Phytoremediation of dinitrophenol from wastewater by atriplex lentiformis: effect of salicylic acid.

Quail bush [Atriplex lentiformis (Torr.) S. Wats] plants were used in removing 2, 4-dinitrophenol (DNP) from wastewater in a hydroponic experiment. The hydroponic system contained three doses of DNP, i.e., 0, 10, and 20 mg L-1. Quail bush plants were sprayed with 0.1 mM salicylic acid (SA) to study its role in resisting DNP toxicity. DNP significantly (p < 0.05) reduced plant growth. Exposure of A. lentiformis plants to 20 mg L-1 of DNP reduced the total chlorophyl and relative water content by 39 and 24%, respectively. SA improved the antioxidant defense in terms of ascorbate peroxidase (APX) and polyphenol oxidase (PPO) activities. SA alleviated DNP toxicity by enhancing the production of osmoprotectants, e.g.,proline, phenols, and carbohydrates. SA enhanced the removal efficiency of DNP and the highest removal efficiency (96%) was recorded in the plants sprayed with SA and grown on 10 mg L-1 of DNP. A. lentiformis is a halophytic plant that has good physiological characteristics to resist 2, 4-dinitrophenol toxicity in wastewaters and is qualified to purify water from these harmful compounds. Exogenous application of 0.1 mM SA increased the defense system in A. lentiformis against 2, 4-dinitrophenol toxicity and enhanced the removal efficiency.

2, 4-dinitrophenol inhibited the synthesis of photosynthetic pigments.Salicylic acid protects the vital bio-compounds in plant cells.Atriplex plants are able to remove (96%) of 2, 4-dinitrophenol from the wastewater.Atriplex plants have a strong antioxidant defense enable them to survive in wastewater.

Impact of sewage water irrigation on Datura innoxia grown in sandy loam soil.

BACKGROUND: A potential solution for recycling and reusing the massively produced sewage water (SW) is to irrigate certain plants instead of highly cost recycling treatment. Although the extensive and irrational application of SW may cause environmental pollution thus, continual monitoring of the redox status of the receiver plant and the feedback on its growth under application becomes an emergent instance. The impact of SW, along with well water (WW) irrigation of medicinal plant, Datura innoxia, was monitored by some physio-biochemical indices. RESULTS: The SW application amplified the growth, yield, minerals uptake, and quality of D. innoxia plants compared to the WW irrigated plants. The total chlorophyll, carotenoid, non-enzymatic antioxidants, viz. anthocyanin, flavonoids, phenolic compounds, and total alkaloids increased by 85, 38, 81, 50, 19, and 37%, respectively, above WW irrigated plants. The experiment terminated in enhanced leaf content of N, P, and K by 43, 118, and 48%, respectively. Moreover, stimulation of carbon and nitrogen metabolites in terms of proteins, soluble sugars, nitrate reductase (NR) activity, and nitric oxide (NO) content showed significant earliness in flowering time. The SW application improved not only Datura plants' quality but also soil quality. After four weeks of irrigation, the WW irrigated plants encountered nutrient deficiency-induced stress evidenced by the high level of proline, H2O2, and MDA as well as high enzyme capabilities. Application of SW for irrigation of D. innoxia plant showed the improvement of secondary metabolites regulating enzyme phenylalanine ammonia-lyase (PAL), restored proline content, and cell redox status reflecting high optimal condition for efficient cellular metabolism and performance along the experiment duration. CONCLUSIONS: These evidences approved the benefits of practicing SW to improve the yield and quality of D. innoxia and the feasibility of generalization on multipurpose plants grown in poor soil.

Effect of phosphorus-loaded biochar and nitrogen-fertilization on release kinetic of toxic heavy metals and tomato growth.

