Kg-1 Treatment Research Articles

Main metabolic pathways of Solanum nigrum L. hyperaccumulating cadmium except of copper simultaneously through differentially expressed proteins analysis

Determining the hyperaccumulation mechanism of Solanum nigrum L., which exclusively accumulates cadmium (Cd), presents significant challenges due to the difficulty in identifying its unique characteristics. While some metabolic pathways related to Cd accumulation can be explored, there are no methods to ascertain if other heavy metals may share the same pathways. Isobaric tags for relative and absolute quantitation (iTRAQ) were employed to investigate the metabolic pathways associated with Cd hyperaccumulation and Cu accumulation (non-Cu hyperaccumulator) by comparing differentially expressed proteins (DEPs). The results showed that 27 intersecting DEPs reflecting relative metabolic pathways related to Cd accumulation were identified by comparing DEPs in leaves and roots, including carbon metabolism, aminoacyl-tRNA biosynthesis, phagosome, peroxisome, as well as starch and sucrose metabolism. These pathways might be responsible for the values of Cd enrichment factor (EF) and translocation factor (TF) exceeding 1, associated with key proteins participated in phosphoenolpyruvate, carboxylase, chloroplastic catalytic activity, and granule-bound starch synthase I. The combined metabolic pathways identified by 2 intersecting DEPs related to Cu accumulation could result in Cu EF >1 in the 0.2 Cu mg kg−1 treatment, EF <1 in the 5 mg kg−1 treatment, and TF<1 in both treatments, associated with key proteins, which might concern photosynthesis-antenna proteins and hydroxymethylbilane synthase. No metabolic pathways related to simultaneous accumulation of Cd and Cu has been identified. The identified DEPs were validated using Western blotting with five key proteins. Additionally, Western blotting and yeast mutant confirmed the presence of proteins related to carbon fixation in photosynthetic organisms, carbon metabolism, peroxisome, as well as starch and sucrose metabolism. Photosynthetic, O2•−, H2O2 and non-enzymatic antioxidants indices reflecting protein-related differences indirectly supported the above results. These findings are crucial for further exploration of the Cd hyperaccumulation mechanism.

Selenium in soil enhances resistance of oilseed rape to Sclerotinia sclerotiorum by optimizing the plant microbiome.

Plants can recruit beneficial microbes to enhance their ability to resist disease. It is well established that selenium is beneficial in plant growth, but its role in mediating microbial disease resistance remains poorly understood. Here, we investigated the correlation between selenium, oilseed rape rhizosphere microbes, and Sclerotinia sclerotiorum. Soil application of 0.5 and 1.0 mg kg-1 selenium [selenate Na2SeO4, Se(VI) or selenite Na2SeO3, Se(IV)] significantly increased the resistance of oilseed rape to Sclerotinia sclerotiorum compared with no selenium application, with a disease inhibition rate higher than 20% in Se(VI)0.5, Se(IV)0.5 and Se(IV)1.0 mg kg-1 treatments. The disease resistance of oilseed rape was related to the presence of rhizosphere microorganisms and beneficial bacteria isolated from the rhizosphere inhibited Sclerotinia stem rot. Burkholderia cepacia and the synthetic community consisting of Bacillus altitudinis, Bacillus megaterium, Bacillus cereus, Bacillus subtilis, Bacillus velezensis, Burkholderia cepacia, and Flavobacterium anhui enhanced plant disease resistance through transcriptional regulation and activation of plant-induced systemic resistance. In addition, inoculation of isolated bacteria optimized the bacterial community structure of leaves and enriched beneficial microorganisms such as Bacillus, Pseudomonas, and Sphingomonas. Bacillus isolated from the leaves were sprayed on detached leaves, and it also performed a significant inhibition effect on Sclerotinia sclerotiorum. Overall, our results indicate that selenium improves plant rhizosphere microorganisms and increase resistance to Sclerotinia sclerotiorum in oilseed rape.

