| Tea is one of the three most popular drinks in the world and consumptioned by2/3of the world’s population.Not only contain the biochemical composition of caffeine, catechin, tea polysaccharide, beneficial to human body but also contains trace elements involved in the life activities of Cu, Zn, Cr, Co, Ni, Sr etc in tea.Although the content of trace element in the plant is small,but it is indispensable to study the physiological process of tea, the content of mineral element is an important research in tea study. For decades, researchers have made many achievements from tea plant nutrition, health tea, tea, in the tea garden soil. It contains many kinds of mineral elements and the content of various elements have some differences in the same areas and among different regions.But in the specific region, the content variation coefficient of trace element in soil of tea garden is small.That is to say the content of most trace element is stable but affected by the growth of tea geographical environment, climatic conditions, tea varieties, production engineering and other factors.China is a country with a lot of tea and tea producing regions.Guizhou is one of the most important tea producing areas where is located in the southeas of south-west areas and in the Yunnan Guizhou Plateau east slope. Its geographic coordinates for east longitude103°36’-109°35’, north latitude24°37’-29°13’.There are667000hm2soil suitable for tea area. Since2007, with the support of the government of Guizhou Province,it’s tea garden had made great development that already ranks second in the country. This study collected from different tea gardens in Guizhou Zunyi, Anshun, Tongren, Qiannan four major tea area of24sampling points in spring, summer, autumn three seasons tea like72. The samples were treated by dry ashing and microwave digestion, and we detect trace elements and rare earth elements in the samples by ICP-MS, and analysis data by using SPSS statistical analysis software. According to the different regions of the same season tea sample analysis, it showed that the types of elements contained in four regions in tea sample are the same basically, but there were significant differences in the content. Due to the different regions, different elements in tea sample showed a different trend. In the Guizhou tea samples, the content of Zn、Cu is higher than other samples and the content of Co is lower than other samples, other content i s basically moderate. In this study, the content of Cu is less than30mg/kg and the content of Cr、As is in accordance with the standard of organic tea garden, which reflects that the Guizhou area ecological tea garden is good and it i s suitable for planting green tea and organic tea.Analysis of element correlation showed there were significant correlations between elements. For example, there was a positive correlation between Cr and As, Cd, but were negatively related to Zn, Sb. Co and Ni had negatively related to Zn and Sr. That reflects the synergy and antagonism between elements, which show great effects on guiding the tea garden fertilization and improving fertilizer use efficiency and quality of tea. Principal component analysis that, the contribution rate of different elements is not the same, the contribution rate of rare earth element is higher than others. Cluster analysis showed that tea samples among different regions with similar characteristics can better together as a class, which can determine the geographical protection mechanism of tea according to the area. The different seasons of the tea samples were not clustered into one group, so the tea sample segmentation is difficult to achieve using seasonal characteristics.It was discovered that the content of rare earth will increase but slightly from the research of green tea processing.The results of significant difference analysis show that processing process is not the main factor of increasing rare earth content in tea. According to the detection analysis of different tenderness in tea it was discovered that the difference of rare earth content between different tenderness in tea is very large. During the same period in the same tea picking the rare earth content of a four-leaf bud is the as much as2times higher than the bud. According to the detection analysis on different varieties of raw materials of tea, results show that there are some differences between different varieties of tea plant on enrichment ability of rare earth, which provides theoretical support on according to the tea planting varieties to determine the types of fertilizers.The above results showed:first, the ecological soundness of Guizhou tea garden ecology is fitting the development of suitable green tea, organic tea.Second, Guizhou area of trace elements in tea are in the standard in the law of the state, and the level of quality and safety is higher.Third, the content of trace elements in different varieties of tea leaves are different. In addition, there are differences in the trace elements content of tea sample in different seasons, but the difference was not significant. Therefore, in a certain range, the trace elements content of tea to determine the origin of tea, but can’t distinguish the seasonal picking tea. |
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