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| Changes in kinetic parameters of phenanthrene uptake by wheat roots under different conditions |
| Received:March 01, 2016 |
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| KeyWord:uptake kinetics;phenanthrene;wheat;temperature;pH;seedling age |
| Author Name | Affiliation | E-mail | | LU Shou-kun | College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095, China | | | YANG Qing-qing | College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095, China | | | WANG Hong-ju | College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095, China | | | LI Jin-feng | College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095, China | | | SHEN Yu | College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095, China | | | ZHAN Xin-hua | College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095, China | xhzhan@njau.edu.cn |
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| Abstract: |
| 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℃, Km and Vmax increased with an increase in temperature. The relationship between Km or Vmax and temperature was well fitted with an exponential function. When the temperature was higher than 35℃, Km and Vmax decreased. At pH of 3.00~8.00, the affinity of phenanthrene to wheat root carrier proteins decreased with increasing pH. The Vmax was greatest at pH 5.50. However, the affinity of phenanthrene to wheat root carriers increased with seedling growth, but Vmax was 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. |
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