Study On Bioremediation Effects Of Lead, Nickel From Aqueous Solutions By Gracilaria Tenuistipitata And Its Physiological Response

In recent years, the algae is widely focused considering as the ideal materials of biological repairation. Gracilaria ,belonging to tropical or temperate, subtropical algae, are distributed in China's coastal regions. Gracilaria is the type of strong adaptability and fast growth, high yield, simple cultivation method and promotion easily. The experiment will choose large algae--Gracilaria(Gracilaria tenuistipitata Var. liui Zhang et Xia) as research materials ,Pb(II), Ni(II) heavy metal ions as pollution factor,through the indoor static simulation experiments,from different angles,comprehensive utilization of plasma emission spectrometer, Speeding centrifuges, differential centrifuges and other experimental instruments studing on the Gracilaria powder adsorption of Pb(II), Ni(II) ions of heavy metals and equilibrium model; the short-term effect of removing Pb(II), Ni(II) heavy metal ions in a single heavy metal ions Pb(II), Nil II) pollution stress for Gracilaria alive; the accumulation of different heavy metal ions, the distribution of heavy metal ions of the quality of Gracilaria, a total of Gracilaria and quality of functional cell. preliminary evaluation of Gracilaria on the purifying effect of heavy metals. To further explore the physiological and biochemical mechaNi(II)sms of Gracilaria absorption of heavy metals and lay the foundation for practical applications of heavy metal pollution in the environment.In the adsorption experiments of Gracilaria algae powder, we found that, pH values was in the 2.3-5.2 range, the lower pH value, the smaller algae Gracilaria powde on the absorption of Pb(II) and Ni(II) heavy metal ions, having a greater absorption capacity in the 5.2-6.8 of pH values. In this condition, Water temperature at 20℃, pH value of 6.8, the algae Gracilaria powder were up to 65.5 and 45.2 mg/g on adsorption capacity of Pb(II) and Ni(II) ion.Ni(II) , Pb(II) heavy metal ions have a certain impact on the growth of Gracilaria, Pb(II) have more serious poisoNi(II)ng than Ni(II). In sewage environment of a single heavy metal, the cumulative removal of metal ions is Pb(II)> Ni(II), at low concentrations (0.05 mg/L), after 1 d's biosorption, the removal of Pb(II) and Ni(II) are up to the rate of more than 90 percent, It shows that Gracilaria of low concentrations of Pb(II) and Ni(II) have a good effect on bioremediation in the short term. The reserves of Ni(II),Pb(II) heavy metals in Gracilaria are Pb(II)> Ni(II);the reserves of Pb(II) and Ni(II) heavy metal ions in Gracilaria are 985.64 ug/gFW and 649.5ug/gFW when Pb(II) and Ni(II) concentration are 5 mg/L. Ni(II),Pb(II) heavy metal ions are mainly distributed in the quality of Gracilaria body, the cytoplasm of the function cells, the order of Pb(II) and Ni(II) distribution are chloroplast>ribosomal> mitochondria> nucleus.In addition, we study Gracilaria following 3 d and 6 d exposure to different concentrations of Pb(II),respectly, the Changes of the content of red algae, chlorophyll, protein, phycobiliprotein (including phycoerythrin, blue algae Protein and other phycocyaNi(II)n) of Gracilaria species, and the effect of water content of Pb(II) and Ni(II) on Gracilaria superoxide dismutase(SOD), peroxidase(POD),glutathione reductase(GR), a glutathione-Oxide(GPX), glutathione(GSH),MDA(MDA),proline content. The results showed that the growth of Gracilaria, both physiological and biochemical indicators show a certain degree of change in the law in Pb(II), Ni(II) heavy metal stress.Through the observations on production of paraffin section, Pb(II) have more serious effct than Ni(II) on the extent of the damage cells of Gracilaria. High concentration (5 mg/L) of the Pb(II) have more serious damage cells, peripheral cells sigNi(II)ficantly reduce the number of layers, cell Rupture is relatively serious.