摘要： The difference in protein content, MDH,POD and COD isozymes have been seenbetween lowland rice roots and upland rice roots during root growth and development. High pro-tein content has been examined in upland rice roots,but isozyme bands in lowland rice roots aremore than that in upland rice roots.Total area of POD isozyme bands at seedling and tilleringstages of upland rice is larger than that of lowland rice.The POD isozymes zymogram in the rootof upland rice is more stable compared with that of lowland rice.More COD isozyme numbershave been showed in roots of upland rice,but the relative activity of COD isozyme in roots of up-land rice at the seedling and tillering stages is lower than that of lowland rice.COD₇ band can beshown in upland rice root at flowering stage,but it is absent in lowland rice.Therefore,COD₇,band can be taken as an index for resistance of the upland rice to drought environment.

关键词: upland rice, lowland rice, cytochrome oxidase isozyme, polyacrylamide gel elec-trophoresis, drought tolerance