Substitution of fishmeal: Highlights of potential plant protein sources for aquaculture sustainability.

High protein content, excellent amino acid profile, absence of anti-nutritional factors (ANFs), high digestibility and good palatability of fishmeal (FM), make it a major source of protein in aquaculture. Naturally derived FM is at risk due to an increase in its demand, unsustainable practices, and price. Thus, there is an urgent need to find affordable and suitable protein sources to replace FM. Plant protein sources are suitable due to their widespread availability and low cost. However, they contained certain ANFs, deficiency of some amino acids, low nutrient bioavailability and poor digestibility due to presence of starch and fiber. These unfavourable characteristics make them less suitable for feed as compared to FM. Thus, these potential challenges and limitations associated with various plant proteins have to be overcome by using different methods, i.e. enzymatic pretreatments, solvent extraction, heat treatments and fermentation, that are discussed briefly in this review. This review assessed the impacts of plant products on growth performance, body composition, flesh quality, changes in metabolic activities and immune response of fishes. To minimize the negative effects and to enhance nutritional value of plant products, beneficial functional additives such as citric acid, phytase and probiotics could be incorporated into the plant-based FM. Interestingly, these additives improve growth of fishes by increasing digestibility and nutrient utilization of plant based feeds. Overall, this review demonstrated that the substitution of fishmeal by plant protein sources is a plausible, technically-viable and practical option for sustainable aquaculture feed production.

Evaluation of growth, nutrient absorption, body composition and blood indices under dietary exposure of iron oxide nanoparticles in Common carp (Cyprinus carpio).

The bioavailability, small size and direct absorption in the blood, make nanoparticles (NPs) a remarkable feed additive in the aquaculture industry. Therefore, dietary iron oxide nanoparticles (Fe2 O3 -NPs) were used to examine their effects on growth, nutrient absorption, body composition and blood indices in Cyprinus carpio (Common carp) fingerlings. Healthy C. carpio fingerlings (n = 270) were fed with six canola meal based experimental diets (D1-control, D2, D3, D4, D5, D6) supplemented with 0, 10, 20, 30, 40 and 50 mg/kg Fe2 O3 -NPs respectively. A total of 15 fingerlings (average initial weight 5.51 ± 0.04 g/fish) were kept in triplicates for 70 days. The results indicated that maximum growth performance, apparent digestibility coefficient, body composition and haematological parameters were observed in 40 mg/kg Fe2 O3 -NPs supplementation. All the experimental diets were significantly improved (p < 0.05) in all the above parameters than control diet. In the present research, the recommended dosage of Fe2 O3 -NPs as dietary supplement is 40 mg/kg for improving the growth, nutrient absorption, body composition and haematological indices in C. carpio fingerlings. Hence, this study demonstrates the potential of NPs to improve the health of fish.

Characterization for optimizing the integrated management of solid waste for energy recovery and circular economy.

Municipal solid waste (MSW) management poses a significant environmental challenge in municipalities across developing nations worldwide. Our studies were focused on characterizing the waste and analyzing the chemical properties of mixed waste fractions to assess their potential for waste-to-energy conversion. The objective of our study was to scrutinize the existing state of the MSW management system and gauge its waste generation rates. Specific ASTM methods were employed to carry out both physical and chemical characterizations. The outcomes reveal that the city generates a daily volume of 1155 tons of domestic solid waste (DSW), translating to a generation rate of 0.51 kg-1 capita-1 day-1. When analyzed by source, organic matter emerged as the predominant constituent, accounting for 73.74% of the waste, followed by combustible content waste at 15.17%. The moisture content of MSW ranged between 26 and 58% throughout the seasons, while volatile solids varied from 22.35 to 99.74%. Among the components screened, carbon and oxygen stood out as the dominant elements. The calorific values encompassed a broad range, ranging from 14.87 MJ kg-1 for leather waste to a substantial 25,629.27 MJ kg-1 for organic waste. To alleviate the escalating burden of increasing solid waste generation, alternative treatment approaches were recommended. These include composting, biomethane plants, the establishment of recycling facilities, and the enhancement of existing landfill sites to scientifically designed landfills. In summary, the findings from this study provide valuable insights for regulatory bodies and municipal authorities. These insights can guide the formulation of policies concerning waste sampling, characterization, segregation, and the implementation of education and awareness campaigns.

