Mulberry based zinc nano-particles mitigate salinity induced toxic effects and improve the grain yield and zinc bio-fortification of wheat by improving antioxidant activities, photosynthetic performance, and accumulation of osmolytes and hormones

Simultaneous alleviation of antimony toxicity in rice and in-Vitro bio-accessibility by using biochar and seaweed based fertilizer blend

Antimony (Sb) toxicity is a significant threat to crop production and humans. Its concentration is increasing in soil and water due to human activities which needs dire attention to address this challenge. Biochar is a promising amendment to remediate polluted soils, however, its role in mitigating the toxic impacts of Sb on plants is still unclear. Seaweed-based fertilizer (SBF) has shown appreciable results in improving plant performance, however, its role against metal/metalloids toxicity has not been studied yet. Therefore, this study tested the impacts of BC and SBF in mitigating the harmful effects of Sb on rice. The study was carried out with the following treatments; control, Sb stress (600 mg kg-1), Sb stress + biochar (2%), Sb stress + seaweed-based fertilizer (SBF: 2%), and Sb stress + BC (1%) and SBF (1%). The results showed that Sb toxicity adversely affected rice growth and productivity by impeding photosynthetic pigments, leaf relative water contents, increasing production of oxidative stress biomarkers (electrolyte leakage: EL, hydrogen peroxide: H2O2, malondialdehyde: MDA), and accumulation of Sb in plant parts. Contrarily, BC and SBF blends mitigated Sb-induced growth and yield damages in rice by improving photosynthetic efficiency, osmolyte synthesis, nutrient uptake, soil enzymatic activity, and antioxidant activities. Moreover, BC and SBF blend also reduced the bio-accessible Sb concentration (95.63%), bio-accessibility of Sb (25.40%), Sb transport coefficient (35.70%) and soil Sb antimony concentration (52.74%). Given these findings, the co-application of BC and SBF showed a profound improvement in rice yield by regulating photosynthetic performance, antioxidant activities, oxidative stress markers, antioxidant activities, and soil properties.

Foliar application of zinc oxide (ZnO) nanoparticles ameliorates growth, yield traits, osmolytes, cell viability, and antioxidant system of Brassica juncea (L.) Czern. grown in lead (Pb) stress

Heavy metal stress is one of the exorbitant problems faced by plants. Lead (Pb) stress is one of the prevalent stressors in agricultural fields. Nanofertilizers are being currently employed for mitigating heavy metal stress in plants. This study assessed the suitability of zinc oxide nanoparticles (ZnONPs) in ameliorating Pb stress in Brassica juncea (L.) Czern. var. Pusa Jagannath. The tested plants were grown in pots using a randomized block design, placed in herbal garden of Jamia Hamdard and treated with different amounts of Pb and nanozinc viz. control (T0), 250 ppm ZnONPs (T1), 500 ppm ZnONPs (T2), 1000 ppm ZnONPs (T3), 250 μM Pb (T4), 500 μM Pb (T5), and their combinations i.e. 250 μM Pb and 500 ppm ZnONPs (T6), 500 μM Pb and 500 ppm ZnONPs (T7), 250 μM Pb and 1000 ppm ZnONPs (T8) and 500 μM Pb and 1000 ppm ZnONPs (T9). The plants were tested for variations in morpho-physiological parameters, yield traits, biochemical attributes, antioxidant enzyme activity, and cell viability using confocal microscopy. Maximum dose of Pb (500 μM) decreased morphological and yield traits such as leaf area (-51%), shoot length (-17%), root length (-34%), number of seeds per plant (-73%), weight of the seeds (-35%), pod number (-47%), shoot and root fresh weight by -63% and -56%, along with reduction in total chlorophyll (-12%), carotenoid (-38%) content, nitrate reductase (-64%) activity, total soluble protein (-40%), total soluble sugar (-31%) and antioxidant enzymes (SOD, CAT and APX by -14%, -4%, -15% respectively) in comparison to control. Stress markers like proline (195%) and MDA (266%) were elevated in Pb-treated plants.The increased level of total phenol content (89%) and total flavonoid content (478%) was also noted in Pb treated plants which acted as non-enzymatic antioxidant defense. The foliar application of ZnONPs (1000 ppm) was found to be effective in ameliorating Pb induced stress, as depicted by the increases in root length (43%), shoot length (38%), pod number (46%), seed weight (70%), number of seeds per plant (105%), chlorophyll content (41%), carotenoid content (28%), total soluble protein content (20%), and nitrate reductase activity (59%) in comparison to control. When ZnONPs (1000 ppm) was supplemented in Pb (250 μM) treated plants, antioxidant enzymes (SOD and CAT increased by 83%, and APX by 75%) and stress markers such as proline amplified by 387%, and total soluble sugar (61%), with respect to control. ZnONPs also improved the cell viability under Pb stress as revealed by confocal microscopy. In summary, foliar spray of ZnONPs proved effective in mitigating the Pb-induced stress in mustard which could be an effective strategy to alleviate the deleterious effects of Pb stress (500 μM) in mustard plants so as to realize its sustainable production under abiotic stress.

