Integrative approaches to improve litchi (Litchi chinensis Sonn.) plant health using bio-transformations and entomopathogenic fungi.

Bio-transformations refer to the chemical modifications made by an organism on a chemical compound that often involves the interaction of plants with microbes to alter the chemical composition of soil or plant. Integrating bio-transformations and entomopathogenic fungi into litchi cultivation can enhance symbiotic relationships, microbial enzymatic activity in rhizosphere, disease suppression and promote overall plant health. The integration of biological formulations and entomopathogenic fungi can significantly influence growth, nutrient dynamics, physiology, and rhizosphere microbiome of air-layered litchi (Litchi chinensis Sonn.) saplings. Biological modifications included, K-mobilizers, AM fungi, Pseudomonas florescence and Azotobacter chroococcum along with Metarhizium, entomopathogenic fungi have been used. The treatments included, T1-Litchi orchard soil + sand (1:1); T2-Sand + AM fungi + Azotobacter chroococcum (1:2:1); T3-Sand + Pseudomonas florecence + K-mobilizer (1:1:1); T4- AM fungi + K-mobilizers (1:1); T5, P. Florecence + A. chroococcum + K-mobilizer (1:1:1); T6-Sand + P. florecence (1:2) and T7-Uninoculated control for field performance. Treatments T4-T6 were further uniformly amended with drenching of Metarrhizium in rhizosphere. T2 application significantly increased resident microbe survival, total chlorophyll content and root soil ratio in seedlings. A. chroococcum, Pseudomonas, K-mobilizers and AM fungi increased in microbial biomass of 2.59, 3.39, 2.42 and 2.77 times, respectively. Acidic phosphatases, dehydrogenases and alkaline phosphatases were increased in rhizosphere. Leaf nutrients reflected through DOP were considerably altered by T2 treatment. Based on Eigen value, PCA-induced changes at biological modifications showed maximum total variance. The study inferred that the bio-transformations through microbial inoculants and entomopathogenic fungi could be an encouraging strategy to enhance the growth of plants, health and productivity. Such practices align well with the goals of sustainable agriculture through biological means by reducing dependency on chemical inputs. By delving into these aspects, the research gaps including microbial processes, competitive and symbiotic relationships, resistance in microbes and how complex interactions among bio-transformations, entomopathogenic fungi and microbes can significantly impact the health and productivity of litchi. Understanding and harnessing these interactions can lead to more effective and sustainable farming practices.

Design and Development of Sustainable Cu2 (II)- and Mn2 (III)-Embedded Bifunctional Electrocatalysts: Enhanced Hydrogen and Oxygen Generation.

Nowadays, environmentally friendly, low-cost-effective, and sustainable electrocatalysts used widely for hydrogen and oxygen evolution reactions have come into the limelight as a new research topic for scientists. This study highlights the preparation of two unique and symmetrical dinuclear Cu (II) and Mn (III) bifunctional catalysts by a facile simple slow evaporation and diffusion route. [C32H24Cu2F4N4O4] (1) and [C32H24Mn2F4N4O4] (2) both have monoclinic (C2/c (15)) crystal systems, with oxidation states +2 and +3, respectively. Prominent SPR peaks at 372 and 412 nm indicate an M-L charge transfer transition in both complexes. The synthesized electrocatalysts display exceptional catalytic activity for the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). Complex 1 exhibits enhanced hydrogen generation in 0.5 M H2SO4 with a small overpotential of 216 mV at -10 mA cm-2 along with a significantly lower Tafel value of 97 mV/dec compared to Complex 2. Moreover, Complex 1 is highly active for the OER in 1 M KOH with a small Tafel slope of 103 mV/dec and a low overpotential of 340 mV to acquire 10 mA cm-2 current density, compared to Complex 2. Complex 1 and Complex 2 remain stable up to 20 h in acidic electrolyte and up to 36 h and 20 h in the basic electrolyte, respectively.

Comprehensive Assessment of Herbicide Toxicity on Navicula sp. Algae: Effects on Growth, Chlorophyll Content, Antioxidant System, and Lipid Metabolism.

