Distribution and Phytotoxicity of Polycyclic Aromatic

Polycyclic aromatic hydrocarbons are a group of important organic pollutants and should be concerned. General sources of PAHs are contamination of petroleum hydrocarbons and incomplete combusion of organic compounds. The recalcitrance of these compounds depends on the arrangment of benzene rings and their molecular weight. Besides they are carcinogenic and mutagenic to animals PAHs show several toxicity to plant such as decreasing shoot and root growth and photosynthetic rate. PAHs are toxic to plant at molecular level such as increasing oxidation pressure and decreasing gene expression of cell wall-loosening protein expansion. Photooxidized PAHs showed higher toxicity to plant than parent compounds. Plant species and some environmental factors such as soil pH affect to PAHs phytotoxicity. Phytotoxiciy of Polycyclic aromatic hydrocarbons to crop plant growing in Polycyclic aromatic hydrocarboncontaminated soil is an important environmental concern