Proton-coupled cotransporter involves phenanthrene xylem loading in roots

The uptake and translocation of polycyclic aromatic hydrocarbons (PAHs) by staple crops have gained much attention. However, the mechanism on phenanthrene xylem loading across plasma membrane is still unclear. In this study, we investigated the concentration dependence of phenanthrene xylem loading...
Ausführliche Beschreibung

The uptake and translocation of polycyclic aromatic hydrocarbons (PAHs) by staple crops have gained much attention. However, the mechanism on phenanthrene xylem loading across plasma membrane is still unclear. In this study, we investigated the concentration dependence of phenanthrene xylem loading and the relationship between phenanthrene concentration and xylem sap pH. The impacts of metabolic inhibitor, temperature, and dissolved oxygen on phenanthrene concentration in xylem sap were observed as well. The Michaelis-Menten equation fits phenanthrene xylem loading across parenchyma cell membrane well and xylem sap pH decreases with the increase in treated phenanthrene concentration. Metabolic inhibitor, low temperature and low dissolved oxygen can suppress phenanthrene loading into xylem sap. The inhibitory rate of sodium vanadate on xylem sap phenanthrene is between 19.76% and 25.82%. Low temperature reduces phenanthrene concentration in xylem sap by 86.68%. Hypoxia (2 mg L−1) inhibits phenanthrene loading into xylem by 78.67%. Therefore, it is indicated that H+/phenanthrene cotransporter is implicated in phenanthrene loading into xylem. Our work offers a valuable model to understand the mechanism of PAH loading into xylem. Ausführliche Beschreibung