Potential of Purslane (Portulaca oleracea L.) in Phytoremediation: A Study on the Bioaccumulation and Bio-Transfer of Cadmium, Nickel, and Copper in Contaminated Soils

As industrial and agricultural activities intensify and technology rapidly advances, soil pollution has escalated to alarming levels. The increasing contamination of agricultural areas and the crops cultivated therein has emerged as a significant contemporary issue. Phytoremediation, the use of plants to remove pollutants, is a promising method for mitigating soil heavy metal contamination. &#x0D; This study investigates the bioaccumulation capacity of purslane (Portulaca oleracea L.), a potential phytoremediator, in soils artificially contaminated with cadmium (Cd), nickel (Ni), and copper (Cu). Purslane was cultivated under controlled conditions with varying doses of Cd, Ni, and Cu. After 55 days, the plants were harvested and analysed for heavy metal concentrations in their roots, stems, and leaves. Results demonstrated a direct correlation between environmental heavy metal concentration and plant heavy metal content, with the most significant accumulation occurring in the roots. Leaf chlorophyll content was adversely affected by increased Cd, Ni, and Cu applications. The highest Cu, Ni, and Cd contents were found in the roots at 140 mg kg-1 Cu, 80 mg kg-1 Ni, and 20 mg kg-1 Cd applications, respectively. The bio-transfer coefficient (BTC), a measure of heavy metal transport from the root region to the leaves, was calculated. The BTC values ranged from 0.84-1.09 for Cu, 0.39-0.84 for Ni, and &gt;1 for Cd at the Control and 5 mg Cd kg-1 treatments. &#x0D; These findings suggest that purslane has potential for phytoremediation of heavy metal-contaminated soils, although the bioaccumulation and bio-transfer of heavy metals are dependent on the specific metal and its concentration in the soil. The study also highlights the potential risks associated with the consumption of plants grown in heavy metal-contaminated soils, as heavy metals can accumulate in different plant tissues, potentially entering the food chain.

Bear bile powder alleviates Parkinson's disease-like behavior in mice by inhibiting astrocyte-mediated neuroinflammation.

Parkinson's disease (PD) is a common neurodegenerative disease in middle-aged and elderly people. In particular, increasing evidence has showed that astrocyte-mediated neuroinflammation is involved in the pathogenesis of PD. As a precious traditional Chinese medicine, bear bile powder (BBP) has a long history of use in clinical practice. It has numerous activities, such as clearing heat, calming the liver wind and anti-inflammation, and also exhibits good therapeutic effect on convulsive epilepsy. However, whether BBP can prevent the development of PD has not been elucidated. Hence, this study was designed to explore the effect and mechanism of BBP on suppressing astrocyte-mediated neuroinflammation in a mouse model of PD. PD-like behavior was induced in the mice by intraperitoneal injection of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) (30 mg·kg-1) for five days, followed by BBP (50, 100, and 200 mg·kg-1) treatment daily for ten days. LPS stimulated rat C6 astrocytic cells were used as a cell model of neuroinflammation. THe results indicated that BBP treatment significantly ameliorated dyskinesia, increased the levels of tyrosine hydroxylase (TH) and inhibited astrocyte hyperactivation in the substantia nigra (SN) of PD mice. Furthermore, BBP decreased the protein levels of glial fibrillary acidic protein (GFAP), cyclooxygenase 2 (COX2) and inducible nitric oxide synthase (iNOS), and up-regulated the protein levels of takeda G protein-coupled receptor 5 (TGR5) in the SN. Moreover, BBP significantly activated TGR5 in a dose-dependent manner, and decreased the protein levels of GFAP, iNOS and COX2, as well as the mRNA levels of GFAP, iNOS, COX2, interleukin (IL) -1β, IL-6 and tumor necrosis factor-α (TNF-α) in LPS-stimulated C6 cells. Notably, BBP suppressed the phosphorylation of protein kinase B (AKT), inhibitor of NF-κB (IκBα) and nuclear factor-κB (NF-κB) proteins in vivo and in vitro. We also observed that TGR5 inhibitor triamterene attenuated the anti-neuroinflammatory effect of BBP on LPS-stimulated C6 cells. Taken together, BBP alleviates the progression of PD mice by suppressing astrocyte-mediated inflammation via TGR5.

Phenolic Profiles, Antihyperglycemic, Anti-Diabetic, and Antioxidant Properties of Egyptian Sonchus oleraceus Leaves Extract: An In Vivo Study.