Co-application of copper nanoparticles and metal tolerant Bacillus sp. for improving growth of spinach plants in chromium contaminated soil.

Chromium (Cr) is classified as a toxic metal as it exerts harmful effects on plants and human life. Bacterial-assisted nano-phytoremediation is an emerging and environment friendly technique that can be used for the detoxification of such pollutants. In current study, pot experiment was conducted in which spinach plants were grown in soil containing chromium (0, 5, 10, 20 mgkg-1) and treated with selected strain of Bacillus sp. and Cu-O nanoparticle (CuONPs). Data related to plant's growth, physiological parameters, and biochemical tests was collected and analyzed using an appropriate statistical test. It was observed that under chromium stress, all plant's growth parameters were significantly enhanced in response to co-application of CuONPs and Bacillus sp. Similarly, higher levels of catalase, superoxide dismutase, malondialdehyde, and hydrogen peroxide were also observed. However, contents of anthocyanin, carotenoid, total chlorophyll, chlorophyll a & b, were lowered under chromium stress, which were raised in response to the combined application of CuONPs and Bacillus sp. Moreover, this co-application has significant positive effect on total soluble protein, free amino acid, and total phenolics. From this study, it was evident that combined application of Bacillus sp. and CuONP alleviated metal-induced toxicity in spinach plants. The findings from current study may provide new insights for agronomic research for the utilization of bacterial-assisted nano-phytoremediation of contaminated sites.

Effect of phosphorus sources on growth and cadmium accumulation in wheat under different soil moisture levels.

Both cadmium (Cd) toxicity and water limited stress in crop plants are serious concerns worldwide while little is known about the impact of various phosphorus (P) sources on Cd accumulation in cereals especially under water limited stress. A study was conducted to explore the efficiency of three frequently available P fertilizers on Cd accumulation in wheat under different soil moisture levels. Three different P sources including diammonium phosphate (DAP), single super phosphate (SSP), and nitrophos (NP) were applied in the soil with three levels (0, 50 and 100 mg/kg). The drought stress was applied to half treatments during the latter growth stages of wheat and plants were harvested at maturity. The results demonstrated that water-limited stress decreased the growth and yield of plants than respective treatments without water stress. P supply increased the growth of wheat irrespective of water-limited stress. The effect on growth and yield varied with the sources and levels of P and maximum effects was observed in DAP treatment (100 mg/kg). The P amendments enhanced the leaf photosynthesis and activities of SOD, POD, CAT and decreased the leaf oxidative burst. Water limited stress enhanced the Cd concentrations in shoots, roots, and grains whereas P amendments minimized the Cd concentrations and enhanced the P concentrations in these parts of plants. The results obtained demonstrated that P supply in the form of DAP might be effective in minimization of Cd in grains and can be used for safe cultivation of metal-contaminated soils.

Recent Advancements and Development in Nano-Enabled Agriculture for Improving Abiotic Stress Tolerance in Plants.

Abiotic stresses, such as heavy metals (HMs), drought, salinity and water logging, are the foremost limiting factors that adversely affect the plant growth and crop productivity worldwide. The plants respond to such stresses by activating a series of intricate mechanisms that subsequently alter the morpho-physiological and biochemical processes. Over the past few decades, abiotic stresses in plants have been managed through marker-assisted breeding, conventional breeding, and genetic engineering approaches. With technological advancement, efficient strategies are required to cope with the harmful effects of abiotic environmental constraints to develop sustainable agriculture systems of crop production. Recently, nanotechnology has emerged as an attractive area of study with potential applications in the agricultural science, including mitigating the impacts of climate change, increasing nutrient utilization efficiency and abiotic stress management. Nanoparticles (NPs), as nanofertilizers, have gained significant attention due to their high surface area to volume ratio, eco-friendly nature, low cost, unique physicochemical properties, and improved plant productivity. Several studies have revealed the potential role of NPs in abiotic stress management. This review aims to emphasize the role of NPs in managing abiotic stresses and growth promotion to develop a cost-effective and environment friendly strategy for the future agricultural sustainability.

