基于稳定同位素的蚕茧与桑树品种鉴别OA

China is recognized as the earliest country to cultivate mulberry trees and domesticate silkworms,with a long history of silk culture.In recent years,the discovery of early silk remains in the Indus River Valley has sparked discussions on the origin of silk,highlighting the importance of establishing a traceability system for silk origin.Stable isotope fingerprinting techniques,such as δ13 C and δ15 N,can reflect geographical and environmental differences and have been successfully applied in agricultural product traceability.Through the"mulberry-silkworm-cocoon"system,this technology transmits isotopic information,thereby providing a basis for determining the origin of cocoons. Existing studies indicate that the isotopic composition of cocoons is influenced by the rearing environment,silkworm variety,and regional conditions,with regional factors potentially playing a more significant role than varietal differences.As mulberry leaves are the sole food source for silkworms,their isotopic characteristics directly affect the accuracy of cocoon traceability.Variations in mulberry variety,leaf position(e.g.,young vs.old leaves),and growing conditions lead to differences in isotopic values,which in turn influence the absorption and transformation of isotopes in silkworms.However,research on the effects of mulberry variety and leaf position on isotopic transmission remains insufficient. This study aimed to systematically investigate the influence of mulberry leaf isotopic characteristics on cocoons by analyzing the carbon and nitrogen stable isotope ratios of different mulberry varieties and leaf positions(considering sun-exposed and shaded growth conditions),as well as the corresponding isotopic composition of different silkworm cocoon varieties.The research focused on key aspects of isotopic transmission within the"mulberry—silkworm—cocoon"system,and for the first time,systematically integrated mulberry variety,micro-environmental leaf position(sun-exposed/shaded),and silkworm variety differences to comprehensively analyze their effects on the fractionation and transmission of carbon and nitrogen stable isotopes,addressing gaps in the fundamental mechanisms of existing research. Mulberry leaves from different varieties showed distinct δ13 C and δ15 N values.Leaves from three Japanese-origin mulberry varieties had δ15 N values below-3‰,while those from Yunnan-origin varieties ranged between-3‰ and-2‰,and Zhejiang-origin leaves exhibited more positive δ15 N values.For leaves at different positions,sun-exposed and shaded leaves displayed different isotopic patterns.In sun-exposed leaves,δ13 C generally decreased from the top to lower leaves,and the decline in δ15 N with lower leaf position was more distinct due to clearer photosynthetic activity and nitrogen allocation priority.In shaded leaves,however,the top leaves showed the lowest δ13 C values,while nitrogen distribution was more uniform.Significant differences in carbon and nitrogen stable isotope ratios were also observed among different silkworm varieties.Tussah silkworm cocoons had the highest δ13 C values,while domestic silkworm cocoons showed more negative δ13 C values compared to the other four varieties.Among locally reared silkworm varieties in Zhejiang,however,no significant differences in carbon and nitrogen isotope ratios were detected. This study confirms that carbon and nitrogen stable isotope ratios can effectively distinguish different mulberry varieties and silkworm cocoon types.It also reveals that isotopic values vary even among mulberry varieties from the same region,and that factors such as leaf position and growth orientation affect isotopic composition.Therefore,to improve traceability accuracy,future research should focus on systematically establishing an isotopic database that covers different varieties,producing regions and growing conditions,and combining multivariate statistical analysis or machine learning methods to develop more robust discriminant models.