▎ 摘　　要

NOVELTY - Use of graphene nanoparticle modified by mixing graphene and concentrated nitric acid, heating at 130-150°C and oxidizing for 3-5 hours, for promoting the growth of alfalfa in a salt stress environment, is claimed, where the graphene nanoparticles are mixed with substrate soil used for cultivating alfalfa. USE - Graphene nanoparticle for promoting growth of alfalfa in a salt stress environment, preferably for improving growth parameter of alfalfa, photosynthesis of alfalfa, air hole adjusting ability of alfalfa, anti-oxidation ability of alfalfa, adjusting absorption of inorganic ion by alfalfa, and reducing the damage of the alfalfa root cell in the salt stress environment, where the growth parameter of alfalfa includes plant height, leaf length, leaf width, leaf area, multiple leaf number, root diameter, fresh weight and dry weight (all claimed). ADVANTAGE - The modified graphene nanoparticles do not enter the plant body but improve the properties and adsorption of the soil so that jointly affect and enhance the salt tolerance of alfalfa from the aspects of morphological characteristics, physiological and biochemical aspects and cell level, and provides a reference for the application of graphene materials in improving soil environment and agricultural production.