Abstract:

In this paper, two rice varieties(Wuyunjing21 and Liangyoupeijiu) were used to detect polyphenol oxidase (PPO), ascorbic acid oxidase (AAO), glycolic acid oxidase (GO) activities of leaves for heading date of rice (Oryza sativa I )under the ambient atmosphere O3 concentration (Ambient) and O3 free air concentration enrichment (O3-FACE) conditions. Results showed that: elevated O3 concentration enhance the activities of PPO, AAO and GO after 67 days O3 treatment，Wuyunjing 21 increased these enzymes activity much than those of Liangyoupeijiu; however, after 79 day O3 treatment, elevated O3 concentration decreased GO, PPO and AAO activity, especially these enzymes activity reduction of Liangyoupeijiu were much than those of Wuyunjing 21.The results indicated that, Wuyunjing 21 have strong respiration by enhancing three respiration enzymes activity to dissipate of excess light energy and protect the photosynthetic apparatus for alleviating the damage of ozone on the photosynthetic apparatus of rice leaves. So we concluded that Liangyoupeijiu was more susceptible to ozone than Wuyunjing 21.