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Lipoxygenase in relation to the ripening and softening of Actinidia fruit

Chen Kunsong, Xu Changjie, Lou Jian, Zhang Shanglong, Ross G S

Lab. of Fruit Molecular Physiology,Department of Horticulture,Zhejiang University Hua Jia Chi Campus.Hangzhou 310029,Zhejiang；New Zealand

Abstract

Kiwifruit (Actinidia) was used to investigate the effects of different treatments on the changes of lipoxygenase (LOX) and fatty acids composition, and the relationhsip between LOX and ethylene production in ripening fruits so as to inquire into the role of LOX in the ripening and senescing o f fruit. There was a negative relationship between the increase in LOX activity and decrease in fruit firmness in the fruits stored at 20℃; When fruit was stored at 0℃, LOX activity was markedly inhibited and its greatest activity was only 1/3. 4 of that in the fruit stored at 20℃, the fruit ripening was delayed as well. The main fatty acids in ripening kiwifruit were palnitic (16:0) stearic (18:0), oleic (18:1), linoleic (18:2) and linolenic (18:3) acid. Significant changes in the unsaturated fatty acids did occur and no marked changes in the saturated fatty acids were observed in the fruits stored at 20℃, the proportions of linoleic acid (18:2) and linolenic acid (18:3) decreased in fruits stored for 5 d and then increased quickly while the proportion of oleic acid (18:1) decreased ; The fatty acid content did not change significantly in the fruits stored at 0℃. Exogenous ethylene treatment led to an increase in LOX activity and hastened fruit ripening when the fruits were stored at 20℃. The significance of these results is discussed, in terms of a role for LOX in the ripening of kiwifruit.

Key words: Lipoxygenase;Kiwifruit;Fatty acids;Ethylene;Ripening;Softening

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Citing This Article：

Chen Kunsong, Xu Changjie, Lou Jian, Zhang Shanglong, Ross G S. Lipoxygenase in relation to the ripening and softening of Actinidia fruit. Acta Physiol Sin 1999; 51 (2): (in Chinese with English abstract).