Chlorophyllase activities of the control kiwifruit declined continuously, while treated fruit showed the highest activity at day 2 and then decreased. However, no significant differences in chlorophyllase activities were observed between control and treated fruit during the entire experiment (Fig. 4A). Generally, chlorophyllase catalyzes the release of the phytol chain from Chl to produce Chlide, the first step in the Chl degradation pathway. Costa et al. (2005) reported that chlorophyllase activity increased quickly in ethephon-treated broccoli (Brassica oleracea L. var. Italica, c.v. Shogun), while the activity decreased continuously in ethylene-treated banana ( Yang et al., 2009). Therefore, the effect of ethylene on chlorophyllase activity can be different according to the system. In this study, chlorophyllase activity slightly increased in ethephon-treated kiwifruit during ripening as compared to the control.