Premium
Influence of leaf age, species and soil depth on the authenticity and geographical origin assignment of green tea
Author(s) -
Liu Zhi,
Zhang Yongzhi,
Zhang Yu,
Yang Guilin,
Shao Shengzhi,
Nie Jing,
Yuan Yuwei,
Rogers Karyne M.
Publication year - 2019
Publication title -
rapid communications in mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.528
H-Index - 136
eISSN - 1097-0231
pISSN - 0951-4198
DOI - 10.1002/rcm.8387
Subject(s) - fractionation , chemistry , isotope analysis , stable isotope ratio , isotope , isotope fractionation , isotopes of carbon , isotopes of nitrogen , nitrogen , photosynthesis , nutrient , environmental chemistry , botany , ecology , total organic carbon , biology , chromatography , biochemistry , physics , organic chemistry , quantum mechanics
Rationale Stable isotope fractionation occurring during leaf growth provides internal characteristics for identifying the geographical origin, traceability and authentication of tea. Studying the influence of leaf age, species and the relationship with the cultivated soil may reveal previously undocumented stable isotope fractionation mechanisms, and provide a deeper understanding of the physiological isotopic effects on the tractability and authentication accuracy of green tea to combat mislabeling and fraudulent conduct. Methods A total of 36 pairs of young (one bud with one leaf) and mature growth (older leaf) samples from two species of Longjing tea (Longjing #43 and Colonial cultivar) and corresponding cultivation soil samples from two different depth layers (0–20 cm and 20–40 cm) were collected in Westlake district, Hangzhou, Zhejiang province, China. Four stable isotope ratios (δ 13 C, δ 15 N, δ 2 H, and δ 18 O values) were measured using an elemental analyzer coupled with an isotope ratio spectrometer. Linear correlation and one‐way analysis of variance (ANOVA) statistical analyses were performed to investigate isotopic fractionation mechanisms during plant growth, and reflect the dynamic physiological processes from soil to leaf. Results The carbon and nitrogen isotope ratios (δ 13 C and δ 15 N values) reflected the absorption, migration and fractionation of carbon dioxide and nitrogenous nutrients during photosynthesis, nutrient uptake, nitrogen fixation and leaf respiration. The water isotope ratios (δ 2 H and δ 18 O values) reflected the use and fractionation of water by tea plants at different growth stages. Conclusions Considerable differences were found for hydrogen and oxygen isotope ratios according to leaf age, revealing complex isotopic fractionation mechanisms and possible interference factors. Leaf maturity effects should be considered, as they will influence the precision and accuracy of models when assigning the geographical origin, traceability and authentication of tea.