The Adsorption And Accumulation Character Of Lead And Copper In Tea Plants Cultured In Hydroponics And The Way Of Controlling

Lead (Pb) and copper (Cu) can be accumulated in tea plants. They can be absorbed by the two ways of roots and leaves of tea plants. Many researches surveyed the Pb and Cu content in tea plants and fields, the influence of Pb and Cu on the growth of tea plants and the Pb and Cu accumulation character of tea plants. However, for the reason of the complex environment, it is not certain whether these results are because of the physiology character of tea plants itself. As to control the Pb and Cu content in tea from the material part on, it is very necessary to research the Pb and Cu accumulation character in tea plants and find the proper planting way to control. As consequence, the paper did the researches. The theory and methods of Cultivation of tea plant, plant physiology and plant nutrition were used to investigate the Pb and Cu accumulation character in tea plants, the influence factors and the way to control.The hydroponics system was used in the paper, to investigate (1) the Pb accumulation character in tea plants; (2)the influence of N,P,Ca,Al on Pb accumulation; (3) the Cu accumulation character in tea plants; (2)the influence of N,P,Ca,Al on Cu accumulation. The main results are as follow:(1) Cultured in 300mg/L Pb solution for 35d, Pb content in the fractions increased significantly, and the most Pb content in the fractions are leaves 207.07 mg/kg, top stem 170.29mg/kg, middle stem 168.83mg/kg, bottom stem1089.75mg/kg and roots 2.90×104mg/kg. Cultured in 150-3000mg/L Pb solution and cultured in stilled water with Pb solution of the same concentration foliar on the leaves, the results showed that, the fraction where is polluted accumulate the most, the most Pb content in leaves and roots are:cultured in Pb solution, leaves 551.10 mg/kg and roots 7.80×104mg/kg; cultured in stilled water with Pb solution foliar on the leaves, leaves 1.03×104 mg/kg, roots 7998.90 mg/kg. Pb was transported through stems and accumulated mostly in leaves and roots. Tea plants can strongly tolerate the suffering of Pb.(2) N,P,Ca,Al ion were added into 300mg/L Pb solution and N solution foliar on the leaves, all the ions significantly influence the Pb accumulation:low concentration of N solution increased the growth of tea plants, and increased Pb concentration; high concentration of N solution decreased the Pb concentration but also decreased the growth of tea plants. N solution foliar on tea leaves, the tea plants grew well, low concentration of N solution decreased the Pb content, and the high concentration of N solution increased the Pb content. P can significantly decrease the accumulation of Pb in tea plants. Certain concentration of Ca ion can decrease the Pb accumulation, but too high concentration would influence the growth of tea plants. Al ion can significantly decrease the accumulation. The largest decreasing rate of the ions are N 14.43%, foliar N 21.90%, P 57.69%, Al 67.21% and Ca 62.25%.(3) Cultured in 80mg/L Cu solution for 21-40d, Cu content in the fraction of the tea plants increased significantly. The most Cu concentration in the fractions are leaves 356.94mg/kg, top stem 40.53 mg/kg, middle stem 39.01 mg/kg, bottom stem 51.64 mg/kg and roots 1951.67mg/kg. Cultured in 100-1200mg/L Cu solution and cultured in stilled water with Cu solution of the same concentration foliar on the leaves, the results showed that, Cu accumulated mostly in the roots, and then leaves; the most Cu content in the two fractions are:in Cu solution, leaves 1297.60mg/kg and roots 3387.43 mg/kg; in stilled water, leaves 2953.18 mg/kg and roots 4931.76 mg/kg.(4) N,P,Ca,Al ion were added into 80mg/L Cu solution and N solution foliar on the leaves, all the ions significantly influence the Cu accumulation:N solution foliar on tea leaves, the tea plants grew well, low concentration of N solution increased the Cu content in tea plants, and the high concentration of N solution decreased the Cu content. P can significantly decrease the accumulation of Cu in tea plants. Certain concentration of Ca ion can decrease the Pb accumulation, and increase the accumulation of Cu in roots; however, too high concentration would influence the growth of tea plants. Al ion can significantly decrease the accumulation. The largest decreasing rate of the ions are N 31.43%, foliar N 55.31%, P 61.76%, Al 71.78% and Ca 64.71%。All the results were aimed at build a theory to control the accumulation of Pb and Cu in tea plants from the material part on.