Abstract: The result of plant opal analysis on Longnan neolithic site of Wujiang County, Jiangsu Province, locating at the lower part of Yangtze Valley,showed that about 5000 years ago rice cutivation had been developed in this site. According to the analysis of plant opal the japonica and indica type could be distinguishedaffirmatively, and the rice population of the site was a japonica type.

Key words: Rice cultivation, Plant opal, Neolithic site, Agricultural history

关键词: 植物蛋白石, 新石器遗址, 水稻, 稻作起源