The beneficial root endophytes play a crucial impact in improving plant performance, and participate in enhancing phytoremediation efficiency of host in metal-polluted sites. This experiment investigated the influence of root endophyte fungus Serendipita indica on lead (Pb) accumulation and translocation, some physiological attributes, and antioxidant system of leaf in Carthamus tinctorius L. (safflower) cv. Sina in soil contaminated with different levels Pb (0, 400, 800 and 1200 mg Pb/kg soil). By increasing Pb levels in soil, Pb uptake by root, and Pb accumulation in root and shoot were significantly elevated. A significant increase on Pb accumulation in root and a significant reduction on shoot Pb amount were observed under fungal symbiosis. Also, S. indica-inoculated plants had lower translocation factor (TF) and bioaccumulation factor of Pb in shoot (BFS), whereas higher bioaccumulation factor of Pb in root (BFR), in compare to non-inoculated ones. Presence of S. indica yielded in greater growth parameters, photosynthetic pigments, chlorophyll fluorescence parameters, and antioxidant enzymes activities of CAT, APX and SOD, under all levels Pb in soil. We suggest the consideration of this endophyte for fungus-assisted phyto-stabilization/immobilization of Pb in host roots. Also, we concluded that S. indica mediated different tolerance strategies to mitigate Pb toxicity and higher performance of safflower.
