Flavonoids are important phenolic compounds in tea plant since they have a large number of physiological functions for plants themselves and human beings. Tea samples (n = 151) harvested from 3 varieties, 9 plantation areas and 107 cultivars were analyzed to describe the attributes of catechins and flavonol glycosides in China. A support vector machine (SVM) classifier was built to recognize the assamica variety with 94.2 % accuracy. Accumulation of (-)-epicatechin gallate (ECG) and flavonol di-glycosides was especially observed in assamica variety, while (-)-epigallocatechin gallate (EGCG) and flavonol tri-glycosides were obviously accumulated in sinensis variety. The ratios of ECG/EGCG and flavonol tri-glycosides/flavonol di-glycosides could be used as indicators for distinguishing the different varieties and cultivars. Accumulation pattern of catechins and flavonol glycosides were mainly dependent on the genetic background of the cultivars rather than plantation locations. The increased hydroxyl groups at the C-ring of catechins and the extended sugar chain at the B-ring of flavonol glycosides could be considered as important rules of metabolite change during tea plant evolution. The mechanism of accumulation of flavonoids in various varieties and cultivars was also discussed.
Novel alternatives of perfluorooctane sulfonate (PFOS), chlorinated polyfluorinated ether sulfonates (Cl-PFAESs) are increasingly being detected in the aquatic and terrestrial environment. Previous studies mainly focused on aquatic biota; however, the knowledge about the ecotoxicological risk they pose to terrestrial plants was still lacking. In this study, the accumulation of two Cl-PFAES (6:2 and 8:2 Cl-PFAES) and PFOS in wheat seedlings at environmentally relevant levels (50 and 100 μg L −1 ) was investigated. Concentrations of Cl-PFAESs in the roots were an order of magnitude higher than those in shoots, indicating that they were primarily accumulated in the roots. The values of root and shoot bioconcentration factor was comparable between 6:2 Cl-PFAES and PFOS. However, these indexes of 8:2 Cl-PFAES were 42–91% higher and 70–76% lower than PFOS, respectively. As a result, 6:2 Cl-PFAES had a similar accumulation pattern as PFOS, whereas 8:2 Cl-PFAES was predominantly restricted to the roots, which might be attributed to their hydrophobicity and carbon chain length. In addition, at 250 mg L −1 of Cl-PFAESs, plant biomass and pigment content were 24–30% and 0.4–18%, respectively, which were lower than those of PFOS. As compared with PFOS, Cl-PFAESs induced higher levels of root membrane permeability, reactive oxygen species and malondialdehyde content, as well as reduced the activities of antioxidant enzymes and glutathione content. These suggested the occurrence of a severer oxidative damage and the breakdown of the antioxidant defence system in wheat cells. Therefore, we conclude that Cl-PFAESs might pose a higher potential threat to the environment than PFOS.
危险品化学品经营许可证（带存储）