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Heavy metals are one of the most damaging environmental toxins that hamper growth of plants. These noxious chemicals include lead (Pb), arsenic (As), nickel (Ni), cadmium (Cd) and chromium (Cr). Chromium is one of the toxic metal which induces various oxidative processes in plants. The emerging role of nanoparticles as pesticides, fertilizers and growth regulators have attracted the attention of various scientists. Current study was conducted to explore the potential of zinc oxide nanoparticles (ZnONPs) alone and in combination with plant growth promoting rhizobacteria (PGPR) Klebsiella sp. SBP-8 in Cr stress alleviation in Brassica juncea (L.). Chromium stress reduced shoot fresh weight (40%), root fresh weight (28%), shoot dry weight (28%) and root dry weight (34%) in B. juncea seedlings. Chromium stressed B. juncea plants showed enhanced levels of malondialdehyde (MDA), electrolyte leakage (EL), hydrogen peroxide (H 2 O 2 ) and superoxide ion (O 2 • - ). However, co-supplementation of ZnONPs and Klebsiella sp. SBP-8 escalated the activity of antioxidant enzymes i.e., superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX) in B. juncea grown in normal and Cr-toxic soil. It is further proposed that combined treatment of ZnONPs and Klebsiella sp. SBP-8 may be useful for alleviation of other abiotic stresses in plants., Competing Interests: Declaration of competing interest All the authors declare no conflict of interest., (Copyright © 2024 Elsevier Masson SAS. All rights reserved.)

Current research focused on the potential role of zinc oxide nanoparticles (ZnONPs) and potassium (K+ ) in mitigation of arsenic (As) toxicity in Vicia faba L. seedlings. Faba bean seedlings were grown for 30days in potted soil. As stress curtailed root and shoot length, chlorophyll (Chl) content and net photosynthetic rate in V. faba seedlings. However, ZnONPs and K+ curtailed As stress in faba bean seedling through enhanced activity of superoxide dismutase (SOD), ascorbate peroxidase (APX), catalase (CAT) and peroxidase (POD) enzyme. Furthermore, ZnONPs and K+ significantly enhanced cysteine (Cys) content and serine acetyletransferase (SAT) activity in faba bean seedling exposed to As-toxificated soil. Application of ZnONPs and K+ curtailed superoxide ionic content and hydrogen peroxide (H2 O2 ) accumulation in V. faba seedlings exposed to As-polluted soil. Nitric oxide (NO) content also increased in faba bean seedlings treated with ZnONPs and K+ in normal and As-polluted soil. As stress alleviation was credited to reduce As uptake in faba bean seedlings treated with synergistic application of ZnONPs and K+ . It is proposed that K+ interaction with nanoparticles can be exploited at molecular level to understand the mechanisms involved in abiotic stress tolerance.

The ability of microorganisms to generate resistance outcompetes with the generation of new and efficient antibiotics. Therefore, it is critically required to develop novel antibiotic agents and treatments to control bacterial infections. Green synthesized metallic and metal oxide nanoparticles are considered as the potential means to target bacteria as an alternative to antibiotics. Nanoconjugates have also attracted attention because of their increased biological activity as compared to free antibiotics. In the present investigation, silver nanoparticles (AgNPs), zinc oxide nanoparticles (ZnO NPs), copper oxide nanoparticles (CuO NPs), and iron oxide nanoparticles (FeO NPs) have been synthesized by using leaf extract of Ricinus communis. Characterization of nanoparticles was done by using UV-Vis Spectroscopy, Fourier Transform Infrared Spectroscopy, Scanning Electron Microscopy, Energy Dispersive X-Ray Analyzer, X-ray Diffraction Analysis, and Dynamic Light Scattering Particle Size Analyzer. Interestingly, Streptomycin when combined with AgNPs, ZnO NPs, CuO NPs, and FeO NPs showed enhanced antibacterial activity against clinical isolates of S. aureus which suggested synergism between the nanoparticles and antibiotics. The highest enhanced antibacterial potential of Streptomycin was observed in conjugation with ZnO NPs (11 ± 0.5 mm) against S. aureus. Minimum inhibitory concentration of conjugates of AgNPs, ZnO NPs, CuO NPs, and FeO NPs with streptomycin against S. aureus was found to be 3.12, 2.5,10, and 12.5 μg/mL respectively. The considerable point of the present investigation is that S. aureus, which was resistant to streptomycin becomes highly susceptible to the same antibiotic when combined with nanoparticles. This particular observation opens up windows to mitigate the current crisis due to antibiotic resistance to combat antimicrobial infections efficiently., Competing Interests: All authors declare that they have no competing interests.

