**2.7 Carbon nanoparticles (C NPs)**

Carbon nanoparticles have distinctive properties, including morphologically small surface area and better chemical reactivity [47]. They help in increasing seed germination and crop production under salt stress [48]. Application of C NPs on *Brassica* 

*napus* increased the NaCl stress tolerance in the plant by reestablishing ion homeostasis and redox balance [49]. When *Ocimum basilicum* was treated with C NPs increased enzymatic and nonenzymatic defense systems, and increased carotenoid and chlorophyll content [50]. Proline content in roots and leaves, photosystem II activity, soluble sugar in leaves were increased, and membrane integrity was maintained due to an increase in unsaturated fatty acid in *Sophora alopecuroides* C NPs treated plants under salt stress [51]. Application of C NPs on *Triticum aetivum* plants under saline conditions enhanced phosphorus and potassium content in roots and phosphorus content in shoot and increased the activity of antioxidant enzymes and improved the chlorophyll content, free ascorbic acid, amino acid, and soluble sugars [52]. **Table 1** consists of the reports of different scientists who studied the effects of the treatment of different nanoparticles on different plant species and their responses to physiological levels under salt stress.
