Chromium (Cr) has currently been classified as a hazardous heavy metal due to its toxic effects on both human health and plants growth. This study investigates the restorative effect of phosphorus (P) on Solanum lycopersicum under chromium-induced toxicity. Plant growth was reduced by the addition of 25 mg/L Cr treatment when compared with control, while it was improved by the addition of 13% of P to growth media when compared to the Cr treatment. The shoot and root of the plant growth was increased by 4.0 and 14.0% when treated with 25 mg/L Cr + P treatment. Cr and P combination improved photosynthetic pigments, while it was decreased in Cr treatment alone. Cr dose was increased, and then malondialdehyde (MDA) and hydrogen peroxide (H2O2) also get increased. Lower dose of Cr increases the activities of antioxidative enzymes like superoxide dismutase (SOD), catalase (CAT) and peroxidase (POX), but showed a slight reduction at higher Cr concentrations. The alleviating effect of P was confirmed by the reduction of (H2O2), MDA concentrations and antioxidant enzyme activity in shoot and root tissue. The maximum SOD activity in S. lycopersicum tissues was found to be 330.5% in 25 mg/L Cr treatment, but SOD activity was reduced by 1.76 and 55.73% in tissues treated with Cr with P addition treatment compared to Cr alone treatment. At 25 mg/L Cr treatment CAT activity was increased to 224.8% and 342.3%. These results indicated that replacing P with Cr could reduce Cr-induced toxicity, which could promote seedling growth. This study can be considered as a new technology to mitigate the heavy metals induced stress toxicity in plants.
