西藏茶叶稳定同位素特征与区域差异及环境因子关系分析

西藏茶叶具有高原茶品质特征,是助推西藏经济发展的重要高价值农产品。为探明西藏茶叶同位素特征,探索气象环境对茶叶同位素的影响,本研究收集了西藏不同海拔地区茶叶以及全国主产区茶叶样品,分析茶叶中稳定同位素值(δ¹³C、δ¹⁵N、δ²H、δ¹⁸O),同时收集部分采样点的环境气象信息,结合偏最小二乘法(PLS)探究西藏茶叶同位素特征及环境因子关联性。结果表明,西藏茶叶δ¹³C值分布于-31.9‰~-27.8‰之间,随海拔升高而降低,显著低于其他主产区样品(P<0.01),δ¹³C值主要与采样当月的日照时间和气温有关;西藏茶叶δ¹⁵N与其他主产区样品无显著差异,且与环境气象因子关联性较弱;δ²H值介于-111.5‰~-40.5‰之间,与环境气象因子关联性最强,受相对湿度等多种因素影响; δ¹⁸O值介于22.2‰ ~ 27.6‰之间,主要与气温关系密切。本研究结果为西藏茶叶产地特征挖掘提供了研究思路,为西藏茶叶品牌保护提供了一定的理论依据。

Characteristics of Stable Isotopes in Tibet Tea Differentiating With Other Regions and Relationship With Environment Variables

Tibet tea has distinguished plateau quality characteristics, which is one of the high value agricultural products of Tibet. To explore the characteristics of stable isotopes in Tibet tea and its relationship with the climate environment, this study collected tea samples from Tibet with different altitudes and from main producing area in China. Stable isotope ratios (δ¹³C、δ¹⁵N、δ²H、δ¹⁸O) of tea samples were analyzed, while environment climate information were collected from each sampling site. The relationship between tea isotope characteristics and environment climate variables were built using partial least squares (PLS). The results showed that δ¹³C values in Tibet tea were -31.9‰ ~ -27.8‰, decreasing with elevation. The δ¹³C in Tibet tea were significant lower than samples from other main producing area (P<0.01), associating with sunshine duration and temperature in the sampling month. There were no significant differences of δ¹⁵N values between Tibet tea and samples from other main producing area, and the correlation between δ¹⁵N and climate variables was weak. The range of δ²H was -111.5‰ ~ -40.5‰, and the correlation with climate variables was most strong among the isotopes investigated. The δ²H values was effect by various factors such as relative humidity. The δ¹⁸O values were 22.2‰ ~ 27.6‰, relating closely with temperature. The present study could provide new research idea for the exploring of origin characteristics in Tibet tea, which also could supply theoretical basis for the brand protection of Tibet tea.