Mechanical Stress, Storage Time, and Temperature Influence Cell Wall-degrading Enzymes, Firmness, and Ethylene Production by Cucumbers
Mechanical Stress, Storage Time, and Temperature Influence Cell Wall-degrading Enzymes, Firmness, and Ethylene Production by Cucumbers
复制标题
机械应力、储存时间和温度影响黄瓜细胞壁降解酶、硬度和乙烯产生
DOI：
10.21273/jashs.112.4.666
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发表时间：
1987
影响因子：
1.9
通讯作者：
D. Kretchman
中科院分区：
文献类型：
--
作者：
A. Miller;J. Dalmasso;D. Kretchman
黄瓜（Cucumis sativus L.）果实（“Heinz 3534”）经受机械应力，然后贮藏48小时，表现出中果皮和内果皮的可见退化，这伴随着酶果胶甲基酯酶、过氧化物酶、多聚半乳糖醛酸酶和木聚糖酶的活性的几倍增加。所有这些酶的活性增加内果皮，而只有果胶甲酯酶和多聚半乳糖醛酸酶增加中果皮，果胶甲酯酶，过氧化物酶和多聚半乳糖醛酸酶增加外果皮。此外，果胶甲酯酶，过氧化物酶和多聚半乳糖醛酸酶的活性增加较少时，黄瓜储存在0°或10°C与25°或38°机械应力后。机械应力后，或不强调，并存储8或48小时的黄瓜存储仅8小时，没有表现出一致的酶活性的显着增加。在25°和38°下贮藏8 h后，内果皮硬度均低于对照，但在贮藏48 h后，内果皮硬度下降不明显，中果皮硬度不受贮藏温度和时间的影响。机械应力后在0°下储存8小时和在0°下储存48小时显著刺激乙烯产生，但不受所有其他处理和储存制度的影响。这些数据表明，机械应力诱导黄瓜果实的主要组织中的生化和形态变化，但组织硬度和/或乙烯的产生不会作为这些变化的指标。此外，机械应力的影响似乎不通过乙烯的作用来介导。
Cucumber (Cucumis sativus L.) fruit (‘Heinz 3534’) subjected to mechanical stress followed by storage for 48 hr exhibited visible degeneration of the mesocarp and endocarp, which was accompanied by several-fold increases in the activity of the enzymes pectin methylesterase, peroxidase, polygalacturonase, and xylanase. The activity of all these enzymes increased in the endocarp, whereas only pectin methylesterase and polygalacturonase increased in the mesocarp, and pectin methylesterase, peroxidase, and polygalacturonase increased in the exocarp. Further, the increase in the activity of pectin methylesterase, peroxidase, and polygalacturonase was less when cucumbers were stored at 0° or 10°C vs. 25° or 38° after mechanical stress. Cucumbers stored for only 8 hr after mechanical stress, or not stressed, and stored for 8 or 48 hr showed no consistent significant increases in enzyme activity. Endocarp firmness of fruit stored at 25° or 38° for 8 hr after mechanical stress was lower than that of unstressed fruit, but this decrease was not evident after 48 hr of storage, and mesocarp firmness was not affected by mechanical stress regardless of storage temperature or time. Ethylene production was stimulated significantly by 8-hr storage at 0°, following mechanical stress, and by 48-hr storage at 0°, but was unaffected by all other treatment and storage regimes. These data indicate that mechanical stress induces biochemical and morphological changes in the major tissues of cucumber fruit, but tissue firmness and/or ethylene production will not serve as indicators of these changes. Moreover, the effects of mechanical stress do not appear to be mediated through the action of ethylene.