Biochar co-compost increases the productivity of Brassica napus by improving antioxidant activities and soil health and reducing lead uptake

Lead (Pb) is a serious toxic metal without any beneficial role in the biological system. Biochar (BC) has emerged as an excellent soil amendment to mitigate Pb toxicity. The impact of BC co-compost (BCC) in mitigating the toxic impacts of Pb has not been studied yet. Therefore, this study aimed to evaluate the potential of BC and BCC in improving the growth, physiological, and biochemical traits of Brassica napus and soil properties and reducing health risks (HR). The study was comprised of different Pb concentrations (control and 100 mg kg-1) and organic amendments (control, BC, compost, and BCC). The results indicated that Pb stress reduced the growth, photosynthetic pigments, seed yield, and oil contents by increasing hydrogen peroxide (H2O2) production and Pb uptake and accumulation in plant tissues and decreasing photosynthetic pigment and nutrient availability. The application of BCC alleviated the adverse impacts of Pb and improved seed production (40.24%) and oil yield (11.06%) by increasing chlorophyll a (43.18%) and chlorophyll b (25.58%) synthesis, relative water content (23.89%), total soluble protein (TSP: 23.14%), free amino acids (FAA: 26.47%), proline (30.98%), APX (40.90%), CAT (32.79%), POD (24.93%), and SOD (33.30%) activity. Biochar co-compost-mediated increase in seed and oil yield was also linked with a reduced accumulation of Pb in plant parts and soil Pb availability and improved the soil-available phosphorus, potassium, total nitrogen, soil organic carbon (SOC), and microbial biomass carbon (MBC). Furthermore, BCC also reduced the bioaccumulation concentration, daily metal intake, hazard index, and target hazard quotient. In conclusion, application of BCC can increase the growth, yield, and oil contents of Brassica napus by improving the physiological and biochemical traits and soil properties and reducing the Pb uptake.

Zinc oxide nanoparticle biofortification of lentil seedlings enhances plant growth and zinc bioavailability in rats

