1-Methylcyclopropene (1-MCP) inhibits ethylene production of durian fruit which is correlated with a decrease in ACC oxidase activity in the peel

Fruit of cv. Monthong durian (Durio zibethinus Murr.) were treated for 12 h with 0 (control) and 500 nL L-1 1-methylcyclopropene (1-MCP) at 25 degrees C and were then stored at a temperature of 15 degrees C. The fruit were transferred from a temperature of 15 degrees C to a temperature of 25 degrees C within a 3-day interval. 1-MCP treatment did not affect the relatively low rate of ethylene production in fruit stored at a temperature of 15 degrees C. In contrast, 1-MCP delayed the dramatic increase in ethylene production in fruit that were transferred from a temperature of 15 degrees C to a temperature of 25 degrees C. It is well known that the peel (husk) produces much more ethylene than the pulp, hence, the effects of 1-MCP on the peel will likely overshadow any effect on the pulp. In the peel, 1-MCP had no effect on 1-aminocyclopropene-1-carboxylic acid (ACC) synthase activity, but decreased ACO activity. ACC levels in the peel were not affected by the treatment at 25 degrees C. In the pulp, by contrast, ACO activity was not affected, but ACS activity was not inhibited at 25 degrees C and ACC levels were found to be lower, after the 1-MCP treatment. It was concluded that 1-MCP seems to inhibit ethylene production of durian mainly by preventing an increase in ACC oxidase activity in the peel. (C) 2015 Elsevier B.V. All rights reserved.