Salinity is one of the most prevalent abiotic stresses which not only limits plant growth and yield, but also limits the quality of food products. This study was conducted on the surface functionalization of phosphorus-rich mineral apatite nanoparticles (ANPs), with thiourea as a source of nitrogen (TU–ANPs) and through a co-precipitation technique for inducing osmotic stress tolerance in Zea mays. The resulting thiourea-capped apatite nanostructure (TU–ANP) was characterized using complementary analytical techniques, such as EDX, SEM, XRD and IR spectroscopy. The pre-sowing of soaked seeds of Zea mays in 1.00 µg/mL, 5.00 µg/mL and 10 µg/mL of TU–ANPs yielded growth under 0 mM, 60 mM and 100 mM osmotic stress of NaCl. The results show that Ca and P salt acted as precursors for the synthesis of ANPs at an alkaline pH of 10–11. Thiourea as a source of nitrogen stabilized the ANPs’ suspension medium, leading to the synthesis of TU–ANPs. XRD diffraction analysis validated the crystalline nature of TU–ANPs with lattice dimensions of 29 nm, calculated from FWHM using the Sherrer equation. SEM revealed spherical morphology with polydispersion in size distribution. EDS confirmed the presence of Ca and P at a characteristic KeV, whereas IR spectroscopy showed certain stretches of binding functional groups associated with TU–ANPs. Seed priming with TU–ANPs standardized germination indices (T50, MGT, GI and GP) which were significantly declined by NaCl-based osmotic stress. Maximum values for biochemical parameters, such as sugar (39.8 mg/g at 10 µg/mL), protein (139.8 mg/g at 10 µg/mL) and proline (74.1 mg/g at 10 µg/mL) were recorded at different applied doses of TU–ANP. Antioxidant biosystems in the form of EC 1.11.1.6 catalase (11.34 IU/g FW at 10 µg/mL), EC 1.11.1.11 APX (0.95 IU/G FW at 10 µg/mL), EC 1.15.1.1 SOD (1.42 IU/g FW at 5 µg/mL), EC 1.11.1.7 POD (0.43 IU/g FW at 5 µg/mL) were significantly restored under osmotic stress. Moreover, photosynthetic pigments, such as chlorophyll A (2.33 mg/g at 5 µg/mL), chlorophyll B (1.99 mg/g at 5 µg/mL) and carotenoids (2.52 mg/g at 10 µg/mL), were significantly amplified under osmotic stress via the application of TU–ANPs. Hence, the application of TU–ANPs restores the growth performance of plants subjected to induced osmotic stress.

Plants are sessile and mostly exposed to various environmental stresses which hamper plant growth, development, and significantly decline its production. Drought stress is considered to be one of the most significant limiting factors for crop plants, notably in arid and semi-arid parts the world. Therefore, the present study aimed to evaluate the potential impact of different concentrations (10, 100, and 200 µg/mL) of kinetin capped zinc oxide nanoparticles (Kn-ZnONPs) on Vigna radiata (L.) R. Wilczek under varying levels (5%, 10%, 15%) of PEG-induced drought stress. ZnONPs were synthesized by a co-precipitation method using Zinc acetate as a precursor at pH-12, incinerated to 500 °C, and kinetin was used as a surface functionalizing agent. The resulting Kn-ZnONPs were characterized by various contemporary analytical techniques, including SEM, SEM-EDS, XRD, DLS, and Zeta potential and IR spectroscopy. Crystalline Kn-ZnONPs, with a zeta potential of 27.8 mV and a size of 67.78 nm, of hexagonal wurtzite structure and vibrational stretches associated with N-H, C-O, C-N, etc., were confirmed. PEG-induced drought stress significantly reduced the growth of V. radiata by declining the chlorophyll and carotenoid contents. Moreover, a significant decrease in the levels of superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), ascorbate peroxidase (APX), soluble sugar contents, proline, protein contents, phenol, and tannin were observed compared to the control. However, the exogenous application of Kn-ZnONPs ameliorated all photosynthetic parameters by up-regulating the antioxidant defense system through the promotion of SOD, POD, CAT, and lipid peroxidation levels. The biochemical parameters, such as proteins, soluble sugars, and proline, were observed to be maximum in plants treated with 200 µg/mL Kn-ZnONPs under 5% drought stress. The application of Kn-ZnONPs also enhanced the total phenol contents, flavonoid, and tannin contents. In conclusion, the findings of this study demonstrate that the exogenous application of Kn-ZnONPs provides beneficial effects to V. radiata by attenuating the damaging effects of drought stress through the up-regulation of the antioxidant defense system and osmolytes. These results suggest that Kn-ZnONPs have potential as a novel approach to improve crop productivity under drought stress conditions.

