Putrescine-functionalized carbon quantum dot (put-CQD) nanoparticles effectively prime grapevine (Vitis vinifera cv....

Salinity is an important global problem with destructive impacts on plants leading to different biochemical and metabolic changes in plants through induced oxidative stress that disturbs metabolism, growth, performance and productivity of plants. Given that putrescine (Put) and carbon quantum dots (CQDs), individually, have promising effects in different plant processes, the idea of their combination in a nano-structure "Put-CQD" lead to its synthesis to evaluate the potential exertion of synergistic effects. The current study aimed to investigate the application of newly-synthesized nanoparticles (NPs) consisting of CQDs and Put in grapevine (Vitis vinifera cv. 'Sultana') under salinity stress conditions. For this purpose, Put, CQDs and Put-CQD NPs at 5 and 10 mg L^- 1 concentrations were applied as chemical priming agents in 'Sultana' grapevine 48 h prior salinity stress imposition (0 and 100 mM NaCl).

Salinity significantly decreased (P ≤ 0.05) morphological parameters, photosynthetic pigments, chlorophyll fluorescence parameters and membrane stability index. In addition, salinity enhanced MDA, H₂O₂, proline content and antioxidant enzyme activity. Results revealed that Put-CQD NPs, particularly at 10 mg L^- 1 concentration, alleviated the destructive impacts of salinity stress by improving leaf fresh and dry weights, K⁺ content, photosynthetic pigments, chlorophyll fluorescence and SPAD parameters, proline content, total phenolics and antioxidant enzymatic activities (CAT, APX, GP and SOD), while decreasing Na⁺ content, EL, MDA and H₂O₂ levels.

To conclude, Put-CQD NPs represent an innovative priming treatment that could be effectively applied on grapevine to improve plant performance under salinity stress conditions.