Abstract: Ginkgo(male and female) was selected to measure the changes in some photosynthetic characteristics and ultrastructure of chloroplasts during natural senescence of its leaves. The results showed that net photosynthetic rate and chlorophyll (Chl) content decreased during leaf senescence, while the activities of SOD, CAT and APX increased at first and then decreased, which resulted in the accumulation of MDA. In chloroplasts thylakoid membranes became loose gradually, whereas the number and size of osmiophilic granule increased till the chloroplasts disappeared. There were no variations between male and female in their physiological indexes.

Key words: Ginkgo, leaf senescence, photosynthetic characteristic, chloroplast, antioxidase