Dissertation
Use of 1-methylcyclopropene and hydrogen peroxide to study apple ripening physiology
Washington State University
Doctor of Philosophy (PhD), Washington State University
05/2008
DOI:
https://doi.org/10.7273/000005682
Abstract
Unintended consequences of the ethylene action inhibitor 1-methylcyclopropene (1-MCP) are increased susceptibility to rot and decay pathogens, and fruit failure to develop aroma volatiles. In 1-MCP-treated apples, the effects of hydrogen peroxide (H2O2) to trigger ethylene biosynthesis and signaling were investigated. Transcription of antioxidative enzyme genes, antioxidant capacity, and catalase activity also were examined. H2O2 caused an increase in ethylene emission in 1-MCP-treated Golden Delicious and Delicious apples. In Golden Delicious , an increase in transcription of Md-acs1 in 2005 and Md-acs3 in 2006 matched the onset of the ethylene burst. In 2005, transcript levels of the putative ein2, Md-acs1, Md-etr1, and Md-ers1 were lower in fruit treated with 3 [mu]l l-1 1-MCP and dipped for an hour in 30 mM H2O2, compared to treated and untreated fruit dipped in water. In 2006, transcription of Md-ers1 increased in fruit treated with 1[mu]l l-1 1-MCP dipped in 30 mM H2O2 compared to treated fruit dipped in water. In 2005, transcript levels of Md-gpx and putative sod and cat increased over time in 1-MCP-treated water-dipped fruit compared to the other treatments. In contrast, transcript levels of putative apx varied with treatments and year. Constantly, 1-MCP-treated fruit always had lower catalase activity compared to untreated ones. In 2006, dipping fruit in H2O2 significantly increased catalase activity during the first 12 days overall, however exogenous H2O2 did not significantly change catalase activity of 1-MCP-treated fruit. H2O2 infiltration in Delicious apples after storage significantly decreased catalase activity. In 2005, dipping 1-MCP- treated fruit in H2O2 delayed a decrease in total water-soluble antioxidant capacity by a minimum of nine days. In 2006, 1-MCP significantly prevented a change in total water-soluble antioxidant capacity caused by H2O2. In addition, while 1-MCP-treated apples suffered from higher rot incidence compared to untreated ones, those treated with H2O2 had higher induction of PR2 and PR5; two pathogenesis-related proteins linked to heightened disease resistance. With 1-MCP it is difficult to ascertain treatment status or effectiveness. Md-acs1 and Md-pg, two gene candidates as molecular markers of 1-MCP application were tested using RT-PCR. Both genes are effective molecular markers for 1-MCP application at harvest, after storage, when exposed to exogenous ethylene, and regardless of formulation.
Metrics
4 File views/ downloads
26 Record Views
Details
- Title
- Use of 1-methylcyclopropene and hydrogen peroxide to study apple ripening physiology
- Creators
- Paul Guy Lėvesque
- Contributors
- John K. Fellman (Chair)Matthew David Whiting (Committee Member) - Washington State University, Department of HorticultureGerald E Edwards (Committee Member) - Washington State University, School of Biological SciencesMohan G N Kumar (Committee Member) - Washington State University, Department of Horticulture
- Awarding Institution
- Washington State University
- Academic Unit
- Department of Horticulture
- Theses and Dissertations
- Doctor of Philosophy (PhD), Washington State University
- Publisher
- Washington State University
- Number of pages
- 135
- Identifiers
- 99901054761301842
- Language
- English
- Resource Type
- Dissertation