Gum Accumulation of Japanese Apricot Fruit (Prunus mume Sieb. et Zucc.) was Expedited by Jasmonate

Investigations were made into the effects of ethylene and jasmonate on gum formation of Japanese apricot fruit (Prunus mume Sieb. et Zucc.). We treated ‘Benisashi’ and ‘Nanko’ fruit that had been artificially wounded with a stainless steel needle and examined the relation between the formation of ethylene and gum accumulation. In addition, we treated ‘Benisashi’ fruit with ethephon, 1-methylcyclopropene (1-MCP), methyl jasmonate (JA-Me), ibuprofen, and aminoethoxyvinylglycine (AVG) to investigate the relation of these chemicals with gum accumulation. Artificial wounding induced ethylene evolutional though the gum formation was not necessarily induced. Treatment with ethephon and 1-MCP did not significantly affect fruit gumming induced by artificial wounding, whereas treatment with JA-Me accelerated gum formation. Note also that JA-Me treatment induced gum formation in intact fruit whereas ibuprofen treatment reduced gum formation. In contrast, AVG treatment did not affect gum formation of intact fruit. These results show that JA-Me expedites gum formation of Japanese apricot fruit. Moreover, ibuprofen treatment before the rapid mesocarp development stage significantly suppressed the percentage of gummed fruit.