This study aimed to investigate the phenolic and antioxidant properties of Egyptian Sonchus oleraceus leaves extract (SOE) while comparing the antihyperglycemic efficacy of SOE with that of conventional medicines (glibenclamide) in vivo as a substitution for insulin-deficient patients. Total phenolic (TPC) and flavonoid contents (TFC) in SOE contributed around 127.66 ± 0.56 mg GAE/gm as gallic acid equivalent (GAE) and 74.80 ± 0.55 mg QE/gm as quercetin equivalent (QE). SOE also showed significant DPPH scavenging activity at 43.46%. The presence of five phenolic and six flavonoid compounds in SOE was discovered by HPLC analysis. For the in vivo assay, 42 rats were distributed into six groups (7 Wister albino rats each). The standard control group was fed a basal diet. While the 35 rats were induced with a single dose of 100 mg kg-1 body weight (b.w.) alloxan, then treated orally with glibenclamide (GLI) at 10 mg kg-1, 100, 200, and 300 mg kg-1 SOE (positive control group) for 56 days of routine gastric oral gavages and compared to the effects of GLI, the treatment of SOE 200 and 300 mg kg-1 in diabetic rats for two months dramatically decreased blood glucose, total lipid, total cholesterol, and low-density lipoprotein cholesterol (LDLC) while boosting high-density lipoprotein cholesterol (HDLC) levels and improving liver and kidney functions. The histological assay revealed that the SOE 300 mg kg-1 treatment significantly improved the pancreas tissues, implying the potential application of Egyptian SOE as a diabetes treatment.

Tissue distribution of cadmium and its effect on reproduction in Spodoptera exigua

Vegetable fields are often contaminated by heavy metals, and Spodoptera exigua is a major vegetable pest which is stressed by heavy metals mainly by feeding. In this study, cadmium accumulation in the tissues of S. exigua exposed to cadmium and its effects on the growth and development of the parents and the offspring were investigated. Under the stress of different concentrations of cadmium (0.2, 3.2, and 51.2 mg kg–1), the cadmium content in each tissue of S. exigua increased in a dose-dependent manner. At the larval stage, the highest cadmium accumulation was found in midgut in all three cadmium treatments, but at the adult stage, the highest cadmium content was found in fat body. In addition, the cadmium content in ovaries was much higher than in testes. When F1S. exigua was stressed by cadmium and the F2 generation was not fed a cadmium-containing diet, the larval survival, pupation rate, emergence rate and fecundity of the F2 generation were significantly reduced in the 51.2 mg kg–1 treatment compared to the corresponding F1 generation. Even in the F2 generation of the 3.2 mg kg–1 treatment, the fecundity was significantly lower than in the parental generation. The fecundity of the only-female stressed treatment was significantly lower than that of the only-male stressed treatment at the 3.2 and 51.2 mg kg–1 cadmium exposure levels. When only mothers were stressed at the larval stage, the fecundity of the F2 generation was significantly lower than that of the F1 generation in the 51.2 mg kg–1 treatment, and it was also significantly lower than in the 3.2 and 0.2 mg kg–1 treatments. The results of our study can provide useful information for forecasting the population increase trends under different heavy metal stress conditions and for the reliable environmental risk assessment of heavy metal pollution.

Effects of Silicon Application on Arsenic Sequestration in Iron Plaque and Arsenic Translocation in Rice

The As sequestration by iron plaque and the As translocation in rice significantly affect the As accumulation in brown rice, and silicon (Si) application inhibits the As accumulation in rice plants. However, little information is available concerning the effect of Si application on As sequestration by iron plaque and translocation in rice. In this study, a pot experiment using As-contaminated paddy soil with different Si supply levels was conducted to investigate the effects of Si application on the As sequestration by iron plaque on the root surface and the As translocation from different tissues to brown rice. The results showed that the Si2 (0.66 g·kg-1) treatment significantly increased the activities of CAT (1.81 times), SOD (7.98 times), and POD (1.25 times) in the roots, increased the DCB-extractable Fe concentration (44.35%), and promoted the roughness of iron plaque (108.91%), resulting in a significant increase in the DCB-extractable As concentration of iron plaque (88.32%). Moreover, the Si2 treatment significantly promoted the As accumulation in the roots and inhibited the As translocation from the roots and leaves to the brown rice, leading to a significant decrease in the brown rice As concentration (53.12%). The increase in As sequestration by iron plaque with Si application was attributed to the enhancement of iron plaque formation and the promotion of surface roughness of iron plaque, whereas the inhibition of As translocation from the roots and leaves to the brown rice in the Si application treatment was closely related to the competition between Si with As for transporters and the promotion of As-thiol complex formation and As compartmentalization in vacuolar. These findings provide more insight into the mechanisms of As translocation in rice and will be helpful for exploring strategies to reduce rice grain As through Si supply in As-contaminated paddy fields in South China.

