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Salinity is a critical issue impairing the growth and productivity of most crop species through the mediated ionic and osmotic imbalances. As a way forward, the current study was tailored to elucidate the capacity of sulfur nanoparticles (SNPs) to amend salinity consequences on growth and physio-biochemical attributes of wheat. In a controlled experiment, wheat seeds were primed for 12 h with either 100 μM SNPs or deionized water then sown in plastic pots containing 5 kg clay-sand mixture (2:1 w/w). A week later, pots received NaCl (100 or 200 mM) as a sole treatment or in combination with SNPs and after three weeks the data of morph-bio-physiological traits were recorded. Salinity decreased growth rate, pigmentation, protein, amino acids, cysteine, ascorbate, flavonoids and phenolics content in wheat leaves. Plants pre-treated with 100 μM SNPs showed improved growth rate, pigmentation, nitrogen metabolism as well as non-enzymatic antioxidant contents as compared with salinized treatments. Neither salt nor SNP treatments affected photosynthetic performance rate (Fv/fm), however both treatments induced glutathione content. SNP treatment retrieved the undue excessive activities of catalase (CAT), peroxidase (POD), ascorbate peroxidase (APX), superoxide dismutase (SOD) and polyphenol oxidase (PPO) besides the increased level of proline caused by salt stress. Likewise, 100 μM SNPs rebalanced the declined nitrogen, phosphorus and potassium contents and decreased sodium uptake caused by salinity. On the whole, priming with 100 μM SNPs improved photosynthetic pigments, nitrogen metabolism, antioxidant status and ionic relations contributing to the enhancement of growth attributes in wheat under salinity.

Increased urbanization detrimentally affects crop plants. Heavy metals pollution sharply threatens food security. However, greenly synthesized nanoparticles were recently proposed as growth bioregulators. To investigate the evolved mechanisms by which sulfur nanoparticles (SNPs) could improve cellular defense against manganese toxicity, the present experiment was applied on Helianthus annuus (L.) seedlings. The experimental design was based on priming of sunflower seeds for 18 h in different (12.5–200 μM) SNPs, while 100 mM manganese sulfate (MnSO4) was implemented as irrigation treatment. The 14-day-old seedlings manifested Mn noxiousness and oxidative stress indications such as increased reactive oxygen species (O2·− and H2O2) and lipid peroxidation. Manganese exposure severely lowered the activity of some antioxidant enzymes like superoxide dismutase (SOD) and catalase (CAT), while induced ascorbate peroxidase (APX), guaiacol peroxidase (POX), polyphenol oxidase (PPO), and glutathione reductase (GR) activities. An evident decline in the pool of antioxidant compounds, such as ascorbic acid (ASA), glutathione (GSH), and total flavonoids content (TFC), was attained with Mn stress. Priming with SNPs significantly stimulated CAT and SOD activities and enhanced the antioxidant compounds (ASA, TFC, and total phenolic compounds) level in Mn-stressed seedlings. Consequently, SNPs caused a significant decrease in O2·−, H2O2, and lipid peroxidation and their oxidative damage. However, a significant reduction in GSH was detected with SNPs that might be consumed and incorporated into biosynthesis of other chelating ligands. Therefore, SNPs manifested a vital role in Mn detoxification through counterbalancing oxidative damage and elevating the antioxidant defense machinery.

A novel green approach was utilized to fabricate sulfur nanoparticles (SNPs) with the aid of Ocimum basilicum leaves extract. The effective formation of the synthesized SNPs was examined and approved using UV–visible spectroscopy, X-ray diffraction (XRD), transmission electron microscopy (TEM), and Fourier transform infrared (FT-IR) spectroscopy. The average particle size was 23 nm with spherical shape and crystalline in nature. In the pot experiment, the synthesized SNPs were applied with different concentrations (12.5, 25, 50, 100 and 200 μM) as pre-soaking to Helianthus annuus seeds and irrigated with 100 mM MnSO4. As a result of manganese (Mn) exposure, the harvested 14-day sunflower seedlings showed a significant decline in the growth parameters (shoot length, leaf area and the relative water content of both shoot and root), photosynthetic pigments, mineral content (N, P, K, Ca, and Mg), and protein content compared to the control. The root length, electrolyte leakage, Na and Mn levels, metabolites content (amino acids, protein, glycine betaine, proline, and cysteine) were greatly raised as affected by Mn stress. Mn toxicity reduction using SNPs was demonstrated, as the medium doses enhanced seedlings growth, photosynthetic pigments, and mineral nutrients. Application of SNPs decreased Mn uptake and enhanced S metabolism through increasing cysteine level. Likewise, SNPs elevated seedlings water content and eliminated physiological drought via increasing osmolytes such as amino acids and proline. It can be concluded that green-synthesized SNPs had the potential to limit the deleterious effects of Mn stress.

T HE EFFECT of CuSO4 stress on some growth parameters and some metabolites in 14-day-old Vicia faba seedlings was studied. Irrigation with 150 mM CuSO4 resulted in remarkable reduction in root length, shoot height, fresh and dry weights of root and shoot, leaf area and photosynthetic pigments (Chl a, Chl b and carotenoids), while it raised Chl a/b ratio. Total soluble carbohydrates and protein contents were significantly depleted under Cu treatment. The ameliorative role of seed priming with different concentrations of yeast extract (25, 50, or 100 %), IAA (0.1, 0.3, 0.5 mM), or the green-synthesized Nano zinc oxide with average size 61 (nm) prepared from leaf extract of Coriandrum sativum (10, 50, 100 ppm) for different periods (6 and10h for yeast and IAA, 3 and 6h for Nano ZnO were studied. Results revealed that seed priming with 50% yeast or 0.1 mM IAA for 10h showed a remarkable increase in the measured growth criteria, chla, chl b, soluble carbohydrates and proteins but diminished chl a/b ratio compared with the Cu stress treatment. Seed priming with 100 ppm Nano ZnO for 6 h exhibited the most effective treatment in mitigating the harmful effects of Cu stress on growth criteria, Chla, Chl b, soluble carbohydrates and proteins.