1999 Fiscal Year Final Research Report Summary
Physiological and molecular biological study on mechanism of senescence and quality changes of vegetables and investigation of keeping quality
| Project/Area Number |
09660022
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
園芸・造園学
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| Research Institution | Shizuoka University |
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Principal Investigator |
HYODO Hiroshi Shizuoka University, Faculty of Agriculture, Professor, 農学部, 教授 (40023452)
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| Project Period (FY) |
1997 – 1999
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| Keywords | Senescence / Broccoli / Ethylene / ACC synthase / ACC oxidase / Jasmonic acid / Cytokinin |
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| Research Abstract |
Rapid changes in metabolism proceed in vegetables after harvest, leading to senescence and quality detrioration. In broccoli florets (flower buds) senescence progressed rapidly after harvest at ambient temperatures. Ascorbate content declined sharply and chlorophyll loss occurred rapidly, leading to yellowing of florets. During senescence of broccoli florets ethylene production increased, reached a maximum and then declined. In parallel with ethylene production rate, ACC (1-aminocyclopropane-1-carboxylic acid) oxidase activity increased to reach a peak and declined thereafter. Enzymatic properties of ACC oxidase extracted from broccoli florets and purified from Escherichia coli transformed with broccoli ACC oxidase cDNA were investigated. Methyl jasmonate applied to broccoli florets induced and accelerated activities of ACC synthase and ACC oxidase, which resulted in enhanced rate of ethylene production. Methyl jasmonate promoted senescence, while cytokinin retarded the progress of senescence of broccoli florets by inhibiting ethylene production. Thus it will be possible to regulate senescence and quality changes of broccoli florets by controlling ethylene production and ethylene action. The best way for keeping quality and retarding senescence of broccoli florets is concluded to be low temperature storage which reduces metabolism and ethylene production at a basal low level.
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