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چکیده
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Drought stress is one of the most important environmental constraints that negatively affects the growth and yield of crops worldwide. Recently, nanotechnology has been increasingly employed to improve the tolerance of plants exposed to abiotic stresses such as drought. The present study was designed to investigate the moderating effect of cysteine-graphene quantum dots (GQDs-Cys) on alleviating drought stress in apricot cv. ‘Askarabad’. The interaction between GQDs, Cys, and GQDs-Cys NPs at 10 mg l-1 and water stress (100, 50, and 25% of field capacity) was evaluated by measuring some physiological, chlorophyll fluorescence, and biochemical parameters. The treatments GQDs, Cys, and GQDs-Cys nanoparticles generally mitigated the detrimental effects of 50% and 25% water stress, greatly enhancing the relative water relation characteristics of apricot leaves. GQDs, Cys, and especially GQDs-Cys NPs significantly reduced chlorophyll damage under high drought levels. The presence of GQDs-Cys NPs declined the damage caused by drought in apricots, which was shown by lower levels of MDA and EL. Moreover, drought stress and foliar application of GQDs-Cys resulted in a substantial enhancement in GPX, APX, SOD, and PPO enzyme activities, as well as total flavonoids, phenolics content, and total antioxidant activity in comparison to control plants. The use of GQDs-Cys NPs in stressed and non-stressed conditions positively improved the studied traits of the apricot plants by enhancing the antioxidant system. Taken together, the present findings suggest that GQDs-Cys NPs can be used as promising drought stress-reducing agents in apricot seedlings. The present results indicate that amino acids, including cysteine-doped GQDs, could act as effective nanomaterials for enhancing the development of plants, particularly fruit trees and this article will serve as a reference as it is the very first report regarding the ameliorative role of GQDs-Cys in drought stress mitigation.
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