production was observed in the presence of calcium. Production of ethane, a marker of lipid peroxidation, was reduced by calcium, so it is possible that membrane stabilization by calcium could be involved in its effects on ethylene production.