Variation of the light stable isotopes in the superior and inferior grains of rice (Oryza sativa L.) with different geographical origins

• An unreported angle looking at biological factor that may improve the isotopic based traceability technique for rice.
• Abundance of light stable isotopes in rice grains are panicle position dependent.
• Stable isotope signals in different grain can differentiate cultivation areas.

Trying to explore a new research angle to increase the resolution and accessibility of isotopic based traceability technique, light stable isotopes (δ13C, δ15N, δD and δ18O) in the superior (SS) and inferior (IS) grains of a rice cultivar Daohuaxiang were analyzed with relatively limited sample numbers and adjacent sites in Fujin and Wuchang, Heilongjiang Province, PR China. Distribution of δ13C, δ15N and δ18O in the SS and IS grains were found to be different. δ18O and δD can discriminate rice cultivation areas. However, δ13C and δ15N values in Fujin and Wuchang overlapped when the differences between SS and IS were considered, thus δ13C and δ15N cannot be used to discriminate cultivation areas. This exploratory study indicate the variation of the light stable isotopes in the grains located on different panicle positions could be used to discriminate the geographical origin but still need further systematic consideration and verification.