绿茶鲜叶矿质元素指纹信息成因及变化机理

Tea is a typical product of geographical indication. It could provide theoretical and technical supports for the supervison and management of famous high-quality tea to study its origin traceability by multi-element fingerprinting technique. The precondition of its application is to verify the elements mainly associated with geographical origin and their stability among different harvest seasons or years. Green tea leaves of common varieties, topsoil and parent soil samples will be collected from different regions in diffferent seasons for three years in this project. And the obtained tea leaves and soil samples will be taken as experimental materials. The contents of 56 elements in the samples will be determined by inductively coupled plasma optical emission spectroscopy. The 56 element contents of tea leaves and soil samples will be as study subjects. Combined with statistical methods such as analysis of variance and correlation analysis, the relationships between multi-element fingerprints of green tea leaves and location, genotype, harvest season, or year will be analyzed. The contribution rates of location, genotype, harvest season, or year to the variation of multi-element contents will be calculated. In addition, the relationships of multi-element fingerprints between green tea leaves and topsoil or parent soil will be further studied. Through above analysis, the formation reason and change mechanism of multi-element fingerprints of green tea leaves will be made clear. The elemental indicators closely related to tea geographical origin will be selected. This project could provide theoretical basis for the study and application of identifying the geographical origin of tea by multi-element fingerprinting technique.

茶叶是典型的地理标志产品，其产地矿质元素指纹溯源研究能为名优茶的监管提供理论和技术支撑。确定与原产地密切相关的矿质元素及其在季节、年际间的稳定性是此技术应用的前提。本项目以连续3年于不同季节在不同地区采集共有的绿茶品种的鲜叶及种植园的表层和母质土壤样品为试验材料；利用电感耦合等离子体光谱仪检测样品中56种矿质元素的含量，将绿茶鲜叶和土壤样品中这56种元素的含量作为研究对象。结合方差分析、相关分析等统计学方法，分析绿茶鲜叶矿质元素指纹信息与地域、基因型、季节及年际的关系；解析地域、基因型、季节、年际等因素对绿茶鲜叶矿质元素指纹信息形成的贡献率；进一步分析绿茶鲜叶矿质元素指纹与种植地域表层和母质土壤矿质元素指纹的关系；明确绿茶鲜叶产地矿质元素指纹形成的原因，揭示其矿质元素指纹信息变化机理。筛选出与茶叶种植地域密切相关的矿质元素指纹信息，为茶叶产地矿质元素指纹溯源技术的研究与应用提供理论依据。

为了维护名茶品牌形象，规范市场秩序，提高产品竞争力，保障消费者合法权益，本项目分别比较不同产地、品种、季节、年际间茶叶鲜叶矿质元素指纹信息间的差异；综合分析产地、品种、季节、年际及其交互作用等因素对茶叶鲜叶矿质元素指纹信息的影响，分别筛选出茶叶鲜叶中与地域、品种、季节等因素密切相关的元素；分别研究茶叶与表层土壤、母质土壤及表层土壤与母质土壤中矿质元素含量间的关系，筛选出茶叶鲜叶中与母质土壤密切相关的元素；结合上述结果确定茶叶鲜叶矿质元素指纹信息成因及变化机理；基于与母质土壤密切相关，受品种、季节等因素影响较小的元素建立稳定的茶叶产地判别模型。结果表明，不同产地、不同品种、不同季节及不同年际茶叶鲜叶具有各自的矿质元素指纹特征。解析出产地、品种、季节、年际及其互作等各因素对茶叶鲜叶中各矿质元素含量的贡献率，结果显示，茶叶鲜叶中Ni、Cu、Rb、Sr、Cs和Tl的含量主要与地域相关；Na主要与季节相关；V、Cr、As、Se、Ir、Pt和Pb主要与年际相关；Co主要与地域×品种互作因素相关；Tm主要受误差的影响；其他元素含量受多种因素的影响，如Mg主要受季节和地域的影响；Ca主要受季节、地域×品种×季节、地域等因素的影响；Mn主要受地域×品种、品种、季节×年际等因素的影响；Fe主要受年际和地域的影响；Zn主要受年际和季节的影响；Mo主要受品种、地域×品种×季节×年际等因素的影响；Cd和Ba主要受地域、地域×品种×季节等因素的影响；La、Pr、Nd、Sm、Gd、Dy、Er、Yb主要受品种、季节×年际等因素的影响。茶叶鲜叶中Na、Ca、Ni、Se、Sr、Ba、La、Pr、Nd、Sm、Eu、Gd、Dy、Er、Pt、Al、As、Rb、Tl和Pb的含量与产地土壤中相关元素的含量呈极显著正/负相关（p＜0.01）。Ni、Rb、Sr、Ba和Tl与地域母质土壤密切相关，是较好的茶叶产地溯源指标。本项目研究结果为名优茶叶溯源提供了理论和技术支持。