Rising soil salinity is a major concern for agricultural production worldwide, particularly in arid and semi-arid regions. To improve salt tolerance and the productivity of economic crop plants in the face of future climatic changes, plant-based solutions are required to feed the continuously increasing world population. In the present study, we aimed to ascertain the impact of Glutamic-acid-functionalized iron nanoparticles (Glu-FeNPs) on two varieties (NM-92 and AZRI-2006) of mung beans with different concentrations (0, 40 mM, 60 mM, and 80 mM) of osmotic stress. The result of the study showed that vegetative growth parameters such as root and shoot length, fresh and dry biomass, moisture contents, leaf area, and the number of pods per plant were significantly decreased with osmotic stress. Similarly, biochemicals such as protein, chlorophylls, and carotenes contents also significantly declined under induced osmotic stress. The application of Glu-FeNPs significantly (p ≤ 0.05) restored both the vegetative growth parameters and biochemical contents of plants under osmotic stress. The pre-sowing treatment of seeds with Glu-FeNPs significantly ameliorated the tolerance level of Vigna radiata to osmotic stress by optimizing the level of antioxidant enzymes and osmolytes such as superoxide dismutase (SOD), peroxidase (POD), and proline contents. Our finding indicates that Glu-FeNPs significantly restore the growth of plants under osmotic stress via enhancing photosynthetic activity and triggering the antioxidation system of both varieties.

Heavy metal stress, including lead, adversely affects the growth and yield of several economically important crops, leading to food challenges and significant economic losses. Ameliorating plant responses to various environmental stresses is one of the promising areas of research for sustainable agriculture. In this study, we evaluated the effect of aspartic acid-functionalized copper nanoparticles on the photosynthetic efficiency and antioxidation system of maize plants under Pb toxicity. The ion reduction method was employed for the synthesis of CuNPs, using ascorbic acid as the reducing agent and aspartic acid as the surface functionalizing agent. Isolated experiments under laboratory and field conditions were performed using a randomized complete block design (RCBD). Seeds primed in water, 1.0, 5.0, and 10 µg/mL of Asp-CuNPs were sown under 0, 500, and 1000 mg/L Pb stress in laboratory conditions, while primed seeds along with foliar-applied Asp-CuNP plants were grown in a field under applied Pb stress, and the obtained data were statistically analyzed using TWANOVA. The laboratory experiment shows that Asp-CuNPs act both as a plant growth regulator (PGR) and plant growth inhibitor (PGI), depending upon their concentration, whereby Asp-CuNPs act as a PGR at a concentration of 1 µg/mL ≤ X ≤10 µg/mL. The field experiment confirms that seed priming and foliar spraying with Asp-CuNPs activate embryos and enhance plant growth in a dose-dependent manner. In addition, Asp-CuNPs (10 µg/mL) significantly increase chlorophyll content to 0.87 mg/g from 0.53 mg/g (untreated) when plants were exposed to Pb toxicity at 1000 mg/kg of soil. It is noteworthy that Asp-CuNPs induce resilience to Pb toxicity (1000 mg/kg of soil) in plants by reducing its root absorption from 3.68 mg/kg (0 µg/mL Asp-CuNPs) to 1.72 mg/kg with the application of 10 µg/mL Asp-CuNPs. Additionally, histochemical analyses with NBT and hydrogen peroxide revealed that ROS accretion in plants treated with Asp-CuNPs declined because of the augmentation of antioxidant enzyme (POD, SOD, APOX, etc.) activities under Pb toxicity. Our findings suggest that amino acid-functionalized copper nanoparticles regulate plant defensive mechanisms related to lead tolerance, which is a promising approach for the induction of resistivity to heavy metal stress.