Corrigendum: Role of Promising Secondary Metabolites to Confer Resistance Against Environmental Stresses in Crop Plants: Current Scenario and Future Perspectives.

[This corrects the article DOI: 10.3389/fpls.2022.881032.].

Effect of different seed priming agents on chromium accumulation, oxidative defense, glyoxalase system and mineral nutrition in canola (Brassica napus L.) cultivars.

The present experiment was conducted to appraise the role of different seed priming agents in circumventing the negative impact of chromium (Cr) toxicity on canola plants. Chromium toxicity resulted in significant decline in photosynthetic pigments and growth attributes of two canola cultivars (Puriga and MS-007). Cr toxicity also resulted in higher oxidative stress mirrored as greater accumulation of hydrogen peroxide (H2O2) superoxide radical (O2•‒), electrolyte leakage (EL) and malondialdehyde (MDA). Further, lipoxygenase enzyme activity that catalyzes the peroxidation of membrane lipids was also enhanced due to Cr toxicity. Canola plants also manifested impaired methylglyoxal (MG) detoxification due to the downregulation of glyoxalase enzymes (GlyI and II) under Cr stress. Seed priming treatments viz. osmo-priming with calcium chloride (CaCl2) and hormonal priming with salicylic acid (SA) remarkably improved growth and chlorophyll content in both canola cultivars under Cr toxicity as compared to other priming treatments such as hydro-priming, redox priming (H2O2) and chemical priming (Se; selenium). Moreover, CaCl2 and SA seed priming also resulted in lower oxidative stress and improved enzymatic (SOD, POD, CAT, APX, GR, GST) and non-enzymatic (GSH, phenolics, flavonoids, proline) antioxidant system of both cultivars under Cr toxicity. Further, hormonal and osmo-priming strengthened glyoxalase and antioxidant systems, thus improving reactive oxygen species (ROS) and MG detoxification. In this background, the cultivar Puriga is considered Cr tolerant as it exhibited better growth and lesser oxidative stress in both seed priming and non-primed conditions under Cr toxicity than cv. MS-007.

Foliar spray of silicon nanoparticles improved the growth and minimized cadmium (Cd) in wheat under combined Cd and water-limited stress.

The effects of foliar supply of silicon nanoparticles (Si-NPs) on growth, physiology, and cadmium (Cd) uptake by wheat (Triticum aestivum L.) were examined in different soil moisture levels. Seeds were sown in soil containing excess Cd (7.67 mg kg-1) and Si-NPs were applied through foliar dressing with various levels (0, 25, 50, 100 mg L-1) at different time intervals during growth period. Initially, all pots were irrigated with normal moisture level (70% water-holding capacity) and two moisture levels (35%, 70% WHC) were initiated after 6 weeks of plant growth for remaining growth duration and harvesting was done after 124 days of sowing. The results demonstrated the lowest plant growth, yield, and chlorophyll concentrations while the highest oxidative stress and Cd concentrations in plant tissues in water-stressed control (35% WHC) followed by normal control (75% WHC). Si-NPs enhanced the growth, photosynthesis, leaf defense system, and Si concentrations in tissues while minimized the Cd in wheat parts particularly in grains either soil normal or water-stressed conditions. Of the foliar spray, 100 mg L-1 of Si-NPs showed the best results with respect to growth, Cd and Si uptake by plants, and soil post-harvest bioavailable Cd irrespective of soil water levels. In grain, Cd concentration was below threshold limit (0.2 mg kg-1) for cereals in 100-mg kg-1 Si-NPs treatment irrespective of soil water levels. Si-NPs foliar dressing under Cd and water-limited stress might be an effective strategy in increasing growth, yield, and decreasing Cd concentration in wheat grains under experimental conditions. Thus, foliar dressing of Si-NPs minimized the Cd risk in food crops and NPs entry to surroundings, which might be possible after harvesting of crops in soil-applied NPs.

Elevated ozone phytotoxicity ameliorations in mung bean {Vigna radiata (L.) Wilczek} by foliar nebulization of silicic acid and ascorbic acid.

