Application of salicylic acid and zeolite for reducing alkalinity stress in black seed (Nigella sativa L.)

The use of modifiers can reduce the effects of environmental stress in plants. The aim of this study was to investigate the effect of salicylic acid and zeolite in reducing alkalinity stress in black seed (Nigella sativa L.). A factorial experiment was conducted based on a completely randomized design with three replications in 2022 in the greenhouse of Razi university, Kermanshah. The factors included alkalinity stress (at three levels of 0, 50 and 100 mM as NaHCO3), salicylic acid (at three levels of 0, 0.5 and 1 mM), and zeolite (at three levels of 0, 0.25 and 0.5 % by weight). The results showed that the effects of salicylic acid and zeolite on most of the plant growth characteristics under alkalinity stress were significant (P ≤ 0.01). The highest amount of proline (12.65 μmol/g) and soluble sugars (0.2 mg/g) were obtained under severe alkalinity stress without the use of salicylic acid and zeolite. Also, the highest shoot height (24.6 cm), root length (19.5 cm), shoot dry mass (0.78 g) and leaf area (22.47 cm2) were obtained without alkalinity and with application of 1 mM salicylic acid and 0.5 % zeolite. In general, the use of salicylic acid, as a plant hormone, and zeolite, as a soil amendment, is a suitable and cheap strategy to reduce the effects of alkalinity stress in black seed.