Salt-affected soils severely decrease agricultural productivity by reducing the uptake of water and nutrients by plants, toxic ions accumulation and soil structure degradation. The sustainable synthesis of hybrid nanospheres through green approaches has emerged as an effective strategy to enhance crop productivity and improve tolerance to abiotic stress. However, the defensive functions and fundamental mechanisms of green synthesized calcium-doped carbon nano-spheres in protecting maize against salt stress remain elusive. Thus, calcium-doped carbon nanospheres were innovatively synthesized by doping calcium oxide nanoparticles (CaO NPs) with lignin nanoparticles (LNPs) which were further analyzed using Fourier Transform Infrared Spectroscopy (FT-IR), Energy Dispersive X-Ray Spectroscopy (EDX), Field Emission Scanning Electron Microscopy (FE-SEM) and Transmission Electron Microscopy (TEM). These analyses validated the successful doping of Ca@CNs, elucidating the purity and morphology of the hybrid nanospheres. More importantly, the effect of Ca@CNs on maize plants under NaCl stress, unreported so far, was examined. Results of the current study showed that treating salt-stressed plants with Ca@CNs significantly improved maize growth and biomass accumulation by enhanced absorption of minerals and improved photosynthetic efficiency. Furthermore, Ca@CNs application has also reduced NaCl-induced oxidative damage by enhancing antioxidant defense mechanisms and maintaining cellular integrity, resulting in improved resistance to salt stress. Moreover, Ca@CNs substantially up-regulated the expression of salt-tolerant genes ZmNHX3, CBL, ZmHKT1, and MAPK1, as well as genes involved in lignin biosynthesis such as 4CL2, PAL1, CCR, and COMT, in both shoot and root tissues. Conversely, the expression levels of genes Zm00001d003114, Zm0001d026638, Zm00001d028582 and Zm00001d051069 associated with Ca2 +-responsive SOS3 pathway were all down-regulated under NaCl treatment, while up-regulated in the presence of Ca@CNs along with NaCl. The observed changes in transcript levels of these genes highlight the potential of Ca@CNs in alleviating NaCl toxicity. These results demonstrated that the green synthetic Ca@CNs can significantly alleviate salt stress and promote plant growth in saline environments, which will provide a new strategy for the utilization of nanoparticles in agriculture to maintain sustainable agriculture and improve crop yield.

Storage pests, particularly bruchids, are major biotic constraints causing significant storage losses in pulses. Conventional control methods relying on insecticides and fumigants often lead to food contamination due to toxic pesticide residues and a rapid decline in seed germination. In this investigation, through green nano-technological application, a promising and sustainable alternative for pest management is developed. Silver and copper nanoparticles were synthesized through ocimum leaf extract. The characterization of silver and copper nanoparticles was carried out by UV-spectroscopy, particle size analyzer, scanning electron microscopy, X-ray diffraction, and Fourier-transform infrared. Both the nanoparticles were spherical and crystalline in nature. Greengram seeds were primed with standardized silver and copper nanoparticles at different concentrations (1000, 1500, and 2000 ppm) and compared with castor-treated, deltamethrintreated, and untreated control seeds for seed quality, growth, and yield. After one month of storage, all the pulse beetles released in different treatments exhibited 100 % mortality, whereas in control, the insects multiplied. At the end of nine months, the control seeds had shown 72 % damage and 39.67 % germination. In contrast, silver nanoparticles at 1000 ppm showed no seed damage and achieved 81.67 % germination, which was on par with copper nanoparticles at 1000 ppm with 79.33 % germination. Seed priming of silver and copper nanoparticles at 1000 ppm also demonstrated superior performance in all the seed quality and biochemical parameters (alpha amylase and catalase) throughout the storage period. Whereas, in the greenhouse experiment, enhanced growth (35.96 cm, 46.48 cm, and 53.00 cm at 30, 60 DAS, and at harvest, respectively) and yield per plant (3.75 g) were significantly higher in plants that were given foliar application with silver nanoparticles at 1000 ppm. Furthermore, foliar application of these nanoparticles at all concentrations (1000, 1500, and 2000 ppm) did not exhibit any adverse effects on soil microbial organisms, as assessed by dehydrogenase enzyme activity. Hence, this research highlights the potential use of silver and copper nanoparticles at 1000 ppm as effective tools for storage pest management and contributing to improved agricultural productivity and sustainability.