Transcriptome reveals the exposure effects of CeO2 nanoparticles on pakchoi (Brassica chinensis L.) photosynthesis.

In this study, soil-grown pakchoi after 2 weeks seedling cultivation were exposed to CeO2 nanoparticles (CeO2 NPs) at 0.7, 7, 70, and 350mgkg-1 for 30 days. Results showed that chlorophyll content and photosynthetic assimilation rate were decreased significantly under all treatments with the largest decrease of 34.16% (0.7mgkg-1 CeO2 NPs), however, sub-stomatal CO2 was increased dramatically under low dose of CeO2 NPs (0.7mgkg-1). There were 4576, 3548, 2787, and 2514 genes up/down regulated significantly by 0.7, 7, 70, and 350mgkg-1 CeO2 NPs, respectively, and 767 genes affected under all treatments. In addition, 0.7mgkg-1 CeO2 NPs up-regulated 10 chlorophyll synthesis genes, 20 photosynthesis genes, and 10 carbon fixation enzyme genes; while 350mgkg-1 CeO2 NPs down-regulated 5 photosynthesis genes and 28 auxin-activated genes. Among the key genes of photosynthesis, Ferredoxin-NADP reductase (PetH) was upregulated in 0.7, 7 and 70mgkg-1 treatments, while Photosystem II lipoprotein (Psb27) was downregulated under 7, 70 and 350mgkg-1 treatments. Top 20 metabolic pathways affected by CeO2 NPs including plant hormone, amino acids, and glutathione, and carbon metabolism These results provide information about utilizing CeO2 NPs more safely and effectively in the future.

Enrichment of the flavonoid fraction from Eucommia ulmoides leaves by a liquid antisolvent precipitation method and evaluation of antioxidant activities in vitro and in vivo.

Eucommia ulmoides leaves originate from the dry leaves of the Eucommia ulmoides plant. Flavonoids are the main functional components of Eucommia ulmoides leaves. Some flavonoids such as rutin, kaempferol and quercetin are rich in Eucommia ulmoides, and they have outstanding antioxidant efficacy. However, the poor water solubility significantly affects the bioavailability of flavonoids. In this study, we used a liquid antisolvent precipitation (LAP) method to enrich the main flavonoid fractions in Eucommia ulmoides leaves, and prepared nanoparticles by the LAP method to increase flavonoids' solubility and antioxidant properties. The technological parameters were optimized by Box-Behnken Design (BBD) software and were displayed as follows: (1) total flavonoids (TFs) concentration: 83 mg mL-1; (2) antisolvent-solvent ratio: 11; (3) deposition temperature: 27 °C. Under optimal processing conditions, the purity and recovery rate of TFs were 88.32% ± 2.54% and 88.08% ± 2.13%, respectively. In vitro experiments showed that the radical scavenging IC50 values for DPPH, ABTS, hydroxyl radicals and superoxide anions were 16.72 ± 1.07, 10.76 ± 0.13, 227.68 ± 18.23 and 335.86 ± 15.98 μg mL-1, respectively. In vivo studies showed that the obtained purified flavonoid (PF) (100, 200, 400 mg kg-1) treatment is able to improve CCl4-induced liver and kidney damage through adjusting, superoxide dismutase (SOD), catalase (CAT), glutathione (GSH), glutathione peroxidase (GSH-Px) and malondialdehyde (MDA) levels. These results demonstrated that the LAP method is capable of extracting TFs from Eucommia ulmoides leaves with high bioaccessibility.

Sulfur enhances cadmium bioaccumulation in Cichorium intybus by altering soil properties, heavy metal availability and microbial community in contaminated alkaline soil.

