Abstract: The 3-year-old‘Anliu’orange（Citrus sinensis Osbeck）grafted on Honglimeng（Citrus limonia Osbeck）was used as experimental material to study the effect of girdling on photosynthetic property and reactive oxygen metabolism of Citrus leaves. The results showed that ringing and sprial girdling decreased the chlorophyll relative content（SPAD），net photosynthetic rate（Pn），transpiration rate（Tr），stomatal conductance（Gs）and intercellular CO2 concentration（Ci）of leaves with different degrees after 30-day treatment. Girdling treatment had a long-term impact on leaf SPAD and Pn. The activities of antioxidant enzymes（SOD，POD and CAT）in leaves were improved after ringing and girdling. The antioxidant compounds（GSH and AsA）contents in leaves were significantly decreased at 30 d after treatment，then began rising to a peak and returned to a normal state slowly at last. The malondialdehyde （MDA）content was increased in all treatments，which was significantly increased compared with the control by ringing twice and girdling. These data showed that ringing and girdling in early stage affected photosynthetic metabolism of citrus leaves，and caused a series of antioxidation reaction and accumulation of reactive oxygen species in citrus leaves.

Key words: citrus, girdling, photosynthesis, reactive oxygen