| EGCG (epigallocatechin-3-gallate) is one of the crucial important factors in tea quality. It is also the core component of tea polyphenols that have physiological activity and wide uses. This study investigated two aspects: screening specific tea plant (Camellia sinensis (L.) O. Kuntze) resources with high EGCG content and improving the EGCG content of tea plant's new shoots by exogenous Induction. The exogenous induction molecular mechanism, the differential display of proteome and transcriptome in the course of increasing the EGCG content of new shoots through exogenous induction, was also studied.1. The EGCG content of spring tea, summer tea, autumn tea in 45 varieties or lines were analyzed by isocratic elution high performance liquid chromatography. The result was as follows: In spring tea, summer tea, autumn tea, the EGCG contents in 45 varieties or lines were in the range of 1.45%~18.03%, 0.97%~16.16%, 1.38%~ 16.75%, the averages were 12.19%, 10.59%, 7.67%, respectively. The annual average was 10.15%. There are 11 varieties and lines in which the annual average EGCG content exceeded 13%. In particular, the 1005 line annual average EGCG content reached to 15.34%, its EGCG/total catechins came to 75.30%~ 80.57% (general level is 50%), (EGCG+ECG) / total catechins reached 85.24-88.32%(general level is 70%) . In addition, this study revealed findings: EGCG content of the same varieties and lines was determined by the level of growth prosperity, not by the season in the same year; and the capability of gallic acid acylation varied with the varieties and lines.2. Utilizing Fu Ding Da Bai Cha, Maoxie, Tie Guan Yin, Benshan, and Fuyun 6# as materials, 6 non-harmful inducers (IDl, ID2, ID3, ID4, IDS, ID6) were sprayed on the above tea plant cultivars to probe the exogenous induction effect. The results were as follows: The IDl is the best inducer, that is, the relative EGCG content of new tea shoots could be increased by 20.15%~25.00%; and IDl optimum induction time for Maoxie cultivar was 5d~7d. The IDl optimum dilution factor for Maoxie cultivar was within the range of 100~150. In spring tea, summer tea, autumn tea, IDl could increase the EGCG content of new tea shoots in both the Fu Ding Da Bai Cha and Tie Guan Yin cultivars by 17.48%~25.12% and 16.18%~22.89%, respectively.3. Utilizing both Fu Ding Da Bai Cha and Tie Guan Yin cultivars as materials, an experiment was done to systemically investigate the effects on both the quality of biochemical components of fresh leaves and the quality of tea beverage in the process of inducing and improving the content of EGCG in tea with ID1. The results showed that the contents of polyphenols and soluble sugar were significantly improved, and the content of rough fiber decreased. However, there were few affects on biochemical components such as caffeine, amino acids and chlorophyll during the induction process. The flavor of green tea (Fu Ding Da Bai Cha) and oolong tea (Tie Guan Yin), both manufactured from exogenous induction new tea shoots, was fairly mellow; taste was a little harsh; and color was insufficiently bright, i.e., the green tea and oolong tea beverage quality was affected negatively by the process of induction. Besides, exogenous induction could improve the persistence of new tea shoots. So, exogenous induction could not improve tea beverage quality of green tea and oolong tea, but it could improve the health protection quality of fresh leaves and dry tea.4. Utilizing the Maoxie cultivar as material, the variation of proteome was studied in the course of increasing tea plant EGCG content through exogenous induction with ID1. The technique of the preparation protein sample extracting from tea plants, the electrophoresis and the staining was improved. Thus, the technique of immobilized pH gradient two-dimensional polyacrylamide gel electrophoresis adapted to tea plant proteins was established for the first time. It was used to isolate the total proteins of induced tea shoots and normal shoots. A two-dimensional polyacrylam...
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