Effect of Zeolite Application and Seed Priming with Salicylic Acid on Decreasing the Cd Concentration of Inoculated Plant with Piriformospora indica Fungus under Drought Stress

Today, urban management seems necessary to remediate soils contaminated with heavy metals, especially in industrial regions. Thus, this research was done to evaluate the effect of zeolite and seed pre-treatment with salicylic acid on reducing the Cd sorption by ornamental sunflower under drought stress. Treatments (48 treatments) consisted of applying zeolite (0 and 5 % (W/W)) in the Cd (0 and 15 mg Cd (kg soil)-1) polluted soil under cultivation of ornamental sunflower that was inoculated with P.indica in normal and intensive drought stress condition. The plants seeds were pretreated with salicylic acid (0, 0.5 and 1 mM). After 90 days, plants were harvested and atomic absorption spectroscopy (Perkin-Elmer 3030) was used for determining the Pb and Zn concentration. Application of zeolite in the soil significantly decreased and increased the plant Cd and Zn concentration by 11.3 and 14.2%, respectively. Seed priming with salicylic acid at the rate of 1 mM significantly increased the plant Zn and Cd concentration by 12.7 and 14.2%, respectively. In addition, plant inoculation with P.indica significantly decreased the catalase (CAT) and ascorbate peroxidase (APX) enzyme activity which indicate the plant resistance to abiotic stress. However, drought stress had adverse effect on the Cd sorption by plants. Moreover, the CAT and APX enzymes activities were increased. The results of this study showed that applying zeolite and seed priming with salicylic acid had additive effects on decreasing the Cd sorption by ornamental sunflower that was inoculated with P.indica fungus under drought stress.