Silicon Can Improve Nutrient Uptake and Performance of Black Cumin Under Drought and Salinity Stresses

The effects of silicon on reducing the damages caused by drought and salinity stresses have been investigated in certain plants. However, little information is available regarding black cumin (Nigella sativa L.) responses. The present pot experiment was conducted to investigate the role of silicon in the nutrient content and biochemical traits of black cumin under conditions of salinity and drought stresses. Osmotic stress was imposed at seven levels of NaCl or polyethylene glycol (PEG) with -0.24, -0.49, and -0.74 MPa and the control treatment. Silicon (control and 1 mM) was applied in the nutrient solution. The results revealed that decreased osmotic potential in both stresses reduced absorption of nitrogen (N), phosphorus (P), potassium (K), copper (Cu), manganese (Mn), iron (Fe), and zinc (Zn) and increased malondialdehyde (MD) and proline in the shoot. There was a significant reduction in the accumulation of these nutrients in the root, except for that of P and N. Silicon also reduced Na concentration in the root and shoot and increased the absorption and distribution of macronutrients and Zn, Fe, Mn, and Cu in salinity stressed plants. We observed an increase in proline and absorption of elements in drought stressed plants employing silicon. In general, silicon could improve plant growth under stress by the osmoregulation and modulation of absorption and distribution of nutrients. However, these beneficial effects were more substantial in salinity stress. We found that silicon participated in decreasing uptake and transfer of toxic ions and improving potassium content.

Automated summary

This study investigated the effects of silicon on the nutrient content and biochemical traits of black cumin under conditions of salinity and drought stresses. The results showed that silicon improved plant growth under stress by regulating osmotic potential and absorption and distribution of nutrients. These beneficial effects were more pronounced in salinity stress.