The effects of cadmium sulfate on cadmium accumulation and phytochelatin synthesis were investigated in leaf, stem and root tissues of two sunflower cultivars, cadmium tolerant Helianthus annum cv. Meriç and sensitive Tarsan 1018. The seedlings were grown for 15 days in Hoagland solution and then exposed to CdSO4 at 150 µM, 200 µM, 250 µM and 300 µM for 4 days. Most cadmium accumulations were determined in the roots of both cultivars on the 2nd and 4th day. The cadmium sensitive cultivar, Tarsan 1018, accumulated more Cd in all tissues compared to the tolerant cultivar. Phytochelatin synthesis was induced by Cd exposure in both cultivars at the 2nd and 4th day. Higher phytochelatin accumulation was observed in root tissues of Tarsan 1018 cultivar at the 4 th day. Phytochelatin levels in all tissues of both cultivars increased depending on Cd accumulation in those tissues
