果実の微量エチレンの生合成

Abstract

To demonstrate whether system I ethylene is synthesized via the ACC (1-aminocyclopropane-1-carboxylic acid) -ethylene pathway, as well as system II ethylene, toma-to and mume fruits at preclimacteric stage and cucumber fruit were treated with aminooxy-acetic acid (AOA), a competitive inhibitor of ACC synthase, and salicylic acid (SA), an inhibitor of ethylene forming enzyme (EFE).1. In the intact fruits of tomato and mume, the production rate of system I ethylene was inhibited effectively by the absorption of AOA and/or SA through peduncles. ACC content was decreased by the treatment with AOA, and increased by SA. Similar results were also obtained when tissue slices were used.2. In the cucumber fruit segments, synthesis of system 1 ethylene was inhibited marked-ly by vacuum-infiltration with AOA and/or SA. ACC content in the segments was decreased by the treatment with AOA, and increased by SA.3. In intact tomatoes harvested during the climacteric stage, exposure to 45°C complete-ly inhibited EFE activity and ethylene synthesis. However, the same treatment administered to fruits at the preclimacteric stage reduced system I ethylene to less than 50% of control fruits.The data suggest that most of the ethylene evolved by systems I and II is synthesized via the ACC-ethylene pathway.