Abstract:This paper made comparative study on the tissue structures of leaf,root and stem of the three Yunnan wild rice species and cultivated rice via hand-held slicing.It was found that (1) The tissue structures of leaf,root and stem between Yunnan wild rice and cultivated rice have significant differences,especially between the Jinghong Oryza meyeriana Baill.,Jinghong O.officinalis Griff.and cultivated rice.(2)In the leaf of main vein,Jinghong O.meyeriana Baill.has no gas chambers structure and the number of vascular bundles are the least with smaller vascular bundles areas,Jinghong O.officinalis Griff.and O.rufipogon Wall.have more than one vascular bundle and gas chambers structure,and the diameter of them are larger than cultivated rice,while there are two gas chambers in cultivated rice.(3)The structure of stem of Jinghong O.meyeriana Baill.is the smallest,and the vascular bundles is the fewest;The arrangement of vascular bundles is different in the stems wall from other rice.Jinghong O.officinalis Griff.and O.rufipogon Wall.have thicker stem and stem wall,more vascular bundles,and O.rufipogon Wall.stem exists aerenchyma structure.(4)In the root,O.rufipogon Wall.has more vessels,larger diameter of vessels and larger areas of stele than that of cultivated rice.O.rufipogon Wall.has exodermis grow casparian dots which have the function of casparian strips.This study lays the foundation of understanding the internal structures of wild rice,suggesting the relationship between the structures and the growth potential of Yunnan wild rice,the strong ability to absorb nutrients and resist diseases and insect pests,and exploring and utilizing the excellent genetic characteristics of wild rice.