Nano-silicon application enhances salt stress tolerance in <i>Lens culinaris</i> L.: a comparative study with bulk silicon

Salinity stress inhibits the growth and yields of crops by influencing the photosynthetic process, inhibiting root growth, reducing water uptake, and interfering with nutrient uptake and chlorophyll production. Lentil is one of the most nutritious legumes, which is reported to be sensitive to salt stress. Silicon (Si) is a nourishing component for many crops and can be used to moderate abiotic stress in plants. Furthermore, Si in nano-form can further enhance the favorable characteristics of Si to combat the negative impacts of stress. However, little is known about the possibility and mechanisms of using nano-silicon (nSi) in alleviating the effects of salt stress on lentils. Therefore, a pot experiment was conducted to investigate the effects of three levels of Si (control, 100 mg kg⁻¹, and 200 mg kg⁻¹) and nSi at 125 mg kg⁻¹ on lentil (variety Punjab Masoor-2020) growth under varying saline conditions (control i.e. 2.5 dS m⁻¹, 6 dS m⁻¹ and 9 dS m⁻¹). The outcome exhibited the detrimental effects of salinity on the growth and yield of lentils resulting in reduced plant shoot and root growth, yield, soil plant analyzer development (SPAD) value of total chlorophyll contents (TCC), and membrane stability index (MSI), relative water content (RWC), potassium (K⁺), and enhanced sodium (Na⁺) concentration. Whereas, applying Si lessened the effects of salinity and improved lentil yields in normal as well as saline conditions. The application of Si significantly (p ≤ 0.05) enhanced plant growth, yield, SPAD value, MSI, RWC, K⁺ concentration, and reduced Na⁺ concentration. Among the applied Si treatments, SiNP at 125 mg kg⁻¹ most effectively mitigated the salinity stress by augmenting salinity tolerance in lentil plants.