Cadmium (Cd) contamination seriously threatens the soil health and food safety. Combination of amendment and accumulator plant is a green and effective technique to improve phytoremediation of Cd-contaminated alkaline soil. In this study, a potting experiment was conducted to investigate the effect of sulfur on Cd phytoextraction by Cichorium intybus (chicory). Soil chemical and microbial properties were determined to reveal the mechanism of sulfur-assisting Cd phytoremediation by chicory. Soil pH decreased from 7.77 to the lowest 7.30 with sulfur addition (0.6, 0.9 and 1.2 g kg-1, LS, MS and HS treatment); Electric conductivity, sulfate anion and available cadmium concentration increased gradually with increasing sulfur doses. Cd concentration of shoot and root significantly increased from 1.47 to 4.43 mg kg-1, 6.15 to 20.16 mg kg-1 by sulfur treatment relative to CK, which were attributed to increased available Cd concentration induced by decreased pH. Sulfur treatments significantly increased the Cd bioconcentration factor by 64.1%, 118.6%, 201.0% for shoot, 76.3%, 145.6% and 227.7% for root under LS, MS and HS relative to CK treatment, respectively (P < 0.05). However, only MS treatment significantly improved the Cd removal efficiency by 82.9% in comparison of CK treatment (P < 0.05). Microbial community diversity measured by 16SrRNA showed that Thiobacillus and Actinobacteria were the key and dominant strains of soil microbial communities after sulfur addition, which played a pivotal role in the process of sulfur oxidation involved in decrease of soil pH and the transformation of Cd forms. Correlation analysis and path analysis by structural equation model indicated that soil sulfate anion and Thiobacillus directly affected Cd removal efficiency by chicory in Cd-contaminated alkaline soil. This suggests that combination of sulfur and chicory may provide a way to promote Cd bioaccumulation for phytoremediation of Cd-contaminated alkaline soil.

Enhancement of soil physical properties and soil water retention with biochar-based soil amendments.

The soil physical properties are deteriorating due to changing rainfall patterns and intensities, as well as climate change-induced temperature fluctuations. Pot experiments were carried out to examine the impacts of synthesized soil amendments on soil water retention and plant growth. Soil amendments (biochar, polyacrylamide (PAM), and moringa) were used at different rates (0 (control), 2.1, 4.2, and 8.3 g kg-1) to improve the physical properties of the soil. As a result of soil amendment application, it was found that the mean weight diameter of soil aggregate increased by 188% during the 8.3 g kg-1 treatment, forming stable soil particles. Soil water retention improved by up to 128.9% during the 8.3 g kg-1 treatment, and it was analyzed that it was due to the high surface area of biochar, porosity, and high molecular weight of PAM. Pellet treatment increased all plant growth parameters (height, stem diameter, leaf number, and fresh and dry weight) for both beans and maize. The dry weight of beans (C3 plant) and maize (C4 plant) increased by 92.9 and 146.4%, respectively in an 8.3 g kg-1 pot. The soil physical condition was stabilized by the high carbon content of biochar and the improvement of soil coagulation between PAM and moringa. This had a positive effect on the C4 plant. The findings of this study indicate that if the soil amendments are properly mixed and applied based, they will improve soil stability and plant productivity.

Effect of Lippia grata essential oil as a feed additive on the performance of tambatinga juveniles

ABSTRACT Lippia grata (formerly known as Lippia gracillis) is an aromatic plant native to Brazil, with leaves rich in essential oils that possess significant biological activities. We evaluated the effect of essential oil of L. grata (EOLG) as a dietary additive on the growth, somatic indices, and biochemical parameters of juveniles (5.25 ± 0.26 g) of tambatinga, a hybrid fish obtained by crossing tambaqui (Colossoma macropomum) with pirapitinga (Piaractus brachypomum) of great economic importance in north and northeastern Brazil. We evaluated four dietary treatments, consisting of EOLG supplemented at 0.0, 0.5, 1.0, and 2.0 mL kg-1, over 60 days. Carcass yield was significantly higher in fish fed all EOLG diets compared to those fed the control diet (0.0 mL kg-1). Animals that received the 0.5 mL kg-1 treatment gained significantly more weight and showed a higher specific growth rate than those treated with 1.0 and 2.0 ml kg-1 EOLG, although none differed significantly from the control. The feed conversion rate was significantly lower in the 0.5 than in the 1.0 mL kg-1 treatment. Compared with higher concentrations, the diet containing 0.5 mL kg-1 EOLG increased the use of muscle glycogen, glucose, and lactate to meet energy demands, avoiding the use of muscle protein. Our results suggest that dietary supplementation with EOLG significantly improves carcass yield in tambatinga juveniles but that concentrations above 0.5 mL kg-1 may compromise growth rates and carbohydrate metabolism in this fish.

Distinctive quality control method for solid-state fermented Isaria cicadae from strain Ic-17-7 and application in a rat model of type 2 diabetes.

