Induction of Oxidative Stress and Anatomical Changes by Polycyclic Aromatic Hydrocarbons in Medicago sativa L.

In this study effect of anthracene on germination, anatomy and oxidative stress in Medicagosati-va was evaluated. Seed germination, length and weight of seedlings were measured after seven days of treat-ment (2 and 4 mmol L-1). After twelve days, anatomical changes and activity of Superoxide Dismutase, Poly-phenol Oxidase, Ascorbate Peroxidase, Glutathione Transferase, Soluble Peroxidase, Malondialdehyde in shoots and roots, as well as chlorophyll content of aerial parts, were determined. Also, morphological changes during the growth in complete plants were studied. The results showed that, anthracene had no significant ef-fect on seed germination, but reduced the length of seedlings and the weight of them. The activity of mentioned enzymes in the shoot and often in the roots, in 4 mmol L-1 anthracene significantly was increased compared to the control plants. Anthracene treatment decreased significantly Malondialdehyde levels in shoot, while it in-creased significantly in roots and this treatment had no significant effect on chlorophyll a and b contents. Peri-derm diameter increased in treated roots and xylem extent reduced in treated shoots. It seems that the low water solubility of anthracene, also, the low sensitivity of alfalfa to PAHs, partially stabilize the plant to low concen-tration of Anthracene.