Characterization Of Pb After Accumulated And Localized In Tissues And Cells Of Hydroponic Tea

Quality safe of tea was the important research item in developing the tea industry and enhancing the competition of international tea market. The heavy metal was one of the four factors which effected tea quality safe, lead in tea, extensive pollute source, accumulated characterization of lead in tea, localization lead in tissues and cells in tea became hot research item. This article use hydroponic tea, plenty use the theory and research method of tea cultivation, botany, plant physiology and plant anatomy, systematically study accumulation and localization of lead in organs, tissues and cells in hydroponic tea, and gained a main fruit as follows:(1) We first used the nourishment liquid contained different lead to hydroponic tea for35days, then measured the lead content in roots, stems and leaves of tea by the atom absorbs spectrophotometer (AAS), and discuss the accumulation rate and distribution rate of lead in each organ of hydroponic tea, results showed:lead content in each organ of tea was roots> stems> leaves; Lead accumulation rate reached the maximum432939%,315326%,106652%when the concentration of lead in nourishment liquid was2500mg/L,2500mg/L,2000mg/L, while the maximum distribution rate was93.32%,54.76%,0.5%, when the concentration of lead in nourishment liquid was150mg/L,0mg/L,0mg/L respectivelyResults of observation showed that the hydroponic tea was not appeared victimize symptom when the concentration of lead in nourishment liquid was lower than800mg/L, while the roots of tea changed to clarity from white, and became brown and some became black, and the nerve changed to brown from green, the speckle of leaves ware larger, and leaves ware withered and shed off.(2) Separated each section of roots, stems and leaves cells of tea by technology of separation of section of plant cell, then measured lead content of each section by AAS, discussed the distribution rate of lead in the cell of hydroponic tea, results showed:the distribution rate of lead in cell wall of roots, stems and leaves was83.19%,67.72%,61.28%; and in the membrane of roots, stems and leaves was10.41%,19.23%,14.21%; and in the cell organ was5.27%,11.09%,23.52; in the cell nucleus was5.27%,11.09%,23.52respectively. (3) Coloration of stems frozen slice by EBT, Congo red and TPPS4respectively, results showed:the color of cell case, forming layer and secondary xylem differentiation were changed gradually from brown to lavender, purple red and purple with increasing of lead concentration in the nourishment liquid when colored by EBT, while the color of promyelocytic changed deeper, and parenchyma, forming layer and secondary xylem differentiation changed to yellow and brown when colored by TPPS4, but the color on stems almost had no change while colored by Congo red.Coloration the roots, stems and leaves slices by EBT and stationn the dye area, results showed:the maximum dye area percentage were dictyostele(15.78%)>cell case(12.4%)> cortex(3.5%) in roots; differentiation(23.54%)>forming layer(21.83%)>cell case(19.76%)> phloem(18.46%)> cortex(3.96%)> dictyostele(2.62%) in stems; phloem(25.82%)> forming layer(18.08%)> cell case(16.59%)> differentiation(12.76%)> palisade tissue(11.18%)> spongy tissue(5.43%)(4) Ultra-structure localization of lead in roots, stems and leaves cells in tea by SEM-EDS and TEM-EDS, results showed:the maximum accounts of lead in roots, stems, leaves of hydroponic tea in lead concentration1600mg/L nourishment liquid were1873,721and714, and was213in leaves of tea planted by distilled water. While the maximum accounts of K were618,155,122and98respectively. The lead on cell wall of roots were equal and quality, while the quality of lead on plasma, cytoplasm and vacuole membrane were no more; Lead on cell wall of stems were numerals and small, and had little on plasma, vacuole membrane and chloroplast; lead on leaves were mainly on plasma and vacuole membrane, there were only a little on the cell wall of leaves.