| According to tea industry, the tea quality-and-safety has been an important issue to improve the comprehensive strengthen and to enhance the international competitiveness. Fluorine (F) content in the brick tea is regarded as a significant part of tea quality-and-safety. In order to analyze the distribution and location of F in the body tissue cells of tea bushes, it should be taken into consideration of the method of its determination, analysis of its origin, and detection of its source.Fully used phytology, tea culture, tea bio-chemistry, phytophysiology, and edaphology et al. as an instruction, this paper took advantages of tea inspection, instrumental analysis, statistic analysis, gradient centrifugation, plant tissue frozen section, and microscopic dyeing technology to compare the methods of F content determinations and the origin of high F content in tea brick, and to analyze the the distribution and location of F in the body tissue cells.The results were as follows:(1) Determination of F content in green tea and dark tea by the methods of ISE and SP. The differences were significant between the two methods in both green tea(F=189.86**> F0.01(1,59)=7.27) and dark tea(F=60.39**>F0.01(1,59)=7.27). The linearity range were lgCF- — 0.8～0.8 (ISE) and 0～0.3mg/ml(SP). The standard deviation were 3.37(ISE) and 4.30(SP). Both of the above results were comparable reliable. In addition, the average adding standard recovery were 98.4% (ISE) and 99.7% (SP) and this result was comparable accurate. The detection limit was 0.07mg/L (ISE) and O.lmg/L (SP). In comprehensive comparison of the two methods, both of them could accurately determine the F content in tea samples, and ISE method should be used to determine high concentration of F as well as SP in low concentration.Then TISAB buffer, contents of samples, electrode, filter condition and rotate speed were controlled to determine and analyze the effect on the F content of brick tea in different experimental conditions. The results showed that the most accuracy presented in such conditions as TISAB(GB),0.15g samples, new electrode, qualitative medium filter paper and under the high speed.(2) Tea tree is a plant what F could easily accumulate in, and the more tender fresh leaf is, the lower F content will be. According to the material tenderness, the F content showed as that:Yiyasansiye<Yiyaqibaye<climax leaves, and A>B>C>D>E>F>G the different producing area F contents in brick tea. Amount all the tea ingredients, those used to make Zuozhuang tea、Maozhuang tea and Jinyu tea showed the highest F content, followed by those used to make Qingzhuang tea and Maozhuang tea et al., and there was no such a trend in F and G.(3) The leaves were the parts where F mostly accumulate, containing 91.88% of accumulating F. The F content in the climax leaves showed as that:mature leaves> Hongtailvgeng new treetop>Lvgeng treetop>branch root>branch spot>major jib> major root. There was a positive correlation between F content of climax leaves and water soluble F content in tea garden(F=6.637**>F0.05(1,29)=4.18), however, no significant relationship appeared in new leaves and water soluble F content. Fertilizer used by tea garden increased the F content in the soil, therefore improved the F content in tea trees and aggravated the F accumulation. Moreover, tea has less spraying of pesticides, but Fluoride could increased in the leaves by entering into the ports of them,(4) F contents in the root, stem and leaf of hydroponic tea tree increased while the NaF concentration decreased. F contents of the subcellular components in each parts showed as followed:cell nucleus>organelles sparing the nucleus>cytoderm and residue> soluble substance and cell membrane (leaf); cell nucleus>organelles sparing the nucleu> soluble substance and cell membrane>cytoderm and residue (stem); cell nucleus>cytoderm and residue>organelles sparing the nucleu> soluble substance and cell membrane(root). All the above three analysis was in line with the binomial equations. The distribution of F absorbed by each subcellular component of hydroponic tea was different, that the highest amount was in the nucleus, then in rganelles sparing the nucleu, and the lowest in soluble substance and cell membrane.(5) Using Alizarin complexone as specific stain, different concentration levels of hydroponic tea including the root, stem and leaf were dyed to observed and taken photos by optical microscope. The results showed that in the root tissue of hydroponic tea the most F accumulated in the phloem and epidermis, then the cambium, and in its root and tender bine the trend appeared respectively that:stele>epidermis (root), and xylem and phloem> epidermis (tender bine). Dyeing percentage statistics of leaf, stem, and leaf transaction which were fostered by different NaF and then dyed by Alizarin complexone showed that in hydroponic tea F mainly accumulated in the phloem(28.43%), epidermis (21.43) and cambium(14.44) of the leaves, the root stele(27.96%) and skin(18.08%), and the xylem(24.65%), phloem(19.45%), epidermis(17.73%) and cambium(10.56%). |
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