Studies on subspecies changes of rice in the Neolithic age by analysis of morphological characteristics of plant opal from Nanzhuangqiao site
从南庄桥遗址的稻硅酸体看早期水稻的系统演变

Analysis of plant opal has been proposed as an effective method to origin and evolution of crops To understand subspecies and its changes of rice cultivated at the Neolithic age with changes of times, 16 soil samples, 8 earthenware fragments and burned soils from 5 12 earth layers of Nanzhuangqiao site in Zhejiang, China were collected for analysis of plant opal Plant opals of rice were detected in 14 soil samples and 6 earthenware fragments and burned soils, from the periods of Majiabang (B C 4500 B C 3800) and Liangzhu (B C 3500 B C 2000) cultures, indicating that rice have been cultivated since B C 4000 years ago at the site or its around The results of analysis of morphological characteristic of plant opals of rice showed that the vertical, horizontal and lateral lengths appeared to rise and the b/a was the opposite Also the distributions of the vertical, horizontal and lateral lengths shifted to big value and that of b/a was the opposite with changes of times, indicating that there were changes to plant opals noted by large sized long shape during from Majiabang to Liangzhu cultures, By the results, it was proposed that the rice cultivated in the early period of the Majiabang culture were varied populations not differentiating, and japonica subspecies had increased with changes of times in the Neolithic age in Nanzhuangqiao site