This study investigated the effects of herbicide exposure on Navicula sp. (MASCC-0035) algae, focusing on growth density, chlorophyll content, antioxidant system, and lipid metabolism. Navicula cultures were exposed to different concentrations of atrazine (ATZ), glyphosate (Gly), and acetochlor (ACT) for 96 h. Results showed a significant decrease in cell numbers, with higher herbicide concentrations having the most noticeable impacts. For instance, Gly-G2 had reduced cell populations by 21.00% at 96 h. Chlorophyll content varied, with Gly having a greater impact on chlorophyll a compared to ATZ and ACT. Herbicide exposure also affected the antioxidant system, altering levels of soluble sugar, soluble protein, and reactive oxygen species (ROS). Higher herbicide rates increased soluble sugar content (e.g., ATZ, Gly, and ACT-G2 had increased by 14.03%, 19.88%, and 19.83%, respectively, at 72 h) but decreased soluble protein content, notably in Gly-G2 by 11.40%, indicating cellular stress. Lipid metabolism analysis revealed complex responses, with changes in free proline, fatty acids, and lipase content, each herbicide exerting distinct effects. These findings highlight the multifaceted impacts of herbicide exposure on Navicula algae, emphasizing the need for further research to understand ecological implications and develop mitigation strategies for aquatic ecosystems.

Targeted therapy using nanocomposite delivery systems in cancer treatment: highlighting miR34a regulation for clinical applications.

The clinical application of microRNAs in modern therapeutics holds great promise to uncover molecular limitations and conquer the unbeatable castle of cancer metastasis. miRNAs play a decisive role that regulating gene expression at the post-transcription level while controlling both the stability and translation capacity of mRNAs. Specifically, miR34a is a master regulator of the tumor suppressor gene, cancer progression, stemness, and drug resistance at the cell level in p53-dependent and independent signaling. With changing, trends in nanotechnology, in particular with the revolution in the field of nanomedicine, nano drug delivery systems have emerged as a prominent strategy in clinical practices coupled with miR34a delivery. Recently, it has been observed that forced miR34a expression in human cancer cell lines and model organisms limits cell proliferation and metastasis by targeting several signaling cascades, with various studies endorsing that miR34a deregulation in cancer cells modulates apoptosis and thus requires targeted nano-delivery systems for cancer treatment. In this sense, the present review aims to provide an overview of the clinical applications of miR34a regulation in targeted therapy of cancer.

Simultaneous immobilization of lead and arsenic and improved phosphorus availability in contaminated soil using biochar composite modified with hydroxyapatite and oxidation: Findings from a pot experiment.

Multi-metals/metalloids contaminated soil has received extensive attention because of their adverse health effects on the safety of the food chain and environmental health. In order to provide additional insight and aid in mitigating environmental risks, a pot experiment was directed to assess the impacts of biochars derived from rice straw (BC), and modified biochars i-e., hydroxyapatite modified (HAP-BC) and oxidized biochars (Ox-BC) on the redistribution, phytoavailability and bioavailability of phosphorus (P), lead (Pb), and Arsenic (As), as well as their effects on the growth of maize (Zea mays L.) in a Lead (Pb)/Arsenic (As) contaminated soil. The results showed that HAP-BC increased the soil total and available P, compared with raw biochar and control treatment. HAP-BC improved soil properties by elevating soil pH and electric conductivity (EC). The Hedley fractionation scheme revealed that HAP-BC enhanced the labile and moderately labile P species in soil. Both HAP-BC and Ox-BC assisted in the P build-up in plant roots and shoots. The BCR (European Community Bureau of Reference) sequential extraction data for Pb and As in soil showed the pronounced effects of HAP-BC towards the transformation of labile Pb and As forms into more stable species. Compared with control, HAP-BC significantly (P ≤ 0.05) decreased the DTPA-extractable Pb and As by 55% and 28%, respectively, subsequently, resulting in reduced Pb and As plant uptakes. HAP-BC application increased the plant fresh and dry root/shoot biomass by 239%, 72%, 222% and 190%, respectively. The Pb/As immobilization by HAP-BC was mainly driven by precipitation, ion exchange and surface complexation mechanisms in soil. In general, HAP-BC application indicated a great capability to be employed as an effective alternative soil amendment for improving P acquisition in soil, simultaneously immobilizing Pb and As in the soil-plant systems.