The present work provides an insight into the development of biochemical adaptations in mung beans against ozone (O3) toxicity. The study aims to explore the O3 stress tolerance potential of mung bean genotypes under exogenous application of growth regulators. The seeds of twelve mung bean genotypes were grown in plastic pots under controlled conditions in the glasshouse. Six treatments, control (ambient ozone level 40-45 ppb), ambient O3 with ascorbic acid, ambient ozone with silicic acid, elevated ozone (120 ppb), elevated O3 with ascorbic acid (10 mM), and elevated ozone with silicic acid (0.1 mM) were applied. The O3 fumigation was carried out using an O3 generator. The results revealed that ascorbic acid and silicic acid application decreased the number of plants with foliar O3 injury symptoms in different degrees, i.e., zero, first, second, third, and fourth degrees; whereas 0-4 degree symptoms represent, no symptoms, symptoms occupying < 1/4, 1/4-1/2, 1/2-3/4, and > 3/4 of the total foliage area, respectively. Application of ascorbic acid and silicic acid also prevented the plants from the negative effects of O3 in terms of fresh as well as dry matter production, leaf chlorophyll, carotenoids, soluble proteins and ascorbic acid, proline, and malondialdehyde (MDA) contents. Overall, silicic acid application proved more effective in reducing the negative effects of O3 on mung bean genotypes as compared to that of the ascorbic acid. Three mung bean genotypes (NM 20-21, NM-2006, and NM-2016) were identified to have a better adaptive mechanism for O3 toxicity tolerance and may be good candidates for future variety development programs.

Application of Cerium Dioxide Nanoparticles and Chromium-Resistant Bacteria Reduced Chromium Toxicity in Sunflower Plants.

The continuous increase in the heavy metals concentration in the soil due to anthropogenic activities has become a global issue. The chromium, especially hexavalent chromium, is highly toxic for living organisms due to high mobility, solubility, and carcinogenic properties. Considering the beneficial role of nanoparticles and bacteria in alleviating the metal stress in plants, a study was carried out to evaluate the role of cerium dioxide (CeO2) nanoparticles (NPs) and Staphylococcus aureus in alleviating the chromium toxicity in sunflower plants. Sunflower plants grown in chromium (Cr) contaminated soil (0, 25, and 50 mg kg-1) were treated with CeO2 nanoparticles (0, 25, and 50 mg L-1) and S. aureus. The application of Cerium Dioxide Nanoparticles (CeO2 NPs) significantly improved plant growth and biomass production, reduced oxidative stress, and enhanced the enzymatic activities in the sunflower plant grown under chromium stress. The application of S. aureus further enhanced the beneficial role of nanoparticles in alleviating metal-induced toxicity. The maximum improvement was noted in plants treated with both nanoparticles and S. aureus. The augmented application of CeO2 NPs (50 mg l-1) at Cr 50 mg kg-1 increased the chl a contents from 1.2 to 2.0, chl b contents 0.5 to 0.8 and mg g-1 FW, and decreased the leakage of the electrolyte from 121 to 104%. The findings proved that the application of CeO2 nanoparticles and S. aureus could significantly ameliorate the metal-induced stress in sunflower plants. The findings from this study can provide new horizons for research in the application of nanoparticles in phytoremediation and bioremediation.

Role of Promising Secondary Metabolites to Confer Resistance Against Environmental Stresses in Crop Plants: Current Scenario and Future Perspectives.

Plants often face incompatible growing environments like drought, salinity, cold, frost, and elevated temperatures that affect plant growth and development leading to low yield and, in worse circumstances, plant death. The arsenal of versatile compounds for plant consumption and structure is called metabolites, which allows them to develop strategies to stop enemies, fight pathogens, replace their competitors and go beyond environmental restraints. These elements are formed under particular abiotic stresses like flooding, heat, drought, cold, etc., and biotic stress such as a pathogenic attack, thus associated with survival strategy of plants. Stress responses of plants are vigorous and include multifaceted crosstalk between different levels of regulation, including regulation of metabolism and expression of genes for morphological and physiological adaptation. To date, many of these compounds and their biosynthetic pathways have been found in the plant kingdom. Metabolites like amino acids, phenolics, hormones, polyamines, compatible solutes, antioxidants, pathogen related proteins (PR proteins), etc. are crucial for growth, stress tolerance, and plant defense. This review focuses on promising metabolites involved in stress tolerance under severe conditions and events signaling the mediation of stress-induced metabolic changes are presented.

