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báo cáo khoa học: " Accumulation of phenanthrene by roots of intact wheat (Triticum acstivnm L.) seedlings: passive or active uptake?"

Tuyển tập báo cáo các nghiên cứu khoa học quốc tế ngành y học dành cho các bạn tham khảo đề tài: Accumulation of phenanthrene by roots of intact wheat (Triticum acstivnm L.) seedlings: passive or active uptake? | Zhan et al. BMC Plant Biology 2010 10 52 http www.biomedcentral.com 1471-2229 10 52 BMC Plant Biology RESEARCH ARTICLE Open Access Accu mulation of phenanthrene by roots of intact wheat Triticum acstivnm L. seedlings passive or active uptake Xin-Hua Zhan 1 Heng-Liang Ma1 Li-Xiang Zhou 1 Jian-Ru Liang1 Ting-Hui Jiang1 2 and Guo-Hua Xu1 Abstract Background Polycyclic aromatic hydrocarbons PAHs are of particular concern due to their hydrophobic recalcitrant persistent potentially carcinogenic mutagenic and toxic properties and their ubiquitous occurrence in the environment. Most of the PAHs in the environment are present in surface soil. Plants grown in PAH-contaminated soils or water can become contaminated with PAHs because of their uptake. Therefore they may threaten human and animal health. However the mechanism for PAHs uptake by crop roots is little understood. It is important to understand exactly how PAHs are transported into the plant root system and into the human food chain since it is beneficial in governing crop contamination by PAHs remedying soils or waters polluted by PAHs with plants and modeling potential uptake for risk assessment. Results The possibility that plant roots may take up phenanthrene PHE a representative of PAHs via active process was investigated using intact wheat Triticum acstivnm L. seedlings in a series of hydroponic experiments. The time course for PHE uptake into wheat roots grown in Hoagland solution containing 5.62 pM PHE for 36 h could be separated into two periods a fast uptake process during the initial 2 h and a slow uptake component thereafter. Concentration-dependent PHE uptake was characterized by a smooth saturable curve with an apparent Km of 23.7 pM and a l max of 208 nmol g-1 fresh weight h-1 suggesting a carrier-mediated uptake system. Competition between PHE and naphthalene for their uptake by the roots further supported the carrier-mediated uptake system. Low temperature and 2 4-dinitrophenol DNP could inhibit PHE