A systematic review on the bioremediation of metal contaminated soils using biochar and slag: current status and future outlook.

Heavy metals contaminated soils are posing severe threats to food safety worldwide. Heavy metals absorbed by plant roots from contaminated soils lead to severe plant development issues and a reduction in crop yield and growth. The global population is growing, and the demand for food is increasing. Therefore, it is critical to identify soil remediation strategies that are efficient, economical, and environment friendly. The use of biochar and slag as passivators represents a promising approach among various physicochemical and biological strategies due to their efficiency, cost-effectiveness, and low environmental impact. These passivators employ diverse mechanisms to reduce the bioavailability of metals in contaminated soils, thereby improving crop growth and productivity. Although studies have shown the effectiveness of different passivators, further research is needed globally as this field is still in its early stages. This review sheds light on the innovative utilization of biochar and slag as sustainable strategies for heavy metal remediation, emphasizing their novelty and potential for practical applications. Based on the findings, research gaps have been identified and future research directions proposed to enable the full potential of passivators to be utilized effectively and efficiently under controlled and field conditions.

Phenolic composition of grape pomace and its metabolism.

Grape pomace is the most important residual after wine making, and it is considered to be a very abundant source for the extraction of a wide range of polyphenols. These polyphenols exhibit a variety of bioactivities, such as antioxidant, anti-inflammatory, and anti-cancer. They are also beneficial in alleviating metabolic syndrome and regulating intestinal flora, etc. These health effects are most likely contributed by polyphenol metabolite, which are formed by the grape pomace phenolics after a complex metabolic process in vivo. Therefore, understanding the phenolic composition of grape pomace and its metabolism is the basis for an in-depth study of the biological activity of grape pomace polyphenols. In this paper, we first summarize the composition of phenolics in grape pomace, then review the recent studies on the metabolism of grape pomace phenolics, including changes in phenolics in the gastrointestinal tract, their pharmacokinetics in the systemic circulation, the tissue distribution of phenolic metabolites, and the beneficial effects of metabolites on intestinal health, and finally summarize the effects of human health status and dietary fiber on the metabolism of grape polyphenols. It is expected to provide help for the in-depth research on the metabolism and biological activity of grape pomace polyphenol extracts, and to provide theoretical support for the development and utilization of grape pomace.

A green method for removing chromium (VI) from aqueous systems using novel silicon nanoparticles: Adsorption and interaction mechanisms.

In the present study, we used the horsetail plant (Equisetum arvense) as a green source to synthesize silicon nanoparticles (GS-SiNPs), considering that it could be an effective adsorbent for removing chromium (Cr (VI)) from aqueous solutions. The characterization of GS-SiNPs was performed via Brunauer-Emmett-Teller (BET), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and X-ray photo electron spectroscopy (XPS) techniques. The batch test results of Cr (VI) adsorption on GS-SiNPs showed a high adsorption capacity, reaching 87.9% of the amount added. The pseudo-second order kinetic model was able to comprehensively explain the adsorption kinetics and provided a maximum Cr (VI) adsorption capacity (Qe) of 3.28 mg g-1 (R2 = 90.68), indicating fast initial adsorption by the diffusion process. The Langmuir isotherm model fitted the experimental data, and accurately simulated the adsorption of Cr (VI) on GS-SiNPs (R2 = 97.79). FTIR and XPS spectroscopy gave further confirmation that the main mechanism was ion exchange with Cr and surface complexation through -OH and -COOH. Overall, the results of the research can be of relevance as regards a green and new alternative for the removal of Cr (VI) pollution from affected environments.

Nano-hydroxyapatite modified biochar: Insights into the dynamic adsorption and performance of lead (II) removal from aqueous solution.

