Influence of Fruit Development Stage on the Physiological Response to Ethylene in Cantaloupe Charentais Melon

Abstract

An experiment has been designed and performed using Cantaloupe Charentais melon as climacteric fruit with the aim of finding out at which point of their development they are able to sense the plant hormone ethylene. Fruit were harvested at 20, 25, and 35 days after pollination (DAP), treated for 5 days at 20 °C with 5 ppm of ethylene, and stored for a further 10 days. Nontreated wild type fruit was used as control. Ethylene-treated genetically modified 1-aminocyclopropane-1-carboxylic acid oxidase antisense fruits with inhibited autocatalytic ethylene production were also used to avoid masking effects because of endogenous ethylene produced by control fruits. Ethylene-treated wild type fruits with 25 DAP were able to produce autocatalytic ethylene. A climacteric respiration increase was observed in treated wild type fruit with 25 and 35 DAP. The degreening of the rind was induced by ethylene in the youngest fruit, showing a total dependence on the hormone for its activation. Loss of pulp firmness induced by exogenous ethylene was found only in 20 DAP-fruit. The existence of ethylene-dependent and developmental factors in the regulation of this ripening process was observed.