Effects of sodium Nitroprussid and Calcium silicate on the physiological and biochemical parameters of wheat (Triticum aestivum L.) under cadmium stress

Cadmium is a heavy metal with high toxicity that causes to oxidative stress in the plants and animals.The heavy metal stress tolerance in the plants with increasing content of reactiveoxygen species (ROS)require to use antioxidative pathways. Hydroponic experiments were performed with thirteen treatments consisting of a control (neither CdSO4 nor ameliorative factor CaSiO3 and SNP), CdSO4 at 25, 50, 75 and l00 µM concentrations without or with 1.5 mM ameliorative factor SNP or CaSiO3. The desired samples of leaves from 60-days-old plant used for determination activities of ascorbate peroxidase, peroxidase and polyphenol oxidas enzymes and content of chlorophyll a, chlorophyllb, totalchlorophyll, carotenoids, MDA, and proline. The obtained results were indicated that Cadmium decreased chlorophyll a, b, total chlorophyll and carotenoids contents significantly and ascorbate peroxidase, peroxidase, and polyphenol oxidase activities which were increased specially by adding CaSiO3. However, polyphenol oxidase activity increased under Cd stress significantly, which increased with adding ameliorative factor,CaSiO3.The MDA and proline content increased under Cd stress significantly, which decreased by adding ameliorative factors especially CaSiO3. It can be concluding that silicate effects that enhanced the Cd tolerance in Triticum aestivum L. is attribute to the silicate ameliorative effects–suppressed CdSO4 uptake and root to shoot CdSO4 transport. In addition, the silicate ameliorative effects are enhanced the antioxidant defenseactivity.