Adsorption of lead as Pb(II) using biochar is an environmentally sustainable approach to remediate this kind of pollution affecting wastewater. In this study, rice straw biochar (BC) was modified by combination with nano-hydroxy-apatite (HAP), resulting in a material designated as BC@nHAP, with enhanced adsorption performance. Based on Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) analyses, it was evidenced that, after modification, HAP greatly enhanced surface functional groups (i.e., -COOH and/or -OH) of raw biochar's surface. Batch tests showed that the maximum sorption capacity of BC (63.03 mg g-1) was improved due to the modification, reaching 335.88 mg g-1 in BC@nHAP. Pseudo-second order (PSO) kinetics fitted well the adsorption data (R2 = 0.99), as well as the Langmuir isotherm model (showing an adsorption value of 335.88 mg g-1 for qe). The results of thermodynamic calculations showed that the adsorption was primarily governed by chemisorption process. FTIR spectroscopy and XPS spectrum after adsorption further confirmed that the adsorption mechanisms were ion exchange with Pb2+ and surface complexation by -OH and -COOH. In addition, BC@nHAP revealed a brilliant regeneration capability. The maximum adsorption capacity by BC@nHAP was higher than that of raw biochar or other previously reported adsorbents. Therefore, BC@nHAP could be seen as a new sorbent material with high potential for real-scale heavy metal removal from wastewater, and specifically as a capable candidate new sorbent for Pb(II) removal from wastewater, which has clear implications as regard preservation of environmental quality and public health.

Highly efficient uranium (VI) capture from aqueous solution by means of a hydroxyapatite-biochar nanocomposite: Adsorption behavior and mechanism.

The exploration and rational design of easily separable and highly efficient sorbents with the sufficient capability of retaining radioactive and toxic uranium U(VI) is paramount. In this study, a hydroxyapatite (HAP) biochar nanocomposite (BR/HAP) was successfully fabricated from rice straw biochar (BR), to be used as a new and efficient adsorbent for removing U(VI) from aqueous solution. Both BR and the BR/HAP composite were characterized via Brunauer-Emmett-Teller (BET), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and X-ray photo electron spectroscopy (XPS) techniques. Batch test results showed that BR/HAP exhibited remarkably higher adsorption capacity than the raw BR. A pseudo-second order kinetic model thoroughly explained the adsorption kinetics, providing the maximum U(VI) adsorption capacities (qe) of 110.56 mg g-1 (R2 = 0.98) and 428.25 mg g-1 (R2 = 0.99), for BR and BR/HAP, respectively, which was indicative of the rate-limited sorption via diffusion or surface complexation after rapid initial adsorption steps. The Langmuir isotherm model fitted the experimental data to accurately simulate the adsorption of U(VI) onto BR and BR/HAP (R2 = 0.97 and R2 = 0.99). The thermodynamic results showed negative values for ΔG°, clearly indicating that the reaction was spontaneous, as well as positive values for ΔH° (11.04 kJ mol-1 and 28.86 kJ mol-1, respectively) and ΔS° (88.97 kJ mol-1 K-1, and 183.42 kJ mol-1 K-1), making clear the endothermic nature of U(VI) adsorption onto both sorbents, with an increase in randomness at a molecular level. FTIR spectroscopy and XPS spectrum further confirmed that the primary mechanisms were ion exchange with UO22+ and surface complexion by -OH and -COOH. In addition, BR/HAP showed an excellent reusability, making it a promising candidate as a new sorbent for U(VI) removal from wastewater. In view of that, it would be interesting to perform future research to explore practical implications of this sorbent material regarding protection from environmental and public health issues related to that pollutant.

Adsorption of arsenic (III) from aqueous solution by a novel phosphorus-modified biochar obtained from Taraxacum mongolicum Hand-Mazz: Adsorption behavior and mechanistic analysis.

A novel phosphorus (P) modified biochar (PLBC) was produced by pyrolyzing biomass of the dietic herb Taraxacum mongolicum Hand-Mazz (TMHM) and treating it with monopotassium phosphate (KH2PO4). This phosphorous loaded biochar was then assessed as adsorbent for As(III) removal from contaminated water. In the current research, the adsorbent was characterized before and after P loading by means of SEM-EDX, TEM, FTIR and XRD techniques. It was evidenced that the presence of P on the surface of the biochar (BC) could improve its efficiency to remove As(III) from contaminated environments. Adsorption kinetics were evaluated by performing batch-type experiments at varied times and pH values (5, 7 and 9). The kinetic study revealed that a contact time of 24 h was required to attain equilibrium and the experimental data were best fitted to the pseudo-second-order kinetic model (qe = 17.1 mg g-1). In addition, several batch experiments were conducted with varied arsenic concentrations. During the adsorption tests, the maximum adsorption of As(III) was found at pH 5. The adsorption study further showed that compared to BC, PLBC depicted increased removal of As(III) from contaminated solutions. The adsorption experimental data showed the best fit to the Langmuir isotherm model (with R2 = 0.84), with maximum As(III) adsorption capacity reaching 30.76 mg g-1 for PLBC.

