Abstract: 【Objective】The aim of this study is to discover the biological structure basis of transgenic rice expressing C4 photosynthesis enzymes and photosynthesizing highly and efficiently. 【Method】Using four transgenic rice lines over-expressing maize photosynthesis enzymes of phosphoenolpyruvate carboxylase (PEPC), pyruvate, othophosphate dikinase (PPDK), PEPC + PPDK, and rice nicotinamide adenine dinucleotide phosphate-malic enzyme (NADP-ME) as materials, and an untransformed wild type Kitaake as the control, the structures of stomata in leaves and vascular bundles in culms of the seedlings were observed with a scanning electron microscope and mesophyll cells were observed with a transmission electron microscope. 【Result】 Compared with the control, the density and the area of the stomata in leaves of the transgenic rice lines were greater, with the PPDK line greatest among the four lines. The density of stomata in the leaves of transgenic rice with two polymerizing genes (PEPC + PPDK) was increased, but the area of stomata was reduced. The stacking degree of chloroplast thylakoids in mesophyll cells was denser, and some thylakoids were arranged more orderly along the long axis of chloroplast for the transgenic rice lines than those for the WT. The transgenic rice lines exhibited thicker and stronger culms as compared to WT. Except for PPDK, all the transgenic rice lines had larger areas of the tissue structure performing substance-transporting function, such as the outer and inner vascular bundles and their catheter and sieve tubes in culms, as compared with WT. 【Conclusion】 More number and larger area of stomata in leaves and more developed vascular bundles in culms of C4 transgenic rice lines, all these structure characteristics were the basis of its, photosynthesizing highly and efficiently, and closely associated with the greater dry matter accumulation of seedlings.

Key words: Transgenic rice, C4 photosynthesis enzymes, Morphology, Stomata, Vascular bundle