In this study, we investigate the effect of nitrogen fertilizer application rates with and without phosphorus-loaded biochar (BCP) on the productivity of tomato (Solanum lycopersicum cv GS) planted on a contaminated soil based on pot and incubation experiments. The release kinetic of toxic metals as affected by BCP was also investigated. BCP at rate of 2% (w/w) and nitrogen levels (250 and 500 mg N kg-1) were added to sandy loam soil polluted with Cd, Pb, Zn, and Cu. The experiment consisted of five treatments including: Control (C), nitrogen a rate of 250 (N250), or 500 mg kg (N500), BCP + N250, and BCP + N500. Maximum tomato growth was achieved in the soil that was treated with BCP + N500, followed by BCP + N250, while lowest one was observed in the control. Tomato yield as affected by the BCP and N-fertilization was in the descending order: BCP + N500 > BCP + N250 > N500 = N250 > C. The addition of N250, N500, BCP + N250, and BCP + N500 increased the fruit yield by 24, 31, 35, 58% in comparison with the control. Levels of Zn, Cu, and Pb in tomato fruit was in the descending order: N500> N250 > C > BCP + N500 > BCP + N250. The combined application of BCP and N-fertilization augmented the availability and uptake of essential nutrients and effectively reduced those of toxic ones. The addition of BCP + N250 decreased Zn, Cu, Cd, and Pb content in fruit of tomato by 16, 10, 54, 54, and 58%, respectively, compared to the control soil, while these decreases were 13, 16, 60, 60, and 72% in the case of BCP + N500. BCP succeeded significantly in reducing the release of toxic chemicals, which ultimately may restrict the transfer of toxic chemical to the food chain solution. Novelty statement Tomato grown on metal-contaminated soils contains high levels of toxic metals. Phosphorus-loaded biochar (BCP) reduced the negative effects of high inorganic-N rates by reducing the release of toxic metals to the soil solution. BCP enhanced the soil quality indicators and increased the soil microbe's activity.

Recycling of sugar crop disposal to boost the adaptation of canola (Brassica napus L.) to abiotic stress through different climate zones.

We need to produce higher foods even under declining natural resources to feed the projected population of 9 billion by 2050 and to sustain food security and nutrition. Abiotic stress has adversely affected canola crop and oil quality especially in sandy soils. To combat this stress, adaptation at the farm level using new and cost-effective amendments are required. Field trials were conducted in two different climatic zones to determine the efficacy of cane molasses, bagasse ash, sugar beet factory lime, and their compost mixtures to improve soil quality and heat stress-adapting canola. The results showed a significant improvement in bulk density, hydraulic conductivity, organic matter content, and available macronutrients of sandy soil and subsequent canola growth, yield, quality and water productivity due to the application of the tested soil amendments, particularly those mixed with compost. Despite the estimated reduction of yield by 18.5% due to heat stress, application of sugar beet lime and compost mixture not only compensated for this reduction but also increased the seed yield by 27.0%. These findings highlight the value of recycling compost-based sugar crop disposal as a cost-effective technology to boost crop tolerance to abiotic stress, ensuring sustainable agriculture and food security in arid environments.

Impact of compost on metals phytostabilization potential of two halophytes species.

Phytostabilization of heavy metals in contaminated soils should be subject to two conditions, the first is the choice plant must be able to stabilize heavy metals in soil, the second is the plant material which produced from the phytostabilization process must be safe and useful to avoid overload on environmental system. A field experiment was conducted out to evaluate the phytostabilization potential of two halophytes species (Atriplex lentiformis and Atriplex undulata). Compost at rates of 0, 15 and 30 ton ha(-1) was used to examine its role in plant growth and heavy metals uptake. The high rate of compost (30 ton ha(-1)) decreased zinc (Zn) concentrations in the leaves of A. lentiformis and A. undulata by 15.8 and 13.0%, while lead (Pb) in the leaves decreased by 37.6 and 35.2% respectively. Despite the extremely high total heavy metals concentrations in the studied soil, plants of Atriplex were able to grow and maintain shoots metals content below the toxic level and the produced plant materials had a high nutritive value compared to the conventional forage crops. Phosphorus (P) and chloride (Cl) in the roots of Atriplex plants play important function in heavy metals phytostabilization mechanism by the two halophytes plants.

In Vitro Propagation Technology for the Endangered Aquatic Species Nymphoides coronata.

