Green nanopriming: responses of alfalfa (Medicago sativa L.) seedlings to alfalfa extracts capped and light-induced silver nanoparticles

Abstract

The application of nanotechnology in agriculture can remarkably improve the cultivation and growth of crop plants. Many studies showed that nanoparticles (NPs) made plants grow more vigorously. Light can make NPs aggregated, leading to the reduction of the NPs toxicity. In addition, treatment with NPs had a “hormesis effect” on plants. In this study, light-induced silver nanoparticles (AgNPs) were synthesized by using the alfalfa (Medicago sativa L.) extracts, and then the optimal synthetic condition was determined. Light-induced AgNPs were aggregated, spherical and pink, and they were coated with esters, phenols, acids, terpenes, amino acids and sugars, which were the compositions of alfalfa extracts. The concentration of free Ag+ was less than 2 % of the AgNPs concentration. Through nanopriming, Ag+ got into the seedlings and caused the impact of AgNPs on alfalfa. Compared with the control group, low concentration of light-induced AgNPs had a positive effect on the photosynthesis. It was also harmless to the leaf cells, and there was no elongation effect on shoots. Although high concentration of AgNPs was especially beneficial to root elongation, it had a slight toxic effect on seedlings due to the accumulation of silver. With the increase of AgNPs concentration, the content of silver in the seedlings increased and the silver enriched in plants was at the mg/kg level. Just as available research reported the toxicity of NPs can be reduced by using suitable synthesis and application methods, the present light induction, active material encapsulation and nanopriming minimized the toxicity of AgNPs to plants, enhancing the antioxidant enzyme system. Graphical Abstract

The Size-Dependent Effects of Silver Nanoparticles on Germination, Early Seedling Development and Polar Metabolite Profile of Wheat (Triticum aestivum L.)

“…However, our study did not show this either ( Figure 5 B, Table S3 ). Similarly, the lack of effect of Ag NPs on α-amylase activity was last recently revealed in germinating alfalfa (Medicago sativa) seeds [ 66 ].…”

UV‐Induced Oxidation Preparation of Multi‐Functional Lignin‐Based AgNPs and its Application for Conductive Coating, Antibacterial Enhancement, and Product Separation

“…The results indicated that THF could oxidize and etch lignin-based AgNPs to release Ag + under UV irradiation, accompanied by the fusion and growth of AgNPs induced by photo-reduction until precipitation occurs. [5,33,34] In addition, the literature showed that AgNPs itself would slowly dissolve and release Ag + . [24,35] Under dark conditions, we found that the absorption peak intensity decreased by 21 % after 12 h. Although dissolved, it is much lower than that under UV irradiation.…”

In Vivo Biosynthesis of Au and Ag NPs Using Two Medicago sativa L. Genotypes

“…Plants are commonly used for NP biosynthesis due to the possibility of growing them easily or maintaining them more easily than bacteria and animals. Various agricultural plants, such as alfalfa (Medicago sativa L.) [17][18][19] and Aloe vera L. [20], are used in NP biosynthesis studies because they contain many biomolecules, such as phenols glucose, fructose, ascorbic acid, and citric acid [20][21][22][23], which can divide metal precursors, for example, AgNO 3 and HauCl 4 to Ag and Au NPs [22][23][24].…”