Investigating the effect of sodium nitroprusside in reducing cadmium toxicity in basil (Ocimum basilicum L.) plant

Introduction Basil (Ocimum basilicum L.) is a plant that is cultivated for the first time due to the aroma, extra taste and healing properties. In the medical industry, it is used to treat nerve headaches, calming nerves, fever, diarrhea, and anti-nausea and vomiting. One of the serious environmental problems is soil contamination with heavy metals and has negative effects on human health and agricultural lands. Soil pollution to heavy metals is the result of many human activities such as mining, extraction and melting of metals and the using of fertilizers, pesticides and agricultural fungicides, etc. which endangers human health and ecosystems. The major problem with heavy metals is that these inorganic pollutants are not decomposable, in contrast to organic pollutants. Among heavy metals, cadmium is of particular importance due to the high mobility and dynamism in the soil and absorption by the plant. Many of the agricultural soils of the world have been contaminated due to the long-term using of phosphate fertilizers, sewage sludge, etc. with low to moderate concentrations of cadmium. Sodium nitroprusside is one of the compounds recently tested to reduce the effects of stress on plants. Sodium nitroprusside is a nitric oxide-releasing compound whose role in plants has been the subject of many research studies. This compound is red powder and is a plant growth regulator. The purpose of this study was to investigate the effect of sodium nitroprusside foliar application as a reducing agent on heavy metals stress on growth, vegetative, physiological, antioxidant enzymes and essential oil content of basil plant with different amounts of heavy metal cadmium. Materials and methods This research to investigate the role of sodium nitroprusside in reducing cadmium toxicity in basil plant in a factorial form in a completely randomized design in 2017-2018 was conducted. The applied factors in this study were included cadmium at 0 (control), 10, 20 and 30 mg.kg-1 soil and sodium nitroprusside solution at 0 (control), 50 and 100 μM. The measured traits were included plant height, plant dry weight, number of leaves per plant, essential oil percent, malondialdehyde, superoxide dismutase antioxidant activity, proline and cadmium concentration. Results and discussion The obtained results showed that cadmium was decreased plant height, plant dry weight, number of leaves per plant, essential oil percent and superoxide dismutase activity, and was increased Proline cadmium and malondialdehyde concentrates. The most effect of cadmium on 30 mg.kg-1 treatment was obtained. It was also observed that Sodium nitroprusside using was increased plant height, plant dry weight, number of leaves per plant, essential oil percent and superoxide dismutase activity, and was decreased Proline, cadmium and malondialdehyde concentrations, in general, the most positive effect was obtained in 100 μM sodium nitroprusside using. Based on the results, sodium nitroprusside foliar application could improve the vegetative properties and reduce malondialdehyde under heavy metal cadmium stress conditions. According to the the results, it can be founded the positive effects of sodium nitroprusside, especially in the presence of cadmium and reducing the negative effects of stress on the basil drug. Conclusion It can be concluded that sodium nitroprusside moderates much of the harmful effects of heavy metal cadmium stress in basil plant and improves plant growth under stress conditions. Therefore, in the range of this study results, foliar application of this material on a stressed basal plant can be suggested as a factor for decreasing stress intensity and subsequently increasing yield.