This work was aimed to establish a quality control method for evaluating the effects on glucose and lipids of the fruiting body of Isaria cicadae Miquel from strain Ic-17-7 (Ic-17-7fb) using a rat model of type 2 diabetes (T2DM). Random amplified polymorphic DNA, sequence-characterized amplified region, and high-performance liquid chromatography (HPLC) were used for the quality control of Ic-17-7fb. The pharmacological effects on streptozocin (STZ)-induced high fat diet (HFD)-fed Albino Wistar rats were evaluated. The rats underwent the following treatments: control, metformin, Ic-17-7fb (0.166 and 0.5 g·kg-1) or without treatment. The fasting blood glucose (FBG), blood glucose, total cholesterol (TC), triglyceride (TG), high-density lipoprotein (HDL-c), and low-density lipoprotein (LDL-c) were measured. Ic-17-7fb amplified a single specific band by S11-2-F3 and S11-2-R3 primers. An HPLC-based quality and quantity method was established for industrial application. The contents of adenosine and N6-(2-hydroxyethyl) adenosine (HEA) of the cultivated Ic-17-7fb were analyzed. All of the validation lots of cultured Ic-17-7fb passed the quantity control of the training set (0.90 mg·g-1 of adenosine and 0.89 mg·g-1 of HEA). After two weeks of administration, the average FBG was 4.89 ± 0.42 (control), 26.10 ± 5.77 (model), 23.63 ± 6.15 (metformin), 17.96 ± 9.36 (Ic-17-7fb for 0.166 g·kg-1), and 19.69 ± 8.71 mmol·L-1 (Ic-17-7fb for 0.5 g·kg-1). The FBG of Ic-17-7fb (0.166 g·kg-1) treatment significantly reduced by 31.19%, compared with the model after two weeks of administration (P < 0.01). Metformin, Ic-17-7fb (0.166 g·kg -1), and Ic-17-7fb (0.5 g·kg-1) reduced TC, TG, HDL-c, and LDL-c compared with the T2DM model treatment at the 6th week of treatment (P < 0.05). This study established the first quality standard for Ic-17-7fb, which can be effectively applied in the treatment of T2DM. The reliable quality control method and pharmacological effect will broaden its application space.

Determination of the Effects of Copper (Cu) and Lead (Pb) Heavy Metals on Soil Carbon and Nitrogen Mineralization

Heavy metal (HM) pollution has become one of the most important environmental problems of the present day, as a result of the developing industrial activities. Accordingly, it is important to understand microorganism activities in soil ecosystems that have been exposed to HMs for a long time. The aim of this study was to show the potential effects of ores on soil carbon and nitrogen mineralizations which were taken from copper (Cu) and lead (Pb) mines in Balıkesir-Balya and Kastamonu-Küre districts in Turkey. The carbon (C) and nitrogen (N) mineralizations were determined by using the CO2 respiration method (30 days) and the Parnas Wagner method (42 days) under the controlled laboratory conditions (28 °C, 80% of field capacity), respectively. It was observed that carbon mineralization decreased depending on the dose increase. 250 mg kg-1 treatment with Pb was lower than the control and there was a significant difference between them (P &lt; 0.001). In terms of nitrogen mineralization rate (%), there was no significant difference among all treatments. According to the results, Pb affected microorganisms more negatively; however, the presence of Cu slightly decreased its negative effect. It is possible to conclude that carbon mineralization can be indicator for HM pollution in the soil. However, nitrogen mineralization was not a determining factor at HM pollution in this study.

Using nano-scale Fe0 particles and organic waste to improve the nutritional status of tree seedlings growing in heavy metal-contaminated soil

The rehabilitation of heavy metal-contaminated lands is a challenging issue worldwide. The application of effective eco-friendly techniques and materials is necessary for amending the contaminated soils, and the in-situ results should be examined. The present study investigated the effect of zero-valent iron-nanoparticles (Fe0-NPs) and cellulosic wastes (CW) on the lead (Pb) and cadmium (Cd) uptake and nutrients’ (N, P, K) concentration of maple seedlings in contaminated soil. First, one-year-old seedlings were planted in pots containing unpolluted soil (volume = 3 Kg), and then the soil was contaminated by adding Pb (0, Pb100, Pb200, and Pb300 mg kg-1) and Cd (0, Cd10, Cd20, and Cd30 mg kg-1) solutions. The CW (0, 10, 20, 30 g/100g soil) and Fe0-NPs (0, 1, 2, 3 mg kg-1) treatments were applied to the soil before and after Pb and Cd addition, respectively. The biomass of seedlings and the concentration of nitrogen, potassium, and phosphorus in leaves were measured. Leaves, stems, and roots were digested to measure the Pb and Cd concentrations. Results showed that CW and Fe0-NPs improved N, P, and K concentrations in leaves at all levels of contamination. The lowest concentration of Pb and Cd in all organs and treatments was observed in the highest level of Fe0-NPs. The cellulosic waste and Fe0-NPs (the highest level only) significantly increased the soil pH at all levels of contamination. Our findings suggested that the use of Fe0-NPs (3 mg kg-1) and CW (30g/100g soil) could be appropriate for reducing the bioavailability of Pb and Cd in contaminated soil and improving the growth of maple seedlings.