Green synthesis and characterization of silver nanoparticles from Acacia nilotica and their anticancer, antidiabetic and antioxidant efficacy.

Both cancer and diabetes mellitus are serious health issues, accounting more than 11 million deaths worldwide annually. Targeted use of plant-mediated nanoparticles (NPs) in treatment of ailments has outstanding results due to their salient properties. The current study was designed to investigate the safe production of silver nanoparticles (AgNPs) from Acacia nilotica. Different concentrations of AgNO3 were tested to optimize the protocol for the synthesis of AgNPs from the bark extract. It was demonstrated that 0.1 M and 3 mM were found to be the optimum concentrations for the synthesis of AgNPs. Standard characterization techniques such as UV-vis spectrophotometry, SEM, SEM-EDX micrograph, spot analysis, elemental mapping and XRD were used for the conformation of biosynthesis of AgNPs. Absorption spectrum of plant-mediated AgNPs under UV-vis spectrophotometer showed a strong peak at 380 nm and 420 nm for AgNPs synthesized at 0.1 M and 3 mM concentration of salt. The SEM results showed that AgNPs were present in variable shapes within average particle size ranging from (20-50 nm). Anticancer, antidiabetic and antioxidant potential of green AgNPs was investigated and they showed promising results as compared to the positive and negative controls. Hence, AgNPs were found potent therapeutic agent against the human liver cancer cell lines (HepG2), strong inhibitor for α-glucosidase enzyme activity and scavenging agent against free radicals that cause oxidative stress. Further studies are however needed to confirm the molecular mechanism and biochemical reactions responsible for the anticancer and antidiabetic activities of the particles.

Combined effects of green manure and zinc oxide nanoparticles on cadmium uptake by wheat (Triticum aestivum L.).

Cadmium (Cd) toxicity in agricultural soils is serious concern these days which needs continuous attention. Little is known about the combined use of berseem and/or maize residues soil applied as a green manure alone or along with foliar dressing of zinc oxide nanoparticles (ZnONPs) on Cd accumulation in wheat (Triticum aestivum L.). A pot experiment under ambient conditions with wheat grown in Cd-contaminated soil was performed after soil applied different green manure amendments and foliar dressing of ZnONPs was done during plant growth and plants were harvested at full maturity. Compared with control, plant growth attributes and biomass of above ground parts substantially increased with applied amendments being maximum with combined use of ZnONPs + B75 (berseem residue, 75 mg/kg) followed by ZnONPs + M75 (maize residue, 75 mg/kg). All the treatments improved the leaf chlorophyll contents and improved the leaf antioxidant enzyme activities thereby reduced the leaf electrolyte leakage. The Cd accumulation in roots and aboveground parts of the wheat was reduced especially in ZnONPs + B75 followed by ZnONPs + M75. The higher rate of soil applied amendments along with NPs minimized the available Cd in soil extracts but soil post-harvest pH was not much affected by the applied amendments. In conclusion, incorporation of berseem and maize residues as a green manure applied in Cd-contaminated soil combined with foliar NPs may decrease Cd phytoavailability and its accumulation in wheat grains. However, substantial field studies are required under various environmental conditions before final recommendations at field levels.

Effects of nanoparticles on trace element uptake and toxicity in plants: A review.

