Abstract: The leaves at the different position, the basal, the middle and the upper, were examined with TEM. The content of chlorophyll and photosynthetic rate in those leaves was measured. The ultrastructure of chloroplast varies with the different position of leaves. The amount of grana lamellae, stroma lamellae and stroma increased generally with the rising position of leaves. That of the ear leaf at the middle position, was the highest than that of the others. In the upper leaf, the amount of grana lamellae, stroma lamellae and stroma was reduced. Also, the content of chlorophyll and the photosynthetic rate in the ear leaf was higher as compared with that is the other positional leaves. The observations revealed that the tendency of the variation in ultrastructure of the leaves at different position was in conformity with photosynthetic properties. The ultrastructure and function of ear leaf were better than that of other leaves.

Key words: Maize, Leaf, Ultrasturcture of chloroplast, Photosynthetic rate, Content of chlorophyll