Abstract: In order to investigate whether postharvest O3 treatment can counteract the negative effect of preharvest 1-(2-chloropyridin-4-yl)-3-phenylurea (CPPU) treatment on kiwifruits based on macroscopic electrical properties, the relationship between postharvest physiology, quality and electrical properties was studied on ‘Qinmei’ kiwifruit treated with 20 mg/L CPPU at 28 days after flowering and then treated with 70 mg/m3 O3 for 2 hours every 15 days during postharvest storage at (0 ± 1) ℃ and relative humidity of 90%–95% . The results showed that CPPU + O3 treatment led to significantly higher catalase (CAT) activity, VC and titratable acid (TA) content and significantly lower respiratory rate, polygalacturonase (PG) and cellulase (Cx) activities than did CPPU treatment alone. Postharvest O3 treatment could weaken the negative effect of CPPU treatment on kiwifruit. The characteristic frequency for CPPU-treated kiwifruit was 0.1 kHz among the selected 24 frequencies, while the characteristic frequency for both control and CPPU + O3 treated kiwifruit was 3 980 kHz, which further indicates that O3 can weaken the negative effect of CPPU treatment on kiwifruit through macroscopic electrical characteristics.

Key words: 1-(2-chloropyridin-4-yl)-3-phenylurea, ozone, kiwifruit, physiological quality, electrical properties