Accumulation And Distribution Of Fluoride/Aluminium In Subcellular Of Tea Leaves And Roots

Tea plant is a high fluoride/aluminium-accumulated and tolerated plant. Morethan90%of fluoride/aluminium exsited in the old leves, which contain thousands ofmilligram fluride per kilogram tea in dry weight? Taking too much fluoride/aluminiumwill threaten human health. Investigation of accumulation and translocation offluoride/aluminium in different tea varieties will provide useful data for regulating theaccumulation of fluoride/aluminium in tea plant. Understanding the distribution offluoride/aluminium in its intracellular distribution pattern will help in assigning its effectson cellular activities and should also be valuable in defining its possible biochemical roles.In this paper, characteristics of accumulation and translocation of fluoride in differenttea varieties at soil and solution culture were investigated by the principal componentanalysis and cluster analysis methods. Differential centrifugation method was conducted toexplore the distribution characteristics of fluoride in cell component of tea plant(Shuchazao) young leaves and roots. Purified vacuoles were also isolated from tea leavesprotoplasts, and the contents and distribution of fluoride and aluminium in vacuoles werealso investigated. Results are as follows:1. The fluoride contents in different parts of tea plants were in the order of old leaf(243.59mg/kg)>young leaf (101.60mg/kg)>root (7.53mg/kg) and stem (7.87mg/kg).Fluoride contents in leaves varied significantly with the different cultivars (P<0.05).Principal component and cluster analysis results showed that: different tea varieties couldbe clustered into4groups: Wuniuzao cultivar was grouped into high accumulation and hightranslocation type; Fuzao-2-hao cultivar was grouped into low accumulation and lowtranslocation type; Longjing43and Pingyangzao cultivars were grouped into mediumaccumulation and low translocation type; Zhenong113and other tea varieties weregrouped into medium accumulation and medium translocation type.2. Subcellular fraction of F-containing tissues showed that52.34%and71.78%offluoride were localized in cytoplasmic fraction in roots and leaves, and the fluoridecontents in1g fresh roots and leaves were11.07μg and21.36μg respectively. Vacuolesfrom tea leaves contained97.98%of the total intracellular fluoride, which meansvacuoles is the main organelle storing fluoride in tea leaves.3. The contents of aluminium in in tea roots and leaves were108.05and160.19μg/g fresh weight, which accounting for69.83%and75.20%of total aluminiumwere bound to cell wall in tea root and leaves respectively, and the contents were 108.05and160.19μg/g fresh weight. When pectin was removed from tea root cell wall, thealuminium levels was declined from114.06μg/g to52.14μg/g, and more than half ofaluminium (54.29%) was lost. This result indicated that aluminium mainly existed inpectin of cell wall. Vacuoles from tea leaves contained88.29%of the total intracellularaluminium, which means aluminium mainly stored in vacuoles in tea leaves.