• Salt stress can reduce growth and physiochemical characteristics of Zea mays. • Application of zinc oxide NPs improved growth, yield and biochemical parameters of the Z. mays crop. • Priming and foliar spray of ZnO-NPs also fortified the crop with enhanced zinc content. • Application of zinc oxide in form of nanoparticles can activate anti-oxidative defensive approach. Use of zinc oxide nanoparticles (ZnO NPs) has the potential to increase the plant growth and development in agricultural sectors. Mode of application of NPs to plants is also of considerable importance. In present study, zinc oxide nanoparticles were prepared by using black seed extract and zinc salt. Characterized zinc oxide nanoparticles were then used to treat Zea mays L. in two types of treatments namely nano-priming and foliar nano-spray of zinc oxide nanoparticles. For each treatment a range of concentration was used i.e., 100, 200, 400, and 1000 mg/L. Experiment was conducted in randomized complete block design. Hydro-priming was used as a control. Whereas foliar spray was given after 30, 45, and 60 days of sowing. Plants were harvested after 90 days and various growth, physiological, biochemical, yield and stress parameters were studied. Results showed that monodispersed nanoparticles of average size of 45.56 nm were synthesized. Priming with ZnO NPs showed better results as compared to foliar spray of ZnO NPs. Highest germination (100%), Leaf length (350 cm), plant height (65 cm), and no. of leaves (10 leaves per plant) were recorded for corn plants with seed priming treatment of 200 mg/L of ZnO NPs. These values were significantly higher than comparative positive control treatment values (salt-treated plants) as well. Whereas biochemical analysis also supported the results of growth parameters i.e., ZnO NPs treated plants (200–1000 mg/L) showed higher values of sugar (0.6 µg), chlorophyll (1800 µg) and carotenoid content (400 µg). Protein and proline content was higher for zinc salt-treated (positive control) plants. Photosynthetic rate, CO 2 sub-stomatal conductance, stomatal conductance and rate of transpiration was also higher for ZnO NPs treated plants particularly in nano-primed plants. Whereas study of yield attributes showed highest cob length (14 cm), cob weight (80 g), cobs per plant (4) in ZnO NPs treated plants that was significantly higher than the both controls. Stress studies of plant samples showed that peroxidase activity was highest in plants treated with 1000 mg/L zinc salt-treated salts, both in case of priming and foliar spray. Whereas catalase activity was found highest in ZnO NPs (200 mg/L) foliar spray treated plants. Zinc content analysis of plant sample showed significantly higher amount of zinc in ZnO NPs treated corn plants. It is concluded from present study that ZnO NPs in priming treatment significantly enhanced the growth and yield attributes of corn plants through the balance of biochemical and stress indicators. Priming and foliar spray of ZnO NPs also fortified the crop with enhanced zinc content. Future study with combination of both priming and foliar spray may be further optimized. [ABSTRACT FROM AUTHOR]

Current research focused on the potential role of zinc oxide nanoparticles (ZnONPs) and potassium (K+) in mitigation of arsenic (As) toxicity in Vicia faba L. seedlings. Faba bean seedlings were grown for 30 days in potted soil. As stress curtailed root and shoot length, chlorophyll (Chl) content and net photosynthetic rate in V. faba seedlings. However, ZnONPs and K+ curtailed As stress in faba bean seedling through enhanced activity of superoxide dismutase (SOD), ascorbate peroxidase (APX), catalase (CAT) and peroxidase (POD) enzyme. Furthermore, ZnONPs and K+ significantly enhanced cysteine (Cys) content and serine acetyletransferase (SAT) activity in faba bean seedling exposed to As-toxificated soil. Application of ZnONPs and K+ curtailed superoxide ionic content and hydrogen peroxide (H2O2) accumulation in V. faba seedlings exposed to As-polluted soil. Nitric oxide (NO) content also increased in faba bean seedlings treated with ZnONPs and K+ in normal and As-polluted soil. As stress alleviation was credited to reduce As uptake in faba bean seedlings treated with synergistic application of ZnONPs and K+. It is proposed that K+ interaction with nanoparticles can be exploited at molecular level to understand the mechanisms involved in abiotic stress tolerance. Recently, Industrialisation and modern approaches have increased the level of arsenic in our environment. Higher concentration of arsenic has reduced growth of plants. This paper focuses on the role of nanoparticles in reduction of toxic effects of heavy metals. Results clearly state that nanoparticles can be used in combination with potassium silicate to enhance crop production. [ABSTRACT FROM AUTHOR]

