Role of magnesium oxide nanoparticles in the mitigation of lead-induced stress in Daucus carota: modulation in polyamines and antioxidant enzymes

During the current study, the effects of magnesium oxide nanoparticles (5 mmol/L) were observed on the growth and mineral nutrients of Daucus carota under lead (Pb) stress. The results demonstrated that Pb stress decreased the growth and photosynthetic rate of D. carota plants. Furthermore, Pb stressed plants showed decreased uptake of mineral nutrients including Zn, Na, Fe, K, Ca, Mg, K, and Cu. Similarly, Pb stressed plants showed enhanced electrolyte leakage (EL) and malondialdehyde (MDA) content. However, magnesium oxide nanoparticles detoxified ROS to mitigate Pb stress and improved the growth of plants. Magnesium oxide nanoparticles also escalated the activity of antioxidant enzymes including superoxide dismutase (SOD) and Catalase (CAT). A higher amount of Pb content was observed in the roots as compared to the shoot of plants. Lead toxicity reduced manganese accumulation in D. carota plants. The increased concentration of iron, manganese, copper, and zinc advocates stress the ameliorative role of Pb stress in plants. Novelty statement The role of MgONPs in the alleviation of Pb-toxicity in Daucus carota has never been exploited. In addition, the potential of MgONPs to enhance nutritional content in D. carota via modulation in antioxidant system and polyamines have never been reported.

Automated summary

The study investigated the effects of magnesium oxide nanoparticles on the growth and mineral nutrients of Daucus carota under lead stress. Results showed that the nanoparticles can mitigate the negative impact of lead stress on plants, enhance antioxidant enzyme activity, and improve growth conditions.