Nymphoides coronata is an endangered aquatic plant species with significant medicinal and ecological importance. To preserve N. coronata from going extinct, we need to provide seedlings and efficient multiplication techniques so that it can be extensively studied. This study aimed to identify the most suitable sterilization treatment, growth medium, and substrate for the cultivation and propagation of N. coronata. Ethanol sterilization, fungicide treatment, and sterile water washing were the most important sterilization steps. A combination of 6-benzylaminopurine (6-BA) and indoleacetic acid (IAA) was the most suitable medium for bud induction and shoot proliferation. The use of α-naphthaleneacetic acid (NAA) increased the rooting rate and rooting time compared to indole-3-butyric acid (IBA). Increasing the concentration of NAA from 0.5 to 1.0 mg/L increased the rooting rate from 78 to 100% and reduced the rooting time from 7 to 5 days. The survival rate of N. coronata seedlings was 100% in a mixture of red soil and sand (1:1, w/w). As a result, the procedure mentioned above could potentially be used to safely propagate this rare species on a large scale. These findings provide valuable insights into the optimal conditions for the successful cultivation and propagation of N. coronata, which can contribute to the conservation and sustainable use of this important rare plant species.

Effect of selenium form and dose on camelthorn (Alhagi maurorum Medik) grown on a metal-contaminated soil.

Selenium (Se) enhances the resistance of plants exposed to metal stress and can be used to lessen the impacts of toxic elements and to enhance the effectiveness of the plants used to clean up polluted sites. There is no information available about the optimum dose and form of Se to stimulate the camelthorn (Alhagi maurorum Medik) plant, which is one of the plants used in the phytostabilization of toxic elements. The impacts of selenate (Se-VI) and selenite (Se-IV) on the phytoremediation of toxic metals from loamy soils by camelthorn were investigated in a pot experiment. Se-VI and Se-IV were added to the soil at doses of 0, 5, and 10 mg Se kg-1 soil, and each treatment was repeated five times. Se-VI and Se-IV, significantly increased plant growth and nutrient uptake. The addition of Se, either from Se-VI or Se-IV, significantly increased the superoxide dismutase (SOD) and peroxidase (POD) enzymes, and the non-enzymatic antioxidant compounds, i.e., proline and phenols, compared to the control. The addition of Se strengthened the defense against metal stress, and Se-VI outperformed Se-IV in boosting camelthorn's resistance to hazardous metal contamination. Selenium increased the accumulation of metal in the root of camelthorn and reduced root-shoot transfer. The best technique to boost camelthorn plants' capacity to clean up metal-contaminated soils is to supplement them with selenium in the form of selenate at a concentration of 10 mg Se kg-1 soil.

Role of calcium nutrition in plant Physiology: Advances in research and insights into acidic soil conditions - A comprehensive review.

Plant mineral nutrition has immense significance for crop productivity and human well-being. Soil acidity plays a major role in determining the nutrient availability that influences plant growth. The importance of calcium (Ca) in biological processes, such as signaling, metabolism, and cell growth, underlines its critical role in plant growth and development. This review focuses on soil acidification, a gradual process resulting from cation leaching, fertilizer utilization, and drainage issues. Soil acidification significantly hampers global crop production by modifying nutrient accessibility. In acidic soils, essential nutrients, such as nitrogen (N), phosphorus (P), potassium (K), magnesium (Mg), and Ca become less accessible, establishing a correlation between soil pH and plant nutrition. Cutting-edge Ca nutrition technologies, including nanotechnology, genetic engineering, and genome sequencing, offer the potential to deliver Ca and reduce the reliance on conventional soluble fertilizers. These fertilizers not only contribute to environmental contamination but also impose economic burdens on farmers. Nanotechnology can enhance nutrient uptake, and Ca nanoparticles improve nutrient absorption and release. Genetic engineering enables the cultivation of acid-tolerant crop varieties by manipulating Ca-related genes. High-throughput technologies such as next-generation sequencing and microarrays aid in identifying the microbial structures, functions, and biosynthetic pathways involved in managing plant nutritional stress. The ultimate goal is to shed light on the importance of Ca, problems associated with soil acidity, and potential of emerging technologies to enhance crop production while minimizing the environmental impact and economic burden on farmers.

Cd uptake and translocation by camelthorn (Alhagi maurorum Medik): a promising approach for phytoremediation of Cd-contaminated soils.

