1994 Fiscal Year Final Research Report Summary
Ripening characteristics and chilling sensitivity in Chinese pear fruit.
| Project/Area Number |
05660034
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
園芸・造園学
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| Research Institution | Okayama University |
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Principal Investigator |
NAKAMURA Reinosuke Okayama Univ., Fac. Agr. Professor, 農学部, 教授 (70021053)
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| Co-Investigator(Kenkyū-buntansha) |
KUBO Yasutaka Okayama Univ., Graduate School of Natural Sci. and Technol. Assistant Professor, 大学院・自然科学研究科, 助手 (80167387)
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| Project Period (FY) |
1993 – 1994
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| Keywords | Pear / Chinese pear / Fruit ripending / Ethylene biosynthesis / Chilling disorder / Gene for ethylene biosynthesis / Postharvest characteristics of fruit |
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| Research Abstract |
1. Ripening characteristics : Varietal difference of ripening behavior in Chinese pear fruit was studied in term of ethylene production using ten cultivars. Chinese pear fruit is long known to be one of the climacteric fruits which produce large amount of ethylene during ripening. In this study, however, we found that the fruit of two cultivars did not produce ethylene at ripening stage, though produced large amount of ethylene by wounding. From the determination of ACC synthase and ACC oxidase, the two key enzymes in thylene biosynthesis, ethylene biosynthesis of the fruit which not be producd ethylene during ripening was shown to be limited by low level of ACC synthase activity.
2. Chilling sensitivity : Varietal difference of chilling sensitivity was determined by using the whole fruit or callus tissue derived from fruit of thirteen cultivars in Chinese pear. Browned flesh was observed on the fruit or callus tissue of four cultivars after two or three weeks at 5 c. From the determination of electrolyte leakage, this disorder seemed to be low temperature disorder.
It was shown in this study that the chilling sensitivity of chinese pear fruit differed clearly in accordance with cultivar.
3. Molecular biological analysis of ethylene biosynthesis : In order to study on the differences of ethylene biosynthesis observed among different cultivars in Chinese pear fruit, partial cloning of cDNAs for ACC synthase and ACC oxidase was carried out. In this study, DNA and amino acid sequences of cloned DNA fragments for ACC oxidase was analyzed successfully. Now, homology analysis of cloned DNA fragment for ACC synthase are carring out. Furthermore, study on control of gene expression for ACC synthase and ACC oxidase is followed in near future.
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