Effect Of Carbohydrates And Lipids On Uptake Of Polycyclic Aromatic Hydrocarbons By Ryegrass

Uptake of organic pollutants by plant was considered as the local partitionsbetween organic components of plants and environment media. Based on the reviewof uptake of organic pollutants by plants, this thesis studied the effect of organiccomponents, such as carbohydrates and lipids, on the plant uptake of hydrophobicorganic pollutants like polycyclic aromatic hydrocarbons(PAHs), and an improvedsorption prediction model was suggested; studied the effect of surfactant on theuptake of PAHs; and observed the translocation and accumulation of PAHs in plantcells using florescence microscopy technology for better understanding the uptakeprocesses and mechanism of organic pollutants by plant, thus guiding safe agriculturalfood production and application of phytoremediation. The main results of this thesisare shown below:(1) Carbohydrates are important accumulation sites for hydrophobic organiccontaminants such as PAHs besides tipids. Although the affinity of PAHs for lipidsappears to be about 1.64 orders of magnitudes higher than that for carbohydrates,sorption of PAHs to carbohydrates could not be neglected because of its predominantweight fraction in plants(about 98 times of lipids for ryegrass root). An improvedsorption prediction model was suggested and the prediction errors with improvedmodel were decreased significantly, and the relative contributions of lipids andcarbohydrates to the sorption of 5 tested PAHs to ryegrass root were 26.69%～35.39%and 64.61%～73.31%, respectively.(2) Surfactant could change the sorption of PAHs to carbohydrates of ryegrassroot, and affect the translocation of PAHs in plant, which may regulate the uptake theuptake of PAHs by plant. Cationic surfactant could enhance the sorption of PAHs tocarbohydrates, which lower the translocation of PAHs in plant. The anionic surfactant,nonionic surfactant and biosurfactant could decrease the sorption of PAHs tocarbohydrates, thus increase the mobility of PAHs in plant and may enhance its uptake by plant. For example, rhamnolipids could significantly enhance the uptake of PAHsby ryegrass. The highest enhancement was 9.07 and 1.98 times of control, whichappear at rhamnolipids concentration of about 0.5 CMC.(3) The translocation and accumulation of PAHs in plant cells could be observeddirectly with fluorescence microscope(FM) and single-photon laser confocalscanning microscope(SPLCSM). Hydrophobic organic pollutants such as pyrenewere translocated with plant via apoplast pathway within cell walls, and cell wall wasthe main storage sites for pyrene in living plant cells.