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Ripening characteristics and chilling sensitivity in Chinese pear fruit.

梨果实的成熟特性及冷敏感性.

基本信息

批准号：
05660034
负责人：
NAKAMURA Reinosuke
金额：
$ 1.34万
依托单位：
Okayama University
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1993
资助国家：
日本
起止时间：
1993 至 1994
项目状态：
已结题

项目摘要

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.

1.成熟特性：以10个梨品种为试材，以乙烯释放量为指标研究了中国梨果实成熟行为的品种差异。中国梨果实是一种成熟过程中产生大量乙烯的跃变型果实。然而，在本研究中，我们发现两个品种的果实在成熟期不产生乙烯，但通过伤害产生了大量的乙烯。从乙烯生物合成的两个关键酶ACC合成酶和ACC氧化酶的测定来看，果实成熟过程中不产生乙烯的果实的乙烯合成受到ACC合酶活性低的限制。冷敏性：以13个中国梨品种果实的全果或愈伤组织为材料，测定其冷敏性的品种差异。4个品种的果实或愈伤组织在5℃下贮藏2~3周后，果实或愈伤组织出现褐变现象，从电解质渗漏率的测定来看，这似乎是一种低温失调现象，说明不同品种梨果实对冷害的敏感性存在明显差异。乙烯生物合成的分子生物学分析：为了研究不同品种梨果实乙烯生物合成的差异，进行了ACC合成酶和ACC氧化酶基因的部分克隆。本研究成功地对所克隆的ACC氧化酶DNA片段进行了DNA和氨基酸序列分析。目前，已克隆的ACC合成酶DNA片段的同源性分析正在进行中。此外，对ACC合成酶和ACC氧化酶的基因表达调控的研究也将在不久的将来进行。