Integrated biomarker responses of rice associated with grain yield in copper-contaminated soil

Copper (Cu) contamination in soil is an environmental issue that affects rice growth and development. This study investigated changes in photosynthetic capacities in combination with integrated biomarker responses at different growth stages of rice (Oryza sativa L. var. Hom Bai Toey) exposed to various concentrations of Cu. A randomized complete block design with four replications was used. Exposure to high copper concentrations of 200 Cu mg kg-1 of soil and more resulted in a marked decline in the photosynthetic efficiency of Photosystem II (Phi2) but increased yield of non-photochemical quenching (PhiNPQ) and yield of non-regulatory energy dissipation (PhiNO) at tillering and flowering stages. In addition, these concentrations induced a delay in the flowering of rice, as a consequence of stress experienced in early growth stage. Significant lipid peroxidation and leaf area reduction were observed with 400 Cu mg kg-1 treatment at flowering stage. Rice grain yield decreased significantly at copper concentrations of 200 and 400 mg kg-1. Overall, excess copper inhibited photosynthetic capacity, growth, and development of rice in the early growth stage, and synergistic effects of yield components contributed to final grain yield reduction at harvesting stage. In addition, calculated integrated biomarker response (IBR) values reflect well the severity of Cu toxicity with a decreasing order from tillering stage to harvesting stage.

Effect of different phosphorus sources applied with phosphate solubilizing bacteria on bio-geochemical properties and phosphorus release pattern in vertisol

Various phosphorus (P) fertilizers are used for crop production in different types of soil. But there is a knowledge gap in choosing the right source and form of P fertilizers to enhance the applied fertilizer use efficiency. An experiment was taken to identify the best phosphorus source and its effectiveness as a source of P in vertisol to unravel this problem of selecting suitable P fertilizer. With this background, an incubation experiment was conducted under laboratory condition to determine the phosphorus release pattern of different P sources [Single Super Phosphate (SSP), Rock Phosphate (RP), Diammonium Phosphate (DAP), Nano phosphate (Nano P), Phosphocompost (PC)] applied with phosphate solubilizing bacteria (PSB) and their influence on biogeochemical properties in vertisol. Experimental results emphasized that P release from different sources was influenced by soil pH, electrical conductivity (EC), cation exchange capacity (CEC), soil organic carbon (SOC), and microbial population. Applied P sources significantly(p=0.05) influenced the CEC, SOC, and microbial population except for soil pH and Ec. The maximum release in available P was obtained at 30 and 60 days after incubation with SSP +PSB (35.8 and 40.1 mg kg-1) and Nano P + PSB (33.9 and 38.6 mg kg-1) applied treatments, respectively.Whereas at 90 days after incubation Nano P + PSB (42.3 mg kg-1) and Phosphocompost + PSB (40.4 mg kg-1) treatments recorded the maximum P availability and minimum P (15.2, 13.9 and 11.8 mg kg -1) release was noticed in the control treatment throughout the period of incubation. It was evident that SSP or Nano P along with PSB application might be the best P source for Vertisol.

