Abstract: The microstructure and ultrastructure of three cultivated varieties of Oryza sativa ssp. japonica(Wuyujing 3, Wuyunjing 7, and Kanto 194) were investigated using light microscope and transmission electron microscope. The number of vascular bundles and air spaces in the main vein of the leaves in both Wuyujing 3 and Wuyunjing 7 was more than those of Kanto 194. Meanwhile, the grana lamellae of chloroplast were arranged closely and there was no gap in the middle of grana lamellae. The grana lamellae of chloroplast were arranged loosely and there were more gaps.These results showed that the microstructural and ultrastructural features of Wuyujing 3 and Wuyunjing 7 were correlated to their high yield characteristics, which lay a theoretical foundation for our future research.

Key words: rice, vascular bundle, air space, chloroplast, grana lamella