Camelthorn (Alhagi maurorum Medik) is a desert plant that can withstand a variety of abiotic challenges, including water stress and harsh weather, making it potentially useful for cleaning cadmium (Cd) from contaminated soils. The current study aims to determine the degree of plant tolerance to Cd toxicity and the possibility of using it in the phytoremediation of Cd-contaminated soils. Camelthorn plants were cultivated in soil polluted with Cd at doses of 0, 25, 50, 100, and 200 mg kg-1. The growth, nutrient uptake, Cd concentrations, and some biochemical compounds were determined to study the response of camelthorn plants to Cd stress. Exposure of camelthorn plants to 200 mg kg-1 of Cd inhabited the synthesis of leaf-chlorophyll by 49% compared to the control and reduced the concentrations of nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), iron (Fe), and zinc (Zn) by 43, 36, 43, 50, 67, and 36%, respectively. Camelthorn plants can tolerate up to 11 mg kg-1 of available soil Cd, 65 mg kg-1 in the root, and 22 mg kg-1 in the shoot before experiencing Cd toxicity. Camelthorn plants increased the levels of carbohydrates, total phenols, and proline compounds that were used in the scavenging of reactive oxygen species (ROS). Moreover, the plants increased the activity of antioxidant enzymes, i.e., superoxide dismutase (SOD) and peroxidase (POD), to mitigate the oxidative stress caused by Cd toxicity. The root-shoot transfer (TF) of Cd varied between 0.27 to 0.48, while the bioaccumulation factor (BAF) varied between 1.2 and 2.32. Camelthorn plants have a BAF value higher than 1 and a TF value lower than 1. Camelthorn plants accumulate Cd in the roots with low root-shoot transfer and are suitable for phytostabilization technology. Camelthorn plants have a potent antioxidant defense against the toxicity of Cd, and this finding is a good tool in the remediation of Cd-contaminated soil.

Calcium-Rich Biochar Stimulates Salt Resistance in Pearl Millet (Pennisetum glaucum L.) Plants by Improving Soil Quality and Enhancing the Antioxidant Defense.

Shrimp waste is rich in organic compounds and essential plant nutrients, e.g., calcium (Ca), and converting these wastes to organic fertilizer is important for environmental preservation and to achieve sustainable agricultural management. In the current study, Ca-rich biochar was prepared from shrimp wastes (SWB) by pyrolysis at 300 °C. We hypothesized that the Ca-rich biochar will help in solving the problem of plant growth in saline soil by reducing sodium (Na) uptake and mitigating oxidative stress. The current study aimed to investigate the effect of SWB on the quality of saline sandy soil and the mechanism of salt resistance in pearl millet (Pennisetum glaucum L.). Pearl millet plants were planted in saline sandy soil (10 dS m-1) in wooden boxes (1.3 × 0.8 m size and 0.4 m height), and 5 doses (0, 1.0, 1.5, 2.0, and 2.5% (w/w)) of SWB were added. SWB application increased the soil quality and nutrient uptake by pearl millet plants. The highest rate of SWB increased the soil microbial biomass carbon and the activity of dehydrogenase enzyme by 43 and 47% compared to the control soil. SWB application reduced the uptake of sodium (Na+) and chloride (Cl-) and increased the K/Na ratio in the leaf tissues. SWB addition significantly increased the activity of antioxidant enzymes, e.g., ascorbate peroxidase (APX), polyphenol oxidase (PPO), and pyrogallol peroxidases (PPX). The application of 2.5% SWB to the saline soil increased the soluble carbohydrates and proline in plant leaves by 75 and 60%, respectively, and reduced the malondialdehyde (MDA) by 32% compared to the control. SWB enhanced the antioxidant defense and mitigated oxidative stress by improving the synthesis of osmoprotectants, e.g., soluble carbohydrates and proline. Sandy saline soils in arid and semiarid areas suffer greatly from low organic matter contents, which reduces the soil quality and increases the risk of salt during plant growth. The high organic matter and calcium content (30%) in the shrimp waste-derived biochar improved the quality of the saline sandy soil, reduced the uptake of toxic salts, and increased the quality of the forage material. The addition of recycled shrimp waste to saline low-fertility soils improves soil productivity and is safe for soil health.

Induction of resilience strategies against biochemical deteriorations prompted by severe cadmium stress in sunflower plant when Trichoderma and bacterial inoculation were used as biofertilizers.