PHYTOREMEDIATION OF URANIUM TAILINGS: ROLE OF CHELATORS IN TRIGGERING URANIUM ACCUMULATION IN WHEAT

Chelator-assisted phytoextraction has been proposed as a potential tool for phytoremediation of uranium contaminated tailings. The purpose of the present investigation was to test the efficiency of the four various chelators namely, citric acid (CA), oxalic acid (OA), NTA and EDTA and to screen out the most effective chelator with promising concentration of it in increasing the U uptake and accumulation for phytoremedial programmes. Three kilograms of mixture (25:75; tailing: garden soil) was filled in the earthen pots. Treatment pots were prepared by applying- 0.1, 0.5, 2.5 and 12.5 mmol kg-1 concentrations of each of the chelator (CA, OA, NTA and EDTA). Optimum concentrations of the chelators were recorded considering biomass production, tolerance index and U uptake. Each chelator produced severe toxicity symptoms at 12.5 mmol kg-1 treatment level. Lowest depression in respect of growth was observed with NTA while OA and CA were proved less toxic than EDTA. Highest inhibition was recorded in EDTA treatments at respective levels. U uptake and accumulation was concentration dependent for each of the chelator amendment. Maximum U uptake (3.4-fold) in the roots occurred at 2.5 mmol kg-1 of CA while NTA proved to be the weakest for the same purpose. Not with standing, EDTA and NTA are stronger complexion agents than CA but in contrary, the use of CA proved beneficial in U tailing phytoremediation in the present investigation. The growth of the wheat plants was affected by each of the chelator, which in general follows the order: NTA ? OA ? CA ? EDTA, whereas the order for U accumulation was recorded as- CA &gt; EDTA &gt; OA &gt; NTA. On the basis of this study it can be suggested that the use CA over EDTA is better, as it is easily biodegradable, less toxic and has lower leaching risk..

Effects of Different Exogenous Selenium Species Application on Growth and Cadmium Uptake of Pak Choi in Cadmium Contaminated Soil

This study explored the discrepancy in the detoxification effects of different exogenous selenium (Se) species in cadmium (Cd)-contaminated soil to provide a scientific basis for the control of Cd pollution in the soil and the safe production of crops. A pot experiment was conducted to compare the effects of different concentrations (0, 0.5, 1.0, and 2.5 mg·kg-1) of selenite and selenate on the growth (root length, shoot height, biomass, and photosynthetic parameters), uptake, and translocation of Cd on pak choi in Cd-contaminated soil. The results indicated that the detoxification effect of a low Se concentration (≤1.0 mg·kg-1) treatment on Cd was better than that with a high Se concentration (2.5 mg·kg-1) treatment, and the selenite treatment demonstrated a greater detoxification effect on Cd than the corresponding selenate treatment. Meanwhile, the application of low-concentration selenite and selenate both increased the SPAD value, Pn, Gs, Ci, biomass, and shoot length of the pak choi, and the 1.0 mg·kg-1 selenite treatment had the most significant (P<0.05) effect (except Ci). Nevertheless, the photosynthetic parameters of the pak choi under the high-concentration Se were significantly lower than those under the low Se concentration treatment (except Tr, P<0.05). Compared with the treatment without Se (control), the uptake of Cd in the pak choi was reduced under different Se treatments. Compared with the control, the Cd concentration in the shoots of the pak choi treated with 1.0 mg·kg-1 of selenite and selenate decreased by 40.0% and 20.5% (P<0.05), respectively. In addition, the translocation of Cd from the root to the shoot was significantly reduced under the 0.5 mg·kg-1 selenate treatment, while the high-concentration treatments of either exogenous Se promoted the translocation of Cd. Overall, applying the appropriate amount of exogenous Se could promote the photosynthesis and biomass of pak choi, and reduce the accumulation of Cd in pak choi. Therefore, the 1.0 mg·kg-1 selenite treatment is recommended for the control and safe utilization of Cd in Cd-contaminated soil.

Quantifying soil N2O emissions from soil and anaerobically digested swine manure, nitrification and denitrification using 15N isotope labeling method.

Increasing use of anaerobically digested swine manure in the farmland makes it necessary to understand its impact on N2O emissions, regarding the source of N2O and the corresponding mechanism of action. We used a 15N-labeled sulfate modifying the soil in order to identify the sources of N2O and the pathways of nitrification and denitrification. Three soil moisture contents (50% WHC, 75% WHC, and 100% WHC) along with three levels of anaerobically digested swine manure (0 g·kg-1, 10 g·kg-1, and 25 g·kg-1) were tested using randomized block design. Although the combined effect of contents of anaerobically digested swine manure and the soil moisture contents added to the system stimulated the utilization of soil N and promoted denitrification, the process of nitrification dominated. In anaerobically digested swine manure-treated soils, the rate of contribution of anaerobically digested swine manure to N2O accounted for 68.6-99.8%. In the 25 g·kg-1 treatment, the maximum of N2O produced by denitrification and nitrification were 14.1% and 93.1%.