| Ancient tea tree resources are not only widely sought after in the tea market,but also have important significance for tea planting and breeding research.Based on the ancient tea tree resources which found in Jiuwan Mountain in Wangdong Township of Liuzhou,a number of unique ancient tea plant strains were selected by their morphological characteristics,and genetic diversity and relationship about them were studied by ISSR.The contents of water extracts,tea polyphenols,amino acids and alkaloids,catechins,amino acid composition of 36 strains ancient tea plants in two years and three seasons were analyzed by UV spectroscopy and HPLC.The suitability of this ancient tea tree resource was discussed by Combining sensory evaluation and biochemical composition analysis for the black tea and green tea made by ancient tea tree.The results are as follows:1.Genetic diversity and relationship :A total of 91 samples(87 ancient tea plants samples and 4 control samples)were amplified by using 10 ISSR primers with good amplification.A total of 67 bands were amplified,and the amplified bands were between 100 and 2000 bp,of which 64 were polymorphic,accounting for 95.5 percent,indicating that ancient tea tree populations genomic DNA with high polymorphism.Similarity coefficient between the test material is from 0.35 to 0.85,with an average of 0.60.UPGMA method was used for cluster analysis.The samples were divided into 10 groups at 0.60.Among them,the genetic distances between the six single plants and other single plants are relatively large,so their genetic backgrounds are different.However,most of the individual plants are clustered closer together,their genetic background is relatively consistent,and with close genetic relationships.The clusters of ancient trees in three regions(numbered "T",numbered "D",and numbered "P")are more concentrated,indicating that the ancient tea trees in these three regions are genetically concentrated and stable.It was also found that some individual plants were more distributed and showed rich genetic diversity.2.Biochemical component analysis: Through the analysis of the main biochemical components of 36 strains of ancient tea plant in two years and three seasons,the average water extract content was found to be 46.31%,the average tea polyphenols was 30.39%,the total free amino acid content was 3.88%,the average theobromine,caffeine and gallic acid content was 0.71%,4.97%,and 0.15%,the average total catechin was 25.13%,and the average total ester catechin was 20.25%.Overall,the ancient tea tree resources in Wangdong Township of Liuzhou have high water extract content,free amino acid content,caffeine content,alkaloid content,EGCG content,and suitable tea polyphenol content,which is an excellent local characteristic resource.The analysis of specific differences revealed that the highest variation coefficient of ancient tea tree resources was 10.66%,followed by amino acids,which was 10.05%,and the smallest was 2.92% of water extracts.In the total catechin composition,the mean values of the components were EGC(2.68%),DL-C(1.49%),EC(0.70%),EGCG(9.34%),GCG(8.11%),and EGC(2.79%).The differences in the content of catechins in tea plants were larger,the coefficient of variation of non-ester catechins was higher than that of ester catechins,and the greatest coefficient of variation was D,L-C,which reached 38.26%.15 chemical components were analyzed for principal components.It was found that the contribution rate of the first five principal components reached 81.644%.These five principal(P1?P2?P3?P4?P5)components can sum up the characteristics of the entire resource traits.The analysis of changes between seasons showed that,the content of amino acids in spring was slightly higher than that in summer,while the content of water extract and tea polyphenols was higher in summer than in spring.The overall results show that the fresh leaves of ancient tea trees in the spring and summer seasons contain high water extracts,high free amino acids,high gallic acid content,high EGCG content and high tea polyphenol content,indicating that the fresh leaves of ancient tea trees have high utilization value in spring and summer.Six strains(P26,T06,T09,T20,T29,D10)with excellent biochemical components were selected from the ancient tea trees which with high water extract content,amino acid and tea polyphenols appropriate.At the same time selected a batch of specific plants.3.Amino composition analysis:Among the tested materials,18 kinds of amino acids were complete,high content and diversity,also with large coefficient of variation.The top five of content were theanine(19.09 mg/g);histidine(0.95 mg/g)methionine(0.91 mg/g);and aspartic acid(0.88 mg/g);glutamic acid(0.83 mg/g);these five amino acid components accounted for 80% of the total amino acids.Significant analysis demonstrated that there was a very significant correlation between theanine content and total amino acid content,also with there is a very significant correlation between a large number of amino acid contents.A batch of individuals with high theanine content was selected: T08(30.29 mg/g),T15(28.45 mg/g),T09(27.31 mg/g),T14(25.48 mg/g),T25(24.55 mg/g),P26(24.52 mg/g).4.Appropriateness analysis: The sensory evaluation showed that the green tea made by ancient tree has the characteristics of high aroma and good taste,and the black tea made by ancient tree with high and long fragrance,tasted sweet,and with bright red soup,bright leaf bottom.From the analysis and comparison of the main contained biochemical components,the ancient tea has high water extract,amino acid,caffeine and moderate tea polyphenol content,indicating that the ancient tea tree has great potential for development. |
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