Blueprinting morpho-anatomical episodes via green silver nanoparticles foliation

Abstract

Traditional fertilization not only enhances the acidification of soil but also leads toward eutrophication. Here stimulatory and inhibitory effects of foliar fertilization of Cordia based silver nanoparticles (AgNPs) were studied on lettuce (Lactuca sativa L.) biomass accumulation, antioxidant activity, and morphological and anatomical modifications. The AgNPs were foliar supplied with a concentration of 25, 50, and 100 ppm along with control (deionized water) and negative control AgNO3 for consecutive 25 days. The L. sativa fresh and dry biomass accumulation were significantly higher by 53%, leaf area by 25%, and leaf water holding capacity by 207% for foliar sprayed at 25 ppm concentration of AgNPs. The application of AgNPs and AgNO3 had significantly shortened the shoot length (52%), while foliar spray of AgNPs promoted the root length (40%). Among different concentrations of AgNPs, the 50 ppm improved the thickness of stem epidermis (44%), hypodermis (130%), and cortex cell area (372%). For antioxidant studies, the 25 ppm of AgNPs depicted the highest anti-oxidative activity for 2,2-diphenyl-1-picryl hydrazyl radical scavenging activity (75%), total antioxidant capacity (167%), total phenolic content (292%), and total reducing power (60%), while 50 ppm showed the maximum activity for total flavonoid content (243%) as compared to control. Thus, we may conclude that the AgNPs have both stimulatory and inhibitory effects on L. sativa. These effects were dependent on the concentration of the nanoparticles and have varied for different growth, antioxidants, and anatomical traits of the plant.