Background: Cadmium (Cd) is a highly toxic heavy metal. Its emission is suspected to be further increased due to the dramatic application of ash to agricultural soils and newly reclaimed ones. Thereby, Cd stress encountered by plants will exacerbate. Acute and chronic exposure to Cd can upset plant growth and development and ultimately causes plant death. Microorganisms as agriculturally important biofertilizers have constantly been arising as eco-friendly practices owing to their ability to built-in durability and adaptability mechanisms of plants. However, applying microbes as a biofertilizer agent necessitates the elucidation of the different mechanisms of microbe protection and stabilization of plants against toxic elements in the soil. A greenhouse experiment was performed using Trichoderma harzianum and plant growth-promoting (PGP) bacteria (Azotobacter chroococcum and Bacillus subtilis) individually and integrally to differentiate their potentiality in underpinning various resilience mechanisms versus various Cd levels (0, 50, 100, and 150 mg/kg of soil). Microorganisms were analyzed for Cd tolerance and biosorption capacity, indoleacetic acid production, and phosphate and potassium solubilization in vitro. Plant growth parameters, water relations, physiological and biochemical analysis, stress markers and membrane damage traits, and nutritional composition were estimated. Results: Unequivocal inversion from a state of downregulation to upregulation was distinct under microbial inoculations. Inoculating soil with T. harzianum and PGPB markedly enhanced the plant parameters under Cd stress (150 mg/kg) compared with control plants by 4.9% and 13.9%, 5.6% and 11.1%, 55.6% and 5.7%, and 9.1% and 4.6% for plant fresh weight, dry weight, net assimilation rate, and transpiration rate, respectively; by 2.3% and 34.9%, 26.3% and 69.0%, 26.3% and 232.4%, 135.3% and 446.2%, 500% and 95.6%, and 60% and 300% for some metabolites such as starch, amino acids, phenolics, flavonoids, anthocyanin, and proline, respectively; by 134.0% and 604.6% for antioxidants including reduced glutathione; and by 64.8% and 91.2%, 21.9% and 72.7%, and 76.7% and 166.7% for enzymes activity including ascorbate peroxidase, glutathione peroxidase, and phenylalanine ammonia-lyase, respectively. Whereas a hampering effect mediated by PGP bacterial inoculation was registered on levels of superoxide anion, hydroxyl radical, electrolyte leakage, and polyphenol oxidase activity, with a decrease of 0.53%, 14.12%, 2.70%, and 5.70%, respectively, under a highest Cd level (150 mg/kg) compared with control plants. The available soil and plant Cd concentrations were decreased by 11.5% and 47.5%, and 3.8% and 45.0% with T. harzianum and PGP bacterial inoculation, respectively, compared with non-inoculated Cd-stressed plants. Whereas, non-significant alternation in antioxidant capacity of sunflower mediated by T. harzianum action even with elevated soil Cd concentrations indicates stable oxidative status. The uptake of nutrients, viz., K, Ca, Mg, Fe, nitrate, and phosphorus, was interestingly increased (34.0, 4.4, 3.3, 9.2, 30.0, and 1.0 mg/g dry weight, respectively) owing to the synergic inoculation in the presence of 150 mg of Cd/kg. Conclusions: However, strategies of microbe-induced resilience are largely exclusive and divergent. Biofertilizing potential of T. harzianum showed that, owing to its Cd biosorption capability, a resilience strategy was induced via reducing Cd bioavailability to be in the range that turned its effect from toxicity to essentiality posing well-known low-dose stimulation phenomena (hormetic effect), whereas using Azotobacter chroococcum and Bacillus subtilis, owing to their PGP traits, manifested a resilience strategy by neutralizing the potential side effects of Cd toxicity. The synergistic use of fungi and bacteria proved the highest efficiency in imparting sunflower adaptability under Cd stress.

Improving quality of metal-contaminated soils by some halophyte and non-halophyte forage plants.