Climate variability has been a catalytic factor in inducing both biotic and abiotic stresses, exerting detrimental impacts on crop yields. This, in turn, leads to the manifestation of biochemical and physiological impairments within plant systems. This study aimed to evaluate the effects of different concentrations of resorcinol and biochar on tomato (Lycopersicon esculentum Mill.) growth, primary and secondary metabolites, and antioxidant enzyme content levels. Biochar was synthesized from Cedrus deodara (Roxb. ex D. Don) G. Don, sawmill shavings using pyrolysis and subjected to comprehensive characterization employing contemporary techniques including scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD) analysis, Fourier transform infrared (FTIR) spectroscopy, and UV-vis spectroscopy (UV). Both resorcinol at 0.1 μM/L and biochar at 30 mg/L significantly enhanced tomato seed germination and plant growth, promoting increased shoot/root length and fresh/dry weights in tomato plants compared to controls. This supplementation also amplifies tomato chlorophyll contents, growth metabolites, and antioxidant enzyme activities, contributing to robust plant development. Resorcinol at 0.1 μM/L concentration significantly enhanced total protein (79.9 μg/g), total phenol (58.8 μg/g), total proline (0.03 μg/g), total lipid (3.8 μg/g), total soluble sugar (42.5 μg/g), and flavonoid (0.09 μg/g) as compared to control. Biochar at 30 mg/L concentration showed maximum values of total protein (92.1 μg/g), total phenol (61.3 μg/g), total proline (0.03 μg/g), total lipid (5.5 μg/g), total soluble sugar (48.9 μg/g), and flavonoid (0.08 μg/g). This research indicated that foliar application of these specific concentrations of resorcinol and biochar has the ability to improve tomato plant growth, osmolytes, and antioxidant activity.

Nanotechnology is one of the most advance and multidisciplinary fields. Recent advances in nanoscience and nanotechnology radically changed the way we diagnose, treat, and prevent various diseases in all aspects of human life. The use of plants and their extracts is one of the most valuable methods towards rapid and single-step protocol preparation for various nanoparticles, keeping intact “the green principles” over the conventional ones and proving their dominance for medicinal importance. A facile and eco-friendly technique for synthesizing silver nanoparticles has been developed by using the latex of Euphorbia royleana as a bio-reductant for reducing Ag+ ions in an aqueous solution. Various characterization techniques were employed to validate the morphology, structure, and size of nanoparticles via UV–Vis spectroscopy, XRD, SEM, and EDS. FTIR spectroscopy validates different functional groups associated with biomolecules stabilizing/capping the silver nanoparticles, while SEM and XRD revealed spherical nanocrystals with FCC geometry. The results revealed that latex extract-mediated silver nanoparticles (LER-AgNPs) exhibited promising antibacterial activity against both gram-positive and -negative bacterial strains (Bacillus pumilus, Staphylococcus aureus, E. coli, Pseudomonas aeruginosa, and Streptococcus viridians). Both latex of E. royleana and LER-AgNPs were found to be potent in scavenging DPPH free radicals with respective EC50s and EC70s as 0.267% and 0.518% and 0.287% and 0.686%. ROSs produced in the body damage tissue and cause inflammation in oxidative stress-originated diseases. H₂O₂ and OH* scavenging activity increased with increasing concentrations (20–100 μg/mL) of LER-AgNPs. Significant reestablishment of ALT, AST, ALP, and bilirubin serum levels was observed in mice intoxicated with acetaminophen (PCM), revealing promising hepatoprotective efficacy of LER-AgNPs in a dose-dependent manner.