中文摘要：

为揭示植物根系吸收多环芳烃（PAHs）的生物化学机制,建立疏水性有机污染物的植物根系吸收数学模型,并为科学预测农作物的污染风险提供依据,采用水培方法研究了不同温度、pH、培养时间以及地上部分去除与否条件下小麦根系吸收菲的动力学参数的变化规律。结果表明,在15~30℃范围内,小麦根系菲吸收的Km（米氏常数）、Vmax（最大吸收速率）随着温度的升高而增大,Km、Vmax与温度的关系满足指数函数关系;当温度达到35℃时,Km和Vmax的值均出现了下降;在pH为3.00~8.00时,小麦根系对菲的亲和力随着pH的升高而降低,pH为5.50时Vmax达到最大值;幼苗期小麦根系对菲的亲和力随着苗龄的增加而增大,Vmax随着苗龄的增加而减小;活体根和离体根的菲吸收动力学差异不明显。研究显示,温度、pH、苗龄均能显著影响小麦根系菲吸收的动力学参数。

英文摘要：

Polycyclic aromatic hydrocarbons（PAHs）are ubiquitous contaminants in the environment. Dietary intake of plant-based foods has become a major contribution to the total exposure of PAHs for the human beings. Because of well-documented carcinogenicity, mutagenicity and toxicity of PAHs to humans, it is of great importance to establish a model of PAH uptake by crop roots for health risk assessments of human exposure to PAHs. However, little information is available regarding such models of PAH uptake by crop roots including active transport. Here hydroponic experiments were employed to investigate the kinetic parameters of phenanthrene uptake by wheat roots under different temperatures, pHs, and wheat seedling ages. In a temperature range of 15 ~30 ℃, Kmand Vmaxincreased with an increase in temperature. The relationship between Kmor Vmaxand temperature was well fitted with an exponential function. When the temperature was higher than 35 ℃, Kmand Vmaxdecreased. At pH of 3.00~8.00, the affinity of phenanthrene to wheat root carrier proteins decreased with increasing pH. The Vmaxwas greatest at pH 5.50. However, the affinity of phenanthrene to wheat root carriers increased with seedling growth,but Vmaxwas just reverse. There was no significant difference in uptake kinetics between in vivo and in vitro wheat roots. Therefore, it was concluded that temperature, pH and seedling age have remarkable effects on kinetic parameters of phenanthrene uptake by wheat roots. Our results provide insights into both biochemical mechanisms underlying PAH uptake by plant roots and data for establishing model for PAH uptake by crop roots.