Toxic elements cause degradation in agricultural land quality. Phytoremediation of polluted sites is the safest technique to sustain ecosystem. Field trial was established to examine the performance of two Atriplex species (A. numularia and A. amnicola) and two traditional forage plants (pearl millet and cowpea) cultivated on polluted sandy soil and clean one. The studied contaminated soil was irrigated with untreated sewage wastewater for more than 60 years and contained Zn, Cu, Pb and Cd levels excessed the permissible limits. The growth of Atriplex plants was not affected by the soil pollution, while the traditional forage plants lost 40-50% of their biomass. The roots biomass of Atriplex plants was higher by 54% than those of cowpea and pearl millet plants. The crude protein (CP) and chlorophyll in the tested species were reduced as a result of soil pollution, but the reduction was higher in pearl millet and cowpea than Atriplex plants. CP in Atriplex plants that were grown in the contaminated soil was reduced by 10%, while in the case of pearl millet and cowpea; the reduction was more than 20%. Atriplex plants were more effective in reducing the metal bioavailability than pearl millet and cowpea. Atriplex plants were able to protect the photosynthesis process in the presence of toxic elements; moreover, they produced some substances that increasing the resistance of toxic metal stress such as proline. The cultivation of metal-contaminated soil with Atriplex plants enhanced the soil quality and increased the aggregation and porosity of soil; besides, it reduced the soil salinity and concentration of toxic elements. Cultivation of halophyte and traditional fodder plants in contaminated lands is a good strategic management of the ecosystem, and the resulting plant may be used to feed animals due to their low content of pollutants or be recycled to soil organic amendments.

Induction of Catharanthus roseus Secondary Metabolites When Calotropis procera Was Used as Bio-Stimulant.

Available information associated with Calotropis procera posted its phytotoxic effect as bio-herbicide scarce works studied its stimulatory/nutritive effect. A pot experiment was performed to assess the validity of using Calotropis procera (C. procera) leaves extract as a bio-stimulant for the growth and quality of a medicinal plant Catharanthus roseus (C. roseus) evaluated by some physio-biochemical indices. Different types of C. procera leaves extracts (CLEs) (methanolic, cold water and autoclaved water extracts) were delivered by two different modes of application. The results revealed that application of CLEs as irrigation or foliar spraying caused a stimulation effect on C. roseus plant. Root and shoot length, dry and fresh weight were significantly improved due to CLEs applications. C. roseus bioactive molecules such as anthocyanins, phenolics, flavonoids, alkaloids, ascorbic acid, reduced glutathione and α-tocopherol were abundance increased significantly with CLEs applications. Reactive oxygen species (ROS) decreased explaining the involvement of CLEs in induction of antioxidant enzymes catalase, ascorbate peroxidase, polyphenol oxidase, guaiacol peroxidase and glutathione-S-transferase for modifying cell oxidative status witnessed by lower lipid peroxidation that kept below the untreated plants' baseline reflected the improvement of growth and quality rather than phytotoxic effect. The promotion of wholesome-promoting secondary metabolites by CLEs was closely correlated to elevated phenylalanineammonialyase activity. The comparable efficient effect induced by all treatments might be judged by the relation between C. procera phytochemicals and C. roseus metabolism (donor-receiver relation). It is concluded that application of CLEs can be a promising approach for improving the yield and quality of plants despite using polluting fertilizers. The current investigation may provide a matrix for coming studies to seek illustration of numerous plants' response to C. procera extracts.

Biochar and compost enhance soil quality and growth of roselle (Hibiscus sabdariffa L.) under saline conditions.

Soil amendments may increase the slate tolerance of plants consequently; it may increase the opportunity of using saline water in agricultural production. In the present pot trial, the effects of biochar (BIC) and compost (COM) on roselle (Hibiscus sabdariffa L.) irrigated with saline water (EC = 7.50 dS m-1) was studied. Roselle plants were amended with biochar (BIC1 and BIC2) or compost (COM1 and COM2) at rates of 1 and 2% (w/w), as well as by a mixture of the two amendments (BIC1+). The experiment included a control soil without any amendments. Biochar and compost significantly enhanced the soil quality and nutrients availability under saline irrigation. Compost and biochar improved the degree of soil aggregation, total soil porosity and soil microbial biomass. BIC1 + COM1 increased the soil microbial biomass carbon and nitrogen over the individual application of each amendments and control soil. BIC1 + COM1 increased the activity of dehydrogenase and phosphatase enzymes. Growth of roselle plants including: plant height, shoot fresh and dry weight, and chlorophyll were significantly responded to the added amendments. The maximum sepal's yield was achieved from the combined application of compost and biochar. All the investigated treatments caused remarkable increases in the total flavonol and anthocyanin. BIC1 + COM1 increased the total anthocyanin and flavonol by 29 and 17% above the control. Despite the notable improvement in soil and roselle quality as a result of the single addition of compost or biochar, there is a clear superiority due to mixing the two amendments. It can be concluded that mixing of biochar and compost is recommended for roselle plants irrigated with saline water.

