Responses of Salvia nemorosa L. to silver nanoparticle and methyl jasmonate stimuli under salt stress

The present study evaluated the effects of methyl jasmonate (MeJA) and silver nanoparticles (AgNP) on Salvia nemorosa L. under NaCl stress. To this end, total soluble sugar, total phenolic and flavonoid contents, total antioxidant capacity, H2O2 content, photosynthetic pigment, MDA, and proline contents, and enzymatic antioxidant activities were assessed. When the results for photosynthetic pigment contents were evaluated, the highest levels of total carotenoid content, chlorophyll a, and chlorophyll b were obtained with NaCl + AgNP + MeJA treatment. Under NaCl stress, MDA and H2O2 levels increased, but they decreased when AgNP and MeJA were applied. All treatment groups had higher proline contents than the control group; the NaCl + AgNP + MeJA treatment group had the lowest content, while the NaCl treatment group had the highest. The combined elicitor treatment had little effect on total soluble sugar content. The combined elicitor treatment significantly increased total phenolic and flavonoid contents compared to separate applications. The most effective treatment for scavenging DPPH radicals was NaCl + MeJA, whereas the most effective treatment for scavenging CUPRAC and ABTS radicals was NaCl + MeJA + AgNP. Treatment-related variations were observed in enzyme activities; NaCl + MeJA + AgNP treatment caused the greatest increases in SOD, CAT, and APX activities, whereas NaCl + MeJA treatment resulted in the maximum GR activity. Compared to treatment with NaCl alone, the combined application of AgNP and MeJA improved some physiological and biochemical indices and increased plant resistance to salt stress. The synergistic impact of AgNP and MeJA on reducing the effects of salt stress in Salvia nemorosa L. suggests that these two compounds may strengthen plant resilience under adverse environmental conditions.