This study was conducted to develop a protocol for in vitro shootmultiplication and callus induction of various mung bean varieties to obtain enhanced phytochemical content with the help of elicitors. For shoot multiplication, two types of explants (shoot tips and nodal tips) of three varieties of mung bean (Mung NCM-13, MgAT-7, and MgAT-4) were used. Both types of explants from in vitro and in vivo sources were cultured on the MS medium supplemented with different concentrations (0.25-3.0 mg/L, increment of 0.5 mg/L) and combinations of BAP and IBA as independent treatments. For callus induction, leaf explants (in vitro source) were cultured on MS medium supplemented with 2,4-D (1-3 mg/L) alone or in combination with BAP or NAA (0.5 and 1.0 mg/L). For the enhanced production of phenolics and glycosides, calli were cultured on MS media supplemented with zinc oxide (0.5 mg/L) and copper oxide nanoparticles (0.5 mg/L) as nano-elicitors. Results showed that in vitro explants responded better in terms of shoot length, number of shoots, and number of leaves per explant when compared to in vivo explants. Moreover, shoot tips were better than nodal explants to in vitro culturing parameters. All three varieties showed the optimized results in the MS medium supplemented with 1 mg/L BAP, while roots were produced only in cultures fortified with 1 mg/L IBA. The leaf explants of in vitro and soil-grown plantlets showed a maximum callogenic response of 90 and 80%, respectively, on MS medium supplemented with 2,4-D (3 mg/ml). Maximum phenolic content (101.4 µg of gallic acid equivalent/g) and glycoside content (34mg of amygdalin equivalent/g of plant material) was observed in the calli cultured on MS medium supplemented with 3 mg/L of 2,4-D. Furthermore, the addition of zinc oxide (0.5 mg/L) and copper oxide (0.5 mg/L) nanoparticles to the callus culture medium significantly enhanced the phenolic content of Mung NCM-13 (26%), MgAT-7 (25.6%), and MgAT-4 (22.7%). Glycosidic content was also found to be increased in Mung NCM-13 (50%), MgAT-7 (37.5%), and MgAT-4 (25%) varieties when compared to the control. It is suggested that elicitation of in vitro cultures of mung beans with nanoparticles could be an effective strategy for the enhanced production of secondary metabolites. [ABSTRACT FROM AUTHOR]

Current research work focuses on the effects of zinc oxide nanoparticles (ZnONPs) on drought-sensitive wheat variety (Faisalabad-2008) under two experimental conditions (normal irrigation and drought conditions). ZnONPs were prepared by utilizing water extract of black pepper. The formation of nanoparticles was confirmed by UV-VIS spectrophotometer, particle size analyzer, and Scanning Electron Microscope (SEM). To screen the optimum concentration of ZnONPs, a range of doses (10-2000 mg L-1) was applied to wheat seeds. Results indicated that ZnONPs (250 mg L-1) improved germination. This concentration was selected for further studies with two control treatments i.e., negative control (water) and positive control (ZnSO4 salt 250 mg L-1). ZnONPs treatment (250 mg L-1) improved germination (26.82%), shoot length (7.4%), root length (36%), fresh weight (28.6%), and dry weight (26.6%). Treatment of wheat plants with ZnONPs during drought stress increased germination percentage, root length, fresh & dry weight by 53.33, 40, 50, and 28.6 % respectively. Moreover, studies showed that chlorophyll, carotenoids and phenolic content were also increased by ZnONPs treatment by 57.4, 77.27, and 25% respectively as compared to control. Malondialdehyde content was significantly lower in nanoparticles treated plants as compared to Zn salt-treated plants. Zn content of seeds was also significantly higher for ZnONPs treated plants. It suggests the potential of ZnONPs designed by the green method as a nano fertilizer in ameliorating drought stress conditions. [ABSTRACT FROM AUTHOR]