Mechanisms of Chitosan Nanoparticles in the Regulation of Cold Stress Resistance in Banana Plants.

Exposure of banana plants, one of the most important tropical and subtropical plants, to low temperatures causes a severe drop in productivity, as they are sensitive to cold and do not have a strong defense system against chilling. Therefore, this study aimed to improve the growth and resistance to cold stress of banana plants using foliar treatments of chitosan nanoparticles (CH-NPs). CH-NPs produced by nanotechnology have been used to enhance tolerance and plant growth under different abiotic stresses, e.g., salinity and drought; however, there is little information available about their effects on banana plants under cold stress. In this study, banana plants were sprayed with four concentrations of CH-NPs-i.e., 0, 100, 200, and 400 mg L-1 of deionized water-and a group that had not been cold stressed or undergone CH-NP treatment was used as control. Banana plants (Musa acuminata var. Baxi) were grown in a growth chamber and exposed to cold stress (5 °C for 72 h). Foliar application of CH-NPs caused significant increases (p < 0.05) in most of the growth parameters and in the nutrient content of the banana plants. Spraying banana plants with CH-NPs (400 mg L-1) increased the fresh and dry weights by 14 and 41%, respectively, compared to the control. A positive correlation was found between the foliar application of CH-NPs, on the one hand, and photosynthesis pigments and antioxidant enzyme activities on the other. Spraying banana plants with CH-NPs decreased malondialdehyde (MDA) and reactive oxygen species (ROS), i.e., hydrogen peroxide (H2O2), hydroxyl radicals (•OH), and superoxide anions (O2•-). CH-NPs (400 mg L-1) decreased MDA, H2O2, •OH, and O2•- by 33, 33, 40, and 48%, respectively, compared to the unsprayed plants. We hypothesize that CH-NPs increase the efficiency of banana plants in the face of cold stress by reducing the accumulation of reactive oxygen species and, in consequence, the degree of oxidative stress. The accumulation of osmoprotectants (soluble carbohydrates, proline, and amino acids) contributed to enhancing the cold stress tolerance in the banana plants. Foliar application of CH-NPs can be used as a sustainable and economically feasible approach to achieving cold stress tolerance.

The Exogenous Application of Micro-Nutrient Elements and Amino Acids Improved the Yield, Nutritional Status and Quality of Mango in Arid Regions.

The mango is one of the most valuable and appealing tropical fruits due to its color, aroma, tasteful remarkable flavor, and nutritive value; however, improving the yield and quality of mango is an urgent goal in order to combat global population growth. The application of amino acids and a micronutrient mixture might improve the yield and quality features but further research is still required in arid regions. To study the combined effect of a micronutrient mixture (MM) and amino acids (AA) at different rates, twenty-seven Fagri Kalan mango trees (15 years old) were carefully selected. The foliar application effect of MM and AA on vegetative growth, total chlorophyll, leaf chemical constituents, productivity, and the fruit quality of mango trees (cv. Fagri Kalan) was investigated. The findings revealed that the investigated growth measurements and leaf chemical contents, as well as the fruiting aspects and the fruit quality improved significantly due to the application of MM and AA. A higher application rate of the micronutrient mixture (2 g L-1) in combination with the highest amino acid concentration (2 mg L-1) was the most effective combination that increased the yield, total soluble solids (TSS), total sugars (TS), and total carbohydrates by 28.0%, 3.0%, 5.8% and 15.0%, respectively, relative to untreated plants. The relationship between such characteristics revealed a strong positive correlation (0.80-0.95), confirming the importance of these materials in increasing the yield and quality of mangoes. Thus, using doses of MM and AA as a foliar spray four times during each growing season is recommended under similar environmental conditions and horticulture practices used in the current experiment.

