Document Type : Original Article
Zinc is a necessary micronutrient in plants whose deficiency can alter essential functions in plant metabolism. High concentrations of Zn can be potentially toxic to plants causing phytotoxicity by the formation of reactive oxygen species. On the other hand, sodium nitroprusside (SNP), a donor of nitric oxide (NO) can protect cells from oxidative damage produce by reactive oxygen species. In this study, we examined the effect of different concentrations of Zn (0, 50, 100, 300, and 500 μM) on growth and physiological parameters of Plantago major L. under various concentrations of Sodium nitroprusside (0, 50, 100, and 200 μM). The results showed that Zn treatment decreased fresh and dry weight and increased the contents of malondealdehyde, antioxidant, and osmolyte. The starch content on the other hand decreased. Moreover, application of different concentrations of sodium nitroprusside (especially 100 μM) as a donor of nitric oxide, had a favorable effect as it improved the heavy metal stress through increasing the plant’s tolerance against zinc toxicity. However, high concentration of Sodium nitroprusside had a deterrence effect on morphology and physiology of Plantago. major L.