Effects of Salinity Levels on Heavy Metals (Cd, Pb and Ni ) Absorption by Sunflower and Sudangrass Plants

Large parts of Iran have arid and semiarid regions and one of the important problems of these regions is soil and water salinity. Also heavy metal enters in the soil through the various ways such as: sewage sludge and pesticides. As a result salinity and heavy metals concentration in soil are two major problems in parts of arid and semiarid regions. The aim of this research was studying the effect of different salinity levels on availability of some heavy metals. Experiments were conducted in a completely randomized design with factorial layout in the greenhouse of Research Center of Agriculture and Natural Resources, Isfahan, Iran. The factors include heavy metals in 3 levels (Cd, Pb, Ni), salinity in 3 levels (EC (dS/m): 2, 7, 12) and plant in two kinds (Sunflower and Sudangrass) with three replications. The result of soil analysis showed that availability amount of heavy metal (Cd, Pb, Ni) was increased in soil with increasing of salinity. The result of plant analysis showed that there was corresponding increase in concentration of absorbed Cd in all parts (root, stem, leaf) of Sunflower and Sudangrass with increasing salinity. The amount of Pb with regard to low mobility in plant and soil was equal to zero in stem and leaf of two plants, but it was increased in root of two plants with increasing of salinity. Due to high mobility of Ni in plant tissues was noticeable the amount of absorbed Ni in root, stem and leaf of both plants. But the amounts of its in root of Sudangrass were much more than root of Sunflower.