Effect of Manure and Compost on the Phytostabilization Potential of Heavy Metals by the Halophytic Plant Wavy-Leaved Saltbush.

This study aimed to use organic fertilizers, e.g., compost and manures, and a halophytic plant [wavy-leaved saltbush (Atriplex undulata)] to remediate an agricultural soil polluted with toxic elements. Compost or manure (1% w/w) was added to a polluted soil in a pot trial. The application of the organic fertilizer, whether compost or manure, led to a significant improvement in the growth of the tested plant. From the physiological point of view, the application of organic fertilizers to polluted soil significantly increased the content of chlorophyll, carotenoid, and proline and, furthermore, led to a clear decrease in malondialdehyde (MDA) in the plant leaves. The highest significant values of organic carbon in the polluted soil (SOC) and cation exchange capacity (CEC) were found for the soil amended by compost and planted with wavy-leaved saltbush. Manure significantly reduced the soil pH to 7.52. Compost significantly decreased Zn, Cu, Cd, and Pb availability by 19, 8, 12, and 13%, respectively, compared to the control. On the other hand, manure increased Zn, Cu, Cd, and Pb availability by 8, 15, 18, and 14%, respectively. Compost and manure reduced the bioconcentration factor (BCF) and translocation factor (TF) of Cd and Pb. Compost was more effective in increasing the phytostabilization of toxic metals by wavy-leaved saltbush plants compared to manure. The results of the current study confirm that the application of non-decomposed organic fertilizers to polluted soils increases the risk of pollution of the ecosystem with toxic elements. The cultivation of contaminated soils with halophytic plants with the addition of aged organic materials, e. g., compost, is an effective strategy to reduce the spreading of toxic metals in the ecosystem, thus mitigating their introduction into the food chain.

Growth and biochemical changes in quail bush (Atriplex lentiformis (Torr.) S.Wats) under Cd stress.

Halophytes have several advantages to be more effective in metal phytoextraction. Little is known about the Cd-phytoextraction potential of Atriplex lentiformis under different levels of Cd. Seven levels of Cd (0, 40, 80, 120, 160, 200, and 240 mg per kg of soil) were added to A. lentiformis plants grown on pots filled with 5 kg of sandy loam soil. A. lentiformis plants achieve different defense mechanisms to meet the high concentration of Cd in the soil and plant. These mechanisms include reducing the number and area of leaves, minimizing chlorophyll synthesis, and enhancing synthesizing of oxalic acid, phenols, and proline. The critical point of Cd was 9.35 and 183 mg kg-1 for available soil Cd and leaves concentrations, respectively. The maximum level of Cd displayed a 66% decrease in the chlorophyll content of the leaves. On the other hand, the oxalic acid, phenols, and proline in the leaves were increased significantly by 129, 100, and 200% when Cd increased from 0 to 240 mg. The tested plant removed 3.6% of the total soil Cd under the low Cd concentration (40 mg) but under the high level of Cd (240 mg), it only removed a negligible amount of soil Cd (0.74%). The current study confirmed that A. lentiformis plants lost the ability to cleanup Cd from contaminated soil under the high levels of contamination due to the high reduction in the production of dry matter.

Effect of sugarcane vinasse and EDTA on cadmium phytoextraction by two saltbush plants.

Although the use of saltbush plants in metal phytoremediation is well known, there is little information about the impact of sugarcane vinasse (SCV) and EDTA on metal uptake. Heavily cadmium-polluted soil (38 mg kg(-1) Cd) was used in pot and incubation experiments to investigate the Cd phytoextraction potential of wavy saltbush (Atriplex undulata) and quail saltbush (Atriplex lentiformis). EDTA at rates of 3, 6, and 10 mM kg(-1) soil and SCV at rates of 7, 15, and 30 mL kg(-1) soil were added to the polluted soil. The application of EDTA significantly (P = 0.002) reduced the growth of saltbush plants; on the other hand, SCV improved the growth. Both EDTA and SCV increased the availability and root-to-shoot transfer of Cd. The plants of A. lentiformis grown on the soil amended with the highest rate of SCV were able to remove 20.4 % of the total soil Cd during a period of 9 months. Based on the obtained results, it may be concluded that A. lentiformis and sugarcane vinasse could be more effective in the phytoextraction of Cd from the polluted soils.