Agricultural soils are receiving higher inputs of trace elements (TEs) from anthropogenic activities. Application of nanoparticles (NPs) in agriculture as nano-pesticides and nano-fertilizers has gained rapid momentum worldwide. The NPs-based fertilizers can facilitate controlled-release of nutrients which may be absorbed by plants more efficiently than conventional fertilizers. Due to their large surface area with high sorption capacity, NPs can be used to reduce excess TEs uptake by plants. The present review summarizes the effects of NPs on plant growth, photosynthesis, mineral nutrients uptake and TEs concentrations. It also highlights the possible mechanisms underlying NPs-mediated reduction of TEs toxicity at the soil and plant interphase. Nanoparticles are effective in immobilization of TEs in soil through alteration of their speciation and improving soil physical, chemical, and biological properties. At the plant level, NPs reduce TEs translocation from roots to shoots by promoting structural alterations, modifying gene expression, and improving antioxidant defense systems. However, the mechanisms underlying NPs-mediated TEs uptake and toxicity reduction vary with NPs type, mode of application, time of NPs exposure, and plant conditions (e.g., species, cultivars, and growth rate). The review emphasizes that NPs may provide new perspectives to resolve the problem of TEs toxicity in crop plants which may also reduce the food security risks. However, the potential of NPs in metal-contaminated soils is only just starting to be realized, and additional studies are required to explore the mechanisms of NPs-mediated TEs immobilization in soil and uptake by plants. Such future knowledge gap has been highlighted and discussed.

Synthesis, characterization and advanced sustainable applications of titanium dioxide nanoparticles: A review.

Nanotechnology is capturing great interest worldwide due to their stirring applications in various fields. Among nanoparticles (NPs), titanium dioxide (TiO2) NPs have been widely used in daily life and can be synthesized through various physical, chemical, and green methods. Green synthesis is a non-toxic, cost-effective, and eco-friendly route for the synthesis of NPs. Plenty of work has been reported on the green, chemical, physical and biological synthesis of TiO2 NPs and these NPs can be characterized through high tech. instruments. In the present review, dense data have been presented on the comparative synthesis of TiO2 NPs with different characteristics and their wide range of applications. Among the TiO2 NPs synthesis techniques, the green methods have been proven to be efficient than chemical synthesis methods because of the less use of precursors, time-effectiveness, and energy-efficiency during the green synthesis procedures. Moreover, this review describes the types of plants (shrubs, herbs and trees), microorganisms (bacteria, fungi and algae), biological derivatives (proteins, peptides, and starches) employed for the synthesis of TiO2 NPs. The TiO2 NPs can be effectively used for the treatment of polluted water and positively affected the plant physiology especially under abiotic stresses but the response varied with types, size, shapes, doses, duration of exposure, metal species along with other factors. This review also highlights the regulating features and future standpoints for the measurable enrichment in TiO2 NPs product and perspectives of TiO2 NPs reliable application.

Foliar exposure of zinc oxide nanoparticles improved the growth of wheat (Triticum aestivum L.) and decreased cadmium concentration in grains under simultaneous Cd and water deficient stress.

A pot study was conducted to explore the effectiveness of zinc oxide nanoparticles (ZnO NPs) foliar exposure on growth and development of wheat, zinc (Zn) and cadmium (Cd) uptake in Cd-contaminated soil under various moisture conditions. Four different levels (0, 25, 50, 100 mg/L) of these NPs were foliar-applied at different time periods during the growth of wheat. Two soil moisture regimes (70% and 35% of water holding capacity) were maintained from 6 weeks of germination till plant harvesting. The results revealed that the growth of wheat increased with ZnO NPs treatments. The best results were found in 100 mg/L ZnO NPs under normal moisture level. The lowest Cd and highest Zn concentrations were also examined when 100 mg/L NPs were applied without water deficit stress. In grain, Cd concentrations decreased by 26%, 81% and 87% in normal moisture while in water deficit conditions, the Cd concentrations decreased by 35%, 66% and 81% compared to control treatment when ZnO NPs were used at 25, 50 and 100 mg/L. The foliar exposure of ZnO NPs boosted up the leaf chlorophyll contents and also decreased the oxidative stress and enhanced the leaf superoxide dismutase and peroxidase activities than the control. It can be suggested that foliar use of ZnO NPs might be an efficient way for increasing wheat growth and yield with maximum Zn and minimum Cd contents under drought stress while decreasing the chances of NPs movement to other environmental compartment which may be possible in soil applied NPs.

Effect of gibberellic acid on growth, biomass, and antioxidant defense system of wheat (Triticum aestivum L.) under cerium oxide nanoparticle stress.

