Nano-fertilizers are a new tool that can be used to address plant production challenges, and it addresses such nutrient deficiencies through smart agriculture approaches. Iron (Fe) is a vital element for several metabolic and physiological processes; however, Fe deficiency is common in poorly fertile soils (sand soil) and in arid areas. Therefore, additional research is required to select the most efficient form of iron absorbance. This research was implemented on broad bean plants (Vicia faba L. var. major Harz) to examine the impact of three iron sources: nano-iron (FeNPs, T1), iron sulfate (T2), and chelated iron (T3) as a foliar spray on the morphological properties, physiological attributes, and nutritional status of these plants compared to the untreated plants (control). The obtained results showed that foliar spraying with FeNPs, chelated iron and sulphate iron fertilizers increased plant height by 35.01%, 26.2, and 20.4%; leaf area by 38.8%, 18.3%, and 8.1%; the fresh weight of the plant by 47%, 32.8%, and 7.3%; the dry weight of the plant by 52.9%, 37.3%, and 11.2%; and the number of branches by 47%, 31.3%, and 25.6 %, respectively, compared to the control treatment (CT). Furthermore, the application of FeNPs, chelated iron, and sulphate iron fertilizers improved the number of pods by 47.9%, 24.8%, and 6.1%; the number of seeds by 32.8%, 7.9%, and 2.8%; and seed weight by 20.8%, 9.1%, and 5.4%, compared to control treatment (CT). Additionally, foliar application of FeNPs showed the highest values of photosynthesis rate (Pn), water-use efficiency (WUE), total chlorophyll, and phytohormones (IAA, GA3) compared to all the other treatments. The anatomical structure revealed an enhancement of leaf size and thickness (epidermis cells and mesophyll tissue) affected by FeNPs treatment compared to other treatments. Foliar application of FeNPs also improved the total content of carbohydrates, crude protein, element content (N, P, K, Ca, Na, Fe, Zn, Mn, and Cu), and some amino acids such as lysine, arginine, phenylalanine, isoleucine, and tyrosine in the seeds of broad beans. Based on the above results, the maximum values of all tested measurements were observed when FeNPs were used as the foliar spraying followed by chelated and sulphate iron fertilizers. Therefore, these findings suggest that using FeNPs, as a foliar treatment, could be a promising strategy for reducing the Fe deficiency in sandy soil and enhancing plant growth, pod yield, and pod quality of broad bean plants in addition to being environmentally favored in arid areas.

Drought can affect all growth stages and has a significant effect on seed germination, which affects all physiological and metabolic germination processes. It also leads to dehydration, which increases the oxidation of lipids and membranes and disrupts the functioning of biomolecules in plants. Zinc is an essential element for several enzymes involved in metabolism, cell elongation, preservation of the strength and integrity of cell membranes, seed development, and resistance to environmental stress. A pot experiment was conducted to determine how ZnO seed priming, either in the form of ZnO NPs (nanopriming) or ZnO bulk priming (60 mg L^− 1), counteracts the negative impacts of drought at different levels (80% and 60% FC) on wheat (Triticum aestivum L.) seedlings at the seedling stage. A recent experiment revealed that seed priming agents significantly mitigate the negative effects of drought stress, especially at 60% FC, by positively influencing various parameters of wheat seedlings. Notably, the POD activity increased by 91.8% and 289.9% for the shoots, 218.6% and 261.6% for the roots, the phenolic content increased by 194.4% for the shoots and 1139.6% for the roots, the H₂O₂ scavenging percentage increased by 124.9% and 135.4% for the shoots and 147.6% for the roots, and the lipid peroxidation inhibition percentage increased by 320.6% and 433% for the shoots. Moreover, the utilization of seed priming agents had a profound effect on free amino acids (393.8%, 502.8% for roots) and soluble carbohydrates (183.4% for roots) compared with those in stressed seedlings without priming. Experimental and computational methods (time-dependent density functional theory (TD-DFT)) were employed to perform IR and XRD analyses of the isolated molecules of the ZnO NPs/Iso. In conclusion, the application of ZnO NPs or bulk ZnO was found to create effective mechanical and physiological barriers, as confirmed by the analysis of antioxidant enzyme activities, nonenzymatic components, free radical scavenging, and osmoprotectant constituents.

