Submitted to: Acta Horticulture Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 12/1/2004
Publication Date: 6/10/2005
Citation: Rudell Jr, D.R., Buchanan, D.A., Mattheis, J.P. 2005. ETHYLENE INTENSIFIES BUT IS NOT A REQUIREMENT FOR METHYL JASMONATE-ENHANCED ANTHOCYANIN SYNTHESIS BY 'FUJI' APPLE FRUIT. Acta Horticulture Proceedings. doi: 10.17660/2004.636.55.
Interpretive Summary: Apple peel color is considered one of the most important commercial grading criteria for most cultivars. Elevated consumer preference can result from enhanced coloration of apples. While various cultural practices are used to help enhance and maintain optimum coloration, environmental factors may intercede, resulting in poor coloration. Chemical treatments that enhance coloration have long been sought to provide extra assurance that jasomonate (MJ) can provide red color enhancement of apple fruit, both under field and laboratory conditions. The present study indicates that red color augmentation elicited through MJ exposure is independent of ethylene, a plant growth regulator that has been shown to promote red coloration in apples albeit with mixed results. Additionally the combination of ethylene and MJ can provide further enhancement above that of MJ alone. Further enhancement of MJ promoted coloration by commonly available ethylene generating agricultural chemicals may provide further efficacy for the use of MJ applications in a commercial setting for coloration enhancement.
Technical Abstract: Exogenous methyl jasmonate (MJ) stimulates anthocyanin accumulation in apple fruit peel. Anthocyanin synthesis in some apple cultivars reportedly is also stimulated by exogenous ethylene, however, the role of ethylene action in regulation anthocyanin synthesis in apple fruit is unclear. MJ enhances ethylene sensitivity in various plants, therefore, studies were cnducted to evaluate the role of ethylene and MJ in stimulation of anthocyanin synthesis in immature 'Fuji' apple fruit. Following ethylene and MJ treatments, fruit were exposed simultaneously to UV-B and visible light, then pigments were extracted and analyzed by reverse-phase high performance liquid chromatography. Treatment with MJ alone enhanced anthocyanin accumulation including idaein, the major anthocyanin in apple fruit. Anthocyanin accumulation was further stimulated by treatment with MJ + ethylene. Treatment with the ethylene action inhibitor 1-MCP followed by MJ reduced red coloration over MJ alone. Treatment with ethylene or 1-MCP alone or ethylene+1-MCP had little effect on anthocyanin accumulation. Chlorogenic acid synthesis was also enhanced by treatment with MJ or ethylene, however, treatment with 1-MCP alone or with MJ decreased chlorogenic acid content. MJ enhanced production of hyperin, the major quercetin glycoside in peel tissue, while ethylene and 1-MCP had no effect on quercetin glycoside content when applied alone or in any combination. B-carotene synthesis was enhanced following MJ treatment, stimulated further by MJ plus ethylene, but was not enhanced by ethylene alone. The results indicate a synergistic response between ethylene and MJ or stimulation of anthocyanin synthesis. Threatments with ethylene alone or 1-MCP indicate a limited role for ethylene action in regulation of red color development by immature 'Fuji' apple fruit.