Recently nanoparticles (NPs) are ubiquitous in the environment because they have unique characteristics which are the reason of their wide use in various fields. The release of NPs into various environmental compartments mainly ends up in the soil through water bodies which is a serious threat to living things especially plants. When present in soil, NPs may cause toxicity in plants which increase significance to minimize NPs stress in plants. Although gibberellic acid (GA) is one of the phytohormones that has the potential to alleviate abiotic/biotic stresses in crops plant, GA-mediated alleviation of cerium oxide (CeO2) NPs in plants is still unknown, despite the large-scale application of CeO2-NPs in various fields. The present study was performed to highlight the ability of foliar-applied GA in reducing CeO2-NPs toxicity in wheat under soil exposure of CeO2-NPs. We observed that CeO2-NPs alone adversely affected the dry weights, chlorophyll contents, and nutrients and caused oxidative stress in plants, thereby reducing plant yield. GA coupled with CeO2-NPs reversed the changes caused by CeO2-NPs alone as indicated by the increase in plant growth, chlorophylls, nutrients, and yield. Furthermore, GA alleviated the oxidative stress in plants by enhancing antioxidant enzyme activities under CeO2-NPs exposure than the NPs alone which further provided the evidence of reduction in oxidative damage in plants by GA. Overall, evaluating the potential of GA in reducing CeO2-NPs toxicity in wheat could provide important information for improving food safety under CeO2-NPs exposure.

Effect of composted organic amendments and zinc oxide nanoparticles on growth and cadmium accumulation by wheat; a life cycle study.

Cadmium (Cd) availability in arable soils is a serious issue while little is known about the role of co-composted organic amendments and zinc oxide nanoparticles (ZnO-NPs) foliar spray on biomass and Cd accumulation in wheat grains. The current study investigated the soil application of organic amendment (composted biochar and farmyard manure) at a level of 0, 1, and 2% w/w and foliar spray of ZnO-NPs (0, 100, and 200 mg/L) on biomass, yield, and Cd in wheat grains cultivated in an aged Cd-contaminated agricultural soil. The results indicated that organic amendment increased the biomass, chlorophyll concentrations, yield, and activities of peroxidase and superoxide dismutase of wheat while decreased the electrolyte leakage and Cd concentrations in different parts of wheat such as shoots, roots, husks, and grains. This effect of organic amendment was further enhanced by the foliar spray of ZnO-NPs in a dose-additive manner. Cadmium concentration in grains was below threshold level (0.2 mg/kg DW) for cereals in combined application of 200 mg/L ZnO-NPs and 1% organic amendment as well as in higher treatment (2%) of organic amendment and NPs. Thus, combined use of organic materials and NPs might be a suitable way of reducing Cd and probably other toxic trace element concentrations in wheat and other cereals.

Simultaneous mitigation of cadmium and drought stress in wheat by soil application of iron nanoparticles.

Excess amount of cadmium (Cd) in arable soils and shortage of good quality water are the major abiotic factors affecting the crop yield which needs immediate solution to feed the increasing population worldwide. Recently, nanoparticles (NPs) are widely used in various industries including agriculture which is due to the unique properties of NPs. Among NPs, iron (Fe) NPs might be used to alleviate the abiotic stresses in crops but limited informations are available in the literature about the role of Fe-NPs in crops under metal stress. The present study was designed to highlight the efficiency of Fe-NPs on Cd accumulation in Cd and drought-stressed wheat. Wheat plants were grown in Cd-contaminated soil after the supply of different levels of Fe-NPs and two water regimes were introduced in the soil in latter growth stages of the plants. Cadmium and drought stress negatively affected the wheat photosynthesis, yield and caused oxidative stress in leaves with excess accumulation of Cd in grains and other plant tissues. The NPs improved the photosynthesis, yield, Fe concentrations and diminished the Cd concentrations in tissues. The NPs alleviated the oxidative stress in leaves and the efficiency depends on the NPs concentrations applied in the soil. The results obtained indicated that Fe-NPs may be employed aiming to get wheat grains with excess Fe and decreased Cd contents. However, field investigations with various sizes, shapes and levels of NPs are needed before final recommendations to the farmers.