This study aimed to evaluate the potential of zinc oxide nanoparticles (ZnO NPs) in the biofortification of lentil seedlings and subsequently improve the Zn status in rats. In the first phase of the study, the effects of various ZnO NPs concentrations (0, 10, 20, 40, 80, and 160 ppm) on the lentil growth, Zn accumulation, and other physiological parameters were investigated. Subsequently, the rats were fed ZnO NP-biofortified lentil seedlings (20 and 160 ppm) to assess their impact on animal health and Zn status. The results highlighted a concentration-dependent response of lentil seedlings to ZnO NPs, with optimal growth observed at 20 ppm, whereas higher concentrations inhibited lentil growth. Pigment and biochemical analyses revealed a complex interplay between chlorophyll, carotenoids, soluble sugars, and proteins with distinct responses to nanoparticle concentrations. Elevated levels of hydrogen peroxide and malondialdehyde of lentil seedlings at high concentrations of ZnO NPs suggest oxidative stress, countered by the upregulation of antioxidant enzymes and increased phenolic compounds. On the other hand. animal studies have showed that ZnO NP-biofortified lentil seedlings enhance serum zinc and magnesium levels in rats without affecting body weight. While serum triglyceride levels of rats decreased in both treatment groups, an elevation in creatinine and a marked increase in aspartate aminotransferase (AST) levels were observed at a higher ZnO NP concentration (160 ppm), indicative of potential kidney and liver stress. Paradoxically, serum iron levels were lower in all groups consuming lentil seedlings than in the control group, suggesting a potential interaction between lentil components and iron metabolism. These findings suggest that ZnO NP-biofortified lentils may be a promising approach to enhance Zn nutrition; however, further investigation is needed to optimize ZnO NPs concentration and assess long-term safety.

Revitalizing maize growth and yield in water-limited environments through silicon and zinc foliar applications

Maize is an economically vital cereal crop. However, water deficiency can severely impact its productivity. Thus, it is necessary to implement an essential approach to increase maize yield while navigating the limitations imposed by scarce water supplies. The present study aimed to investigate whether foliar applications of silicon (Si) and zinc (Zn) could mitigate the adverse effects of water deficiency and improve maize growth and yield. Field experiments were conducted in Egypt during two growing seasons (2021-2022) under three irrigation regimes: full irrigation (ET0), moderate stress (ET1), and severe stress (ET2). The treatments comprised foliar sprays of Si, Zn, Si + Zn, and water control. Phenological, growth, physiological, chemical, and yield-related traits were assessed. Results showed that adequate irrigation (ET0) enhanced most parameters compared to water stress treatments. Under ET0, the combined silicon and zinc treatment resulted in the highest values for plant height, leaf area, chlorophyll content, grains per ear, kernel weight, ear size, and yield compared to other foliar treatments. Under drought stress (ET1, ET2), Si + Zn applications maintained superiority in mitigating yield losses. Proline accumulation was highest under severe stress (ET2) in the absence of foliar sprays, indicating greater drought impacts. Correlation analysis revealed positive associations of grain yield with ear size, leaf area, kernel weight, and biological yield. Cluster analysis separated irrigation regimes and visualized the consistently beneficial effects of Si + Zn across all water levels. Overall, the results demonstrate the synergistic potential of Si and Zn supplementation to sustain maize performance and yields under varying water availability.

Impact of nanopollution on plant growth, photosynthesis, toxicity, and metabolism in the agricultural sector: An updated review

Nanotechnology provides distinct benefits to numerous industrial and commercial fields, and has developed into a discipline of intense interest to researchers. Nanoparticles (NPs) have risen to prominence in modern agriculture due to their use in agrochemicals, nanofertilizers, and nanoremediation. However, their potential negative impacts on soil and water ecosystems, as well as plant growth and physiology, have caused concern for researchers and policymakers. Concerns have been expressed regarding the ecological consequences and toxicity effects associated with nanoparticles as a result of their increased production and usage. Moreover, the accumulation of nanoparticles in the environment poses a risk, not only because of the possibility of plant damage but also because nanoparticles may infiltrate the food chain. In this review, we have documented the beneficial and detrimental effects of NPs on seed germination, shoot and root growth, plant biomass, and nutrient assimilation. Nanoparticles exert toxic effects by inducing ROS generation and stimulating cytotoxic and genotoxic effects, thereby leading to cell death in several plant species. We have provided possible mechanisms by which nanoparticles induce toxicity in plants. In addition to the toxic effects of NPs, we highlighted the importance of nanomaterials in the agricultural sector. Thus, understanding the structure, size, and concentration of nanoparticles that will improve plant growth or induce plant cell death is essential. This updated review reveals the multifaceted connection between nanoparticles, soil and water pollution, and plant biology in the context of agriculture.

