Ethylene Production by Albedo Tissue of Satsuma Mandarin (Citrus unshiu Marc.) Fruit

Isolated albedo tissue of Satsuma mandarin (Citrus unshiu Marcovitch, cv. Owari) fruit produced a large quantity of ethylene during incubation at 26 C in the dark. When sliced, albedo tissue began producing ethylene at an increasing rate until a maximum was reached after incubation for about 30 hours. Aged albedo discs which were capable of producing ethylene, actively converted l-[U-(14)C]methionine into both ethylene and carbon dioxide. In fresh tissue, almost no measurable conversion of radioactive methionine into ethylene took place. Conversion of labeled l-methionine into ethylene was totally inhibited by the addition of nonradioactive l-methionine or l-ethionine. It appears possible, from these findings, that methionine is a precursor of ethylene in the aged albedo discs. Ethylene synthesis in the aged albedo tissue was markedly reduced in the presence of cycloheximide, suggesting that there may be a rapid turnover of the ethylene-producing system, and that its formation involves protein synthesis. Actinomycin D exerted no effect.