Influence of Aquatic pH on chemical speciation, phytochelation and vacuolar compartmentalization of arsenic in Vallisneria denseserrulata (Makino).

Arsenic (As) pollution of fresh water has become a major concern worldwide. The present study reports the As accumulation potential and detoxification mechanism in a native plant, Vallisneria denseserrulata (Makino), under different aquatic acidity conditions (pH). V. denseserrulata showed maximum growth at pH ∼7.0 and accumulated ∼1700 mg/kg of As. The increase in pH from 3.5 to 7 significantly (p ≤ 0.05) increased As accumulation, thiol and total protein contents while malondialdehyde (MDA) content, soluble sugar content and percentage electrolytic leakage (%EL) of V. denseserrulata were decreased. The reduction of arsenate [As(V)] to arsenite As(III) was observed as a key step (81% reduction) of the As detoxification in V. denseserrulata. Majority of accumulated As was found in vacuoles (56-72%), while >80% of As in vacuoles was in the form of As(III). FT-IR spectra indicated the complexsation of As with carboxyl, amide, thiol, and hydroxyl groups. Our findings showed the presence of As detoxification mechanism in V. denseserrulata. Vacuolar As compartmentalization and formation of As-Phytochelatins/thiol complexes can be a part of As detoxification mechanisms in V. denseserrulata.

Study of Inheritance and Linkage of Virulence Genes in a Selfing Population of a Pakistani Dominant Race of Puccinia striiformis f. sp. tritici.

Wheat stripe rust is a severe threat of almost all wheat-growing regions in the world. Being an obligate biotrophic fungus, Puccinia striiformis f. sp. tritici (PST) produces new virulent races that break the resistance of wheat varieties. In this study, 115 progeny isolates were generated through sexual reproduction on susceptible Himalayan Berberis pseudumbellata using a dominant Pakistani race (574232) of PST. The parental isolate and progeny isolates were characterized using 24 wheat Yr single-gene lines and ten simple sequence repeat (SSR) markers. From the one-hundred-and-fifteen progeny isolates, 25 virulence phenotypes (VPs) and 60 multilocus genotypes were identified. The parental and all progeny isolates were avirulent to Yr5, Yr10, Yr15, Yr24, Yr32, Yr32, YrSp, YrTr1, YrExp2, Yr26, and YrTye and virulent to Yr1, Yr2, Yr6, Yr7, Yr8, Yr9, Yr17, Yr25, Yr27, Yr28, YrA, Yr44, and Yr3. Based on the avirulence/virulence phenotypes, we found that VPs virulent to Yr1, Yr2, Yr9, Yr17, Yr47, and YrA were controlled by one dominant gene; those to YrSp, YrTr1, and Yr10 by two dominant genes; and those to YrExp2 by two complementary dominant genes. The results are useful in breeding stripe rust-resistant wheat varieties and understanding virulence diversity.

Role of sepiolite for cadmium (Cd) polluted soil restoration and spinach growth in wastewater irrigated agricultural soil.

Metals that contaminate soil are one of the major problems seriously affecting sustainable agriculture worldwide. Cadmium (Cd) toxicity to agricultural crops is a global problem. Mobility of Cd in contaminated soil can be minimized by the amendment of soil passivators which will ultimately reduce its movement from soil to plants. A pot study was performed to evaluate the impact of sepiolite from 1% to 5% on Cd solubility and its accumulation in spinach tissues. Soil pH, Cd fractionation, Cd accumulation in spinach tissue and Cd adsorption mechanism were determined. Results were recorded that soil pH was increased from 0.3 to 1.0 units with the increasing rate of sepiolite from 1% to 5%. Similarly, Cd contents in acid soluble phase was decreased by 42.8% and increased in residual phase by 35.8% at 5% rate, relative to control. Moreover, the significant reduction in Cd uptake by spinach shoots and roots was occurred by 26.2% and 30.6% at 5% rate, respectively. Furthermore, the maximum Cd adsorption capacity 37.35 mg g-1 was recorded at 5% rate relative to control. The analysis of FTIR, XRD and SEM also confirm the ability of sepiolite for Cd polluted soil restoration and thereby, reduces its phytoavailability in polluted soil to alleviate food security challenges.