Nano-enabled seed treatment: A new and sustainable approach to engineering climate-resilient crops

Under a changing climate, keeping the food supply steady for an ever-increasing population will require crop plants adapted to environmental fluctuations. Genetic engineering and genome-editing approaches have been used for developing climate-resilient crops. However, genetically modified crops have yet to be widely accepted, especially for small-scale farmers in low-income countries and some societies. Nano-priming (seed exposure to nanoparticles, NPs) has appeared as an alternative to the abovementioned techniques. This technique improves seed germination speed, promotes seedlings' vigor, and enhances plant tolerance to adverse conditions such as drought, salinity, temperature, and flooding, which may occur under extreme weather conditions. Moreover, nano-enabled seed treatment can increase the disease resistance of crops by boosting immunity, which will reduce the use of pesticides. This unsophisticated, farmer-available, cost-effective, and environment-friendly seed treatment approach may help crop plants fight climate change challenges. This review discusses the previous information about nano-enabled seed treatment for enhancing plant tolerance to abiotic stresses and increasing disease resistance. Current knowledge about the mechanisms underlying nanomaterial-seed interactions is discussed. To conclude, the review includes research questions to address before this technique reaches its full potential.

Soil acidification and salinity: the importance of biochar application to agricultural soils

Soil acidity is a serious problem in agricultural lands as it directly affects the soil, crop production, and human health. Soil acidification in agricultural lands occurs due to the release of protons (H+) from the transforming reactions of various carbon, nitrogen, and sulfur-containing compounds. The use of biochar (BC) has emerged as an excellent tool to manage soil acidity owing to its alkaline nature and its appreciable ability to improve the soil's physical, chemical, and biological properties. The application of BC to acidic soils improves soil pH, soil organic matter (SOM), cation exchange capacity (CEC), nutrient uptake, microbial activity and diversity, and enzyme activities which mitigate the adverse impacts of acidity on plants. Further, BC application also reduce the concentration of H+ and Al3+ ions and other toxic metals which mitigate the soil acidity and supports plant growth. Similarly, soil salinity (SS) is also a serious concern across the globe and it has a direct impact on global production and food security. Due to its appreciable liming potential BC is also an important amendment to mitigate the adverse impacts of SS. The addition of BC to saline soils improves nutrient homeostasis, nutrient uptake, SOM, CEC, soil microbial activity, enzymatic activity, and water uptake and reduces the accumulation of toxic ions sodium (Na+ and chloride (Cl-). All these BC-mediated changes support plant growth by improving antioxidant activity, photosynthesis efficiency, stomata working, and decrease oxidative damage in plants. Thus, in the present review, we discussed the various mechanisms through which BC improves the soil properties and microbial and enzymatic activities to counter acidity and salinity problems. The present review will increase the existing knowledge about the role of BC to mitigate soil acidity and salinity problems. This will also provide new suggestions to readers on how this knowledge can be used to ameliorate acidic and saline soils.

How Does Zinc Improve Salinity Tolerance? Mechanisms and Future Prospects

Salinity stress (SS) is a serious abiotic stress and a major constraint to agricultural productivity across the globe. High SS negatively affects plant growth and yield by altering soil physio-chemical properties and plant physiological, biochemical, and molecular processes. The application of micronutrients is considered an important practice to mitigate the adverse effects of SS. Zinc (Zn) is an important nutrient that plays an imperative role in plant growth, and it could also help alleviate the effects of salt stress. Zn application improves seed germination, seedling growth, water uptake, plant water relations, nutrient uptake, and nutrient homeostasis, therefore improving plant performance and saline conditions. Zn application also protects the photosynthetic apparatus from salinity-induced oxidative stress and improves stomata movement, chlorophyll synthesis, carbon fixation, and osmolytes and hormone accumulation. Moreover, Zn application also increases the synthesis of secondary metabolites and the expression of stress responsive genes and stimulates antioxidant activities to counter the toxic effects of salt stress. Therefore, to better understand the role of Zn in plants under SS, we have discussed the various mechanisms by which Zn induces salinity tolerance in plants. We have also identified diverse research gaps that must be filled in future research programs. The present review article will fill the knowledge gaps on the role of Zn in mitigating salinity stress. This review will also help readers to learn more about the role of Zn and will provide new suggestions on how this knowledge can be used to develop salt tolerance in plants by using Zn.