Despite the considerable efforts reported so far to enhance seed priming, novel ideas are still needed to be suggested to this sustainable sector of agri-seed industry. This could be the first study addressing the effect of nitric oxide (NO) under open field conditions. The impacts of seed redox-priming using sodium nitroprusside (SNP) and osmo-priming with calcium chloride (CaCl₂), both applied individually or successively, were investigated under salinity stress conditions on wheat plants (Triticum aestivum L.). Various parameters, including water relations, growth, yield, photosynthetic pigments, and antioxidant activities (enzymatic and non-enzymatic), were recorded to assess the outcomes of these priming agents on mitigating the negative impacts of salinity stress on wheat plants. Water consumptive use (ETa) and irrigation water applied (IWA) decreased with seeds priming. Successive priming with SNP + CaCl₂ induced the greatest values of crop water productivity (CWP), irrigation water productivity (IWP), seed index, grain yield and grain nitrogen content.Under salinity stress, the dry weight of plants was decreased. However, hydro-priming and successive chemical priming agents using combinations of calcium chloride and sodium nitroprusside (CaCl₂ + SNP & SNP + CaCl₂) preserved growth under salinity stress.Individual priming with sodium nitroprusside (SNP) and calcium chloride (CaCl₂) resulted in the lowest recorded content of sodium in the shoot, with a value of 2 ppm. On the other hand, successive priming using CaCl₂ + SNP or SNP + CaCl₂ induced the contents of potassium in the shoot, with values of 40 ppm and 39 ppm, respectively. Malondialdehyde decreased in shoot significantly withapplicationof priming agents. Successive priming with CaCl₂ + SNP induced the highest proline contents in shoot (6 µg/ g FW). The highest value of phenolics and total antioxidants contents in shoot were recorded under successive priming using CaCl₂ + SNP and SNP + CaCl₂.Priming agents improved the activities of ascorbate peroxidase and catalase enzymes. The successive priming improved water relations (ETa, IWA, CWP and IWP) and wheat growth and productivity under salinity stress more than individual priming treatments.

Recently, seed priming has gained significant attention as a technique to enhance stress tolerance in various crop plants. The current research investigated the alleviative effect of seed priming with silicon (Si, 2 mM Na2SiO3) on the early growth and antioxidant activity of fenugreek (Trigonella foenum-graecum L.), an aromatic and medicinal plant when exposed to zinc oxide nanoparticles (ZnO NPs) toxicity levels (0, 100, and 200 mg L-1). The findings revealed that ZnO NPs toxicity had a notable detrimental effect on growth-related factors. However, Si priming proved effective in attenuating oxidative stress, promoting growth, and increasing the levels of soluble metabolites (soluble carbohydrates, soluble proteins, and free amino acids) in the presence of ZnO NPs toxicity. Moreover, Si priming significantly enhanced both enzymatic and non-enzymatic plant antioxidants compared to non-primed plants under ZnO NPs stress. Therefore, the results of this study support the use of seed priming in Si which was mostly effective in improving the growth and physiological traits of fenugreek plants by alleviating the detrimental effects of ZnO NPs toxicity.

The global food security is threatened by the accumulation of anthropogenic nanomaterials in the environment. We investigated the phytotoxic effects of elevated zinc oxide nanoparticles ([ZnO]NPs: 300–400 mg L⁻ ¹ ) on wheat ( Triticum aestivum L.) and evaluated a novel detoxification strategy using successive redox-priming. Wheat caryopses were primed with alpha-lipoic acid (LA) and sodium nitroprusside (SNP, a nitric oxide donor) either individually or in successive sequences (LA→SNP and SNP→LA). Exposure to [ZnO]NPs resulted in significant growth inhibition, reduction of biomass and degradation of chlorophyll. However, successive priming, particularly the LA+SNP combination, significantly attenuated these negative effects. This treatment effectively restored seedling growth by creating a strong antioxidant shield, greatly increasing the activities of SOD, POD, CAT, and APX, and raising metal chelating activity to 98.1%. Furthermore, Density Functional Theory (DFT) calculations, including HOMO–LUMO and molecular electrostatic potential (MEP) analyses, gave mechanistic insights into the molecular interactions of the priming agents and ZnO, highlighting their role as potent radical scavengers and stabilizers. The results indicate that a successive redox priming is an effective and sustainable approach to enhance crop tolerance to high concentrations of nanoparticle toxicity.