Assessment of health and ecological risks of heavy metal contamination: a case study of agricultural soils in Thall, Dir-Kohistan.

Heavy metal (HM) contamination in agricultural soils has been a significant health concern worldwide due to their persistent and non-biodegradable nature and biomagnification to higher trophic levels. The present study was conducted to assess Cd and Pb concentrations in soil samples collected from potato-growing areas in Thall, Dir-Kohistan, and to determine their associated health and ecological risks. The contamination factor calculated for Cd (0 to 1.74) and Pb (0 to 0.91) showed their moderate to low contamination in the study area. Geo-accumulation indices of Cd and Pb were less than 1, indicating moderate soil pollution of these HM in the study area. However, the ecological risk factor (Eri) of Cd was greater than 40 for only three soil samples, indicating the moderate potential of ecological risks of respective soils. The principal component analysis (PCA) and Pearson correlation suggested that the contamination in different soils was lithogenic followed by anthropogenic activities. The hazard quotient (HQ) in children and adults was found in the following order: dermal > ingestion > inhalation. Moreover, the values of HQ through various exposure routes were higher in children compared to adults, which showed that adults were at a lower level of risk associated with HM contamination. The results of the present study can serve as baseline data for government agencies related to environmental protection, which could devise policies to minimize Cd and Pb contamination in the agricultural soils.

Mycotoxin patulin in food matrices: occurrence and its biological degradation strategies.

Patulin is a mycotoxin produced by a number of filamentous fungal species. It is a polyketide secondary metabolite which can gravely cause human health problems and food safety issues. This review deals with the occurrence of patulin in major food commodities from 2008 to date, including historical aspects, source, occurrence, regulatory limits and its toxicity. Most importantly, an overview of the recent research progress about the biodegradation strategies for contaminated food matrices is provided. The physical and chemical approaches have some drawbacks such as safety issues, possible losses in the nutritional quality, chemical hazards, limited efficacy, and high cost. The biological decontamination based on elimination or degradation of patulin using yeast, bacteria, and fungi has shown good results and it seems to be attractive since it works under mild and environment-friendly conditions. Further studies are needed to make clear the detoxification pathways by available potential biosorbents and to determine the practical applications of these methods at a commercial level to remove patulin from food products with special reference to their effects on sensory characteristics of foods.

Identification of Berberis Species Collected from the Himalayan Region of Pakistan Susceptible to Puccinia striiformis f. sp. tritici.

Puccinia striiformis f. sp. tritici (Pst), the stripe rust pathogen infecting cereal crops and grasses, was believed to have a hemicyclic life cycle consisting of uredinial and telial stages before the recent discovery of barberry (Berberis spp.) as an alternate (aecial) host for the fungus. This discovery has improved the understanding of the biology of the stripe rust pathogen. The Himalayan and near-Himalayan regions of Pakistan, China, and Nepal are considered as the center of diversity for Pst pathogen. High genetic diversity has been reported in these areas, probably resulting from the sexual reproduction of the stripe rust fungus. To determine if Berberis species growing in Pakistan are susceptible to Pst, we collected seeds of five species and two subspecies from the Himalayan region in 2016 and inoculated the seedlings with germinated teliospores of a Pakistani Pst isolate under controlled conditions. Pycnia and aecia were produced on all inoculated plants of these species and subspecies, and were demonstrated as Pst by successful infection of wheat plants with aeciospores. This study showed that the tested Pakistani Berberis species and subspecies are susceptible to Pst under controlled conditions.

Biochar alleviates Cd phytotoxicity by minimizing bioavailability and oxidative stress in pak choi (Brassica chinensis L.) cultivated in Cd-polluted soil.