Green Synthesized Silver Nanoparticles: A Novel Approach for the Enhanced Growth and Yield of Tomato against Early Blight Disease

Tomato plants are among the most widely cultivated and economically important crops worldwide. Farmers' major challenge when growing tomatoes is early blight disease caused by Alternaria solani, which results in significant yield losses. Silver nanoparticles (AgNPs) have gained popularity recently due to their potential antifungal activity. The present study investigated the potential of green synthesized silver nanoparticles (AgNPs) for enhancing the growth and yield of tomato plants and their resistance against early blight disease. AgNPs were synthesized using leaf extract of the neem tree. Tomato plants treated with AgNPs showed a significant increase in plant height (30%), number of leaves, fresh weight (45%), and dry weight (40%) compared to the control plants. Moreover, the AgNP-treated plants exhibited a significant reduction in disease severity index (DSI) (73%) and disease incidence (DI) (69%) compared to the control plants. Tomato plants treated with 5 and 10 ppm AgNPs reached their maximum levels of photosynthetic pigments and increased the accumulation of certain secondary metabolites compared to the control group. AgNP treatment improved stress tolerance in tomato plants as indicated by higher activities of antioxidant enzymes such as PO (60%), PPO (65%), PAL (65.5%), SOD (65.3%), CAT (53.8%), and APX (73%). These results suggest that using green synthesized AgNPs is a promising approach for enhancing the growth and yield of tomato plants and protecting them against early blight disease. Overall, the findings demonstrate the potential of nanotechnology-based solutions for sustainable agriculture and food security.

Bio-Fabrication of ZnONPs from Alkalescent Nucleoside Antibiotic to Control Rice Blast: Impact on Pathogen (Magnaporthe grisea) and Host (Rice)

In the traditional method of the bio-fabrication of zinc oxide nanoparticles (ZnONPs), bacterial strains face metal toxicity and antimicrobial action. In the current study, an alkalescent nucleoside antibiotic was mixed with zinc hexanitrate to fabricate the ZnONPs. An integrated approach of DIAION HP-20 macroporous resin and sephadex LH-20 column chromatography was adopted to separate and purify alkalescent nucleoside AN03 from Streptomyces koyanogensis. Alkalescent nucleoside was confirmed by the Doskochilova solvent system. The bio-fabricated ZnONPs were characterized by using Fourier transform infrared (FTIR), X-ray diffraction (XRD), and transmission electron microscopy (TEM) analyses. The XRD spectrum and the TEM images confirmed the crystallinity and the spherical shape of the ZnONPs with an average size of 22 nm. FTIR analysis showed the presence of functional groups, which confirmed the bio-fabrication of ZnONPs from alkalescent nucleoside ANO3. In-vitro studies showed that 75 μg/mL of ZnONPs had a strong inhibitory zone (28.39 mm) against the Magnaporthe grisea and significantly suppressed the spore germination. SEM and TEM observations respectively revealed that ZnONPs caused breakage in hyphae and could damage the cells of M. grisea. Greenhouse experiments revealed that the foliar spray of ZnONPs could control the rice blast disease by 98%. Results also revealed that ZnONPs had positive effects on the growth of the rice plant. The present study suggested that ZnONPs could be fabricated from microbe-derived nucleoside antibiotics without facing the problems of metal toxicity and antimicrobial action, thus overcoming the problem of pathogen resistance. This could be a potent biocontrol agent in rice blast disease management.