The production of leafy vegetables such as Brassica chinensis L. in cadmium (Cd)-polluted soil causes serious threats to human health and food safety around the globe. A pot culture was established to examine the efficacy of rice-straw induced biochar (applied to soil at the rate of 0%, 2.5% and 5%, w/w) on growth, gaseous exchange attributes, antioxidative capacities and Cd uptake in pak choi (Brassica chinensis L.), when soil was spiked with Cd (CdCl2) at 0, 5, 10 and 20 mg kg-1 soil. The results revealed that Cd stress significantly (P < 0.05) reduced plant biomass and physiological attributes, and accumulated higher Cd concentrations in plant tissues with the increasing rate of Cd concentration in the soil. However, incorporation of biochar at 5% application rate prominently increased the shoot (98.27%) and root (85.96%) dry biomass, net photosynthesis (45.52%), transpiration rate (161.34%), stomatal activity (111.76%) and intracellular CO2 concentration (32.25%) when Cd was added at 20 mg kg-1 soil, relative to the respective treatment without biochar. Whereas, incorporation of biochar at 5% significantly reduced the bioavailable Cd by 16.64% under 20 mg kg-1 soil, compared to respective Cd treatment without biochar.Similarly, Cd accumulation in shoots and roots was decreased by 42.49% and 29.23%, and thereby reduced leaf MDA and H2O2 contents by 21.45% and 31.28%, respectively, at 20 mg Cd kg-1 spiked soil relative to without biochar amended soil. An increment was noticed in the activities of guaiacol peroxidase (POD), superoxide dismutase (SOD), ascorbate peroxidase (APX), catalase (CAT) and glutathione (GSH) by 37.31%, 66.35%, 115.94%, 122.72% and 59.96%, respectively, with 5% biochar addition in 20 mg kg-1 Cd spiked soil. Moreover, biochar induced a synergistic impact on plants by increasing soil alkalinization and thereby reducing Cd phytotoxicity throughimmobilization. Overall, results proposed that rice-straw biochar has an ability to restore Cd polluted soil and increased pak choi production and thereby reduced food security risks in polluted soil.

Effective Role of Biochar, Zeolite and Steel Slag on Leaching Behavior of Cd and Its Fractionations in Soil Column Study.

Remediation of cadmium (Cd) from contaminated soils is considered a complicated task of environmental safety. A column leaching experiment was planned to estimate the influence of biochar (BC), zeolite (ZE) and steel slag (SL) at 1.5% and 3% application rate on Cd leaching behavior and chemical fractionation in contaminated soil. A sequential extraction procedure, the European Community Bureau of Reference (BCR), Toxicity Characteristic Leaching Procedure (TCLP) and NH4NO3 were performed after leaching was completed. The soluble portion of Cd was decreased by 36.3%, 18.4% and 28.7% and Cd contents in leachate were decreased by 44.8%, 30% and 31.3% after BC, ZE and SL addition at 3% rate, respectively over control soil. The greater reduction in TCLP extractable Cd was observed by 29.6% with BC and 22.4% with ZE and 25.7% with SL at 3% application rate. Overall, biochar can be considered an efficient soil amendment to reduce Cd leaching as well as increased its stabilization within soil profile.

Vanadium toxicity in chickpea (Cicer arietinum L.) grown in red soil: Effects on cell death, ROS and antioxidative systems.

The agricultural soil contaminated with heavy metals induces toxic effects on plant growth. The present study was conducted to evaluate the effects of vanadium (V) on growth, H2O2 and enzyme activities, cell death, ion leakage, and at which concentration; V induces the toxic effects in chickpea plants grown in red soil. The obtained results indicated that the biomass (fresh and dry) and lengths of roots and shoots were significantly decreased by V application, and roots accumulated more V than shoots. The enzyme activities (SOD, CAT, and POD) and ion leakage were increased linearly with increasing V concentrations. However, the protein contents, and tolerance indices were significantly declined with the increasing levels of V. The results about the cell death indicated that the cell viability was badly damaged when plants were exposed to higher V, and induction of H2O2 might be involved in this cell death. In conclusion, all the applied V levels affected the enzymatic activities, and induced the cell death of chickpea plants. Furthermore, our results also confirmed that vanadium ≥ 130 mg kg-1 induced detrimental effects on chickpea plants. Additional investigation is needed to clarify the mechanistic explanations of V toxicity at the molecular level and gene expression involved in plant cell death.