Utilization of organic-residues as potting media: Physico-chemical characteristics and their influence on vegetable production.

Soilless agriculture is acknowledged worldwide because it uses organic leftovers as a means of supporting intensive and efficient plant production. However, the quality of potting media deteriorates because of lower nutrient content and excessive shrinkage of most organic materials. A current study was undertaken to identify the optimal blend of locally available organic materials with desirable qualities for use as potting media. Therefore, different ingredients, viz., Pinus roxburghii needles, sugarcane bagasse, and farmyard manure were used alone or in combination as potting media to test their suitability by growing spinach as a test crop. Results showed that an increase in Pinus roxburghii needles and sugarcane bagasse decreased medium pH and electrical conductivity. Higher pH and electrical conductivity were recorded for the treatments having a higher farmyard manure ratio (≥50%) in combination. Except for pine needles 100%, pH and electrical conductivity were in the recommended range. The growth attributes include, leaves plant-1, shoot length, fresh- and dry shoot weight along with plant macronutrients (nitrogen, phosphorous, and potassium) and micronutrients (iron, copper, manganese, and zinc) content were higher in treatment pine needles 50%+farmyard manure 50% followed by pine needles 25%+farmyard manure 50%+sugarcane bagasse 25%. Moreover, the particular treatment of pine needles 50%+farmyard manure 50% exhibited the highest concentrations of macro- (nitrogen, phosphorus, and potassium) as well as micronutrients (iron, copper, manganese, and zinc) in the potting media following the harvest. This study highlights the potential of utilizing agro-industrial litter/waste as a soilless growing medium for spinach production under greenhouse conditions. When employed in appropriate proportions, this approach not only addresses disposal concerns but also proves effective for sustainable cultivation. Further research is needed to investigate the use of these wastes as potting media by mixing various particle-size ingredients.

Exopolysaccharide-producing bacterial cultures of Bacillus cereus and Pseudomonas aeruginosa in soil augment water retention and maize growth.

Land productivity in arid and hot climate regions is constrained by water scarcity due to low rainfall and organic matter, which limit both soil-water retention and crop yields. Main objective of this research was to explore the potential of exopolysaccharide (EPS) producing bacteria screened from different soils for enhancing soil-water retention, phosphorus solubilization and maize growth. Twelve soil samples were drawn from diverse ecologies (sub-humid and arid) to isolate EPS-producing bacteria (EPB), and cultured on LB and Pikovskaya media. Nine bacterial strains were found to have EPS production characteristic; among from them, 2 most efficient EPB strains were selected and characterized through morphological, biochemical and molecular standard procedures of bacterial identification. These potent EPB-strains were characterized as Pseudomonas aeruginosa EPB9 and Bacillus cereus EPB17. Broth cultures of 2 and 10 days old (2d and 10d) both EPB strains were used as soil inoculant to grow maize in growth chamber under triplicated factorial CRD. Treatments were: Control, LB broth (without inoculum), EPB9-2d, EPB9-10d, EPB17-2d, and EPB17-10d inoculation in both non-stressed and drought-stressed soils. Experiment lasted for 24 days, when soil and plant leaf water contents, plant growth attributes and antioxidant enzymes were measured. Inoculation of both EPB strains significantly enhanced maize growth and soil-water retained until harvesting stage. Higher water contents in soil and plant leaves, as well as fresh shoot and root weight were with EPB9-10d. Plant leaf area and shoot length were greater with EPB17-10d inoculation. Bacterial EPS also caused higher protein and sugar, and lower proline contents in plants. Antioxidant enzymes (SOD, POD and CAT) remained lower with both EPB treatments due to reduced drought stress than in control. It was evident that efficient EPB strains could survive even under osmotic stress, and retain more soil-water for longer time. Further, antioxidant enzymes and EPS interact together for drought tolerance and growth promotion of plants. Therefore, study concludes that under limited water conditions, soil inoculation with bacterial cultures having the characteristics of greater EPS production and antioxidative enzyme system bears the potential of improving land productivity.

Genome-Wide Identification, and In-Silico Expression Analysis of YABBY Gene Family in Response to Biotic and Abiotic Stresses in Potato (Solanum tuberosum).

YABBY is among the specific transcription factor (TF) gene family in plants and plays an important role in the development of the leaves and floral organs. Its specific roles include lateral organ development, the establishment of dorsoventral polarity, and response to abiotic stress. Potato is an important crop worldwide and YABBY genes are not still identified and characterized in potato. So, little has been known about YABBY genes in potato until now. This study was carried out to perform genome-wide analysis, which will provide an in-depth analysis about the role of YABBY genes in potato. There have been seven StYAB genes identified, which are found to be located on seven different chromosomes. Through multiple sequence analyses, it has been predicted that the YABBY domain was present in all seven genes while the C2-C2 domain was found to be absent only in StYAB2. With the help of cis-element analysis, the involvement of StYAB genes in light, stress developmental, and hormonal responsiveness has been found. Furthermore, expression analysis from RNA-seq data of different potato organs indicated that all StYAB genes have a role in the vegetative growth of the potato plant. In addition to this, RNA-seq data also identified StYAB3, StYAB5, and StYAB7 genes showing expression during cadmium, and drought stress, while StYAB6 was highly expressed during a viral attack. Moreover, during the attack of Phytophthora infestans on a potato plant StYAB3, StYAB5, StYAB6, and StYAB7 showed high expression. This study provides significant knowledge about the StYAB gene structures and functions, which can later be used for gene cloning, and functional analysis; this information may be utilized by molecular biologists and plant breeders for the development of new potato lines.

Reimagining safe lithium applications in the living environment and its impacts on human, animal, and plant system.

Lithium's (Li) ubiquitous distribution in the environment is a rising concern due to its rapid proliferation in the modern electronic industry. Li enigmatic entry into the terrestrial food chain raises many questions and uncertainties that may pose a grave threat to living biota. We examined the leverage existing published articles regarding advances in global Li resources, interplay with plants, and possible involvement with living organisms, especially humans and animals. Globally, Li concentration (<10-300 mg kg-1) is detected in agricultural soil, and their pollutant levels vary with space and time. High mobility of Li results in higher accumulation in plants, but the clear mechanisms and specific functions remain unknown. Our assessment reveals the causal relationship between Li level and biota health. For example, lower Li intake (<0.6 mM in serum) leads to mental disorders, while higher intake (>1.5 mM in serum) induces thyroid, stomach, kidney, and reproductive system dysfunctions in humans and animals. However, there is a serious knowledge gap regarding Li regulatory standards in environmental compartments, and mechanistic approaches to unveil its consequences are needed. Furthermore, aggressive efforts are required to define optimum levels of Li for the normal functioning of animals, plants, and humans. This review is designed to revitalize the current status of Li research and identify the key knowledge gaps to fight back against the mountainous challenges of Li during the recent digital revolution. Additionally, we propose pathways to overcome Li problems and develop a strategy for effective, safe, and acceptable applications.

Exposure of cherry radish (Raphanus sativus L. var. Radculus Pers) to iron-based nanoparticles enhances its nutritional quality by trigging the essential elements.

Iron (Fe) deficiency is a pervasive nutritional disorder, and producing vegetables enriched with Fe as a dietary source is imperative. Herein, Fe3O4, FeO(OH), α-Fe2O3, ß-Fe2O3, γ-Fe3O4, and nZVI nanoparticles (NPs) were applied in soil as fertilizer to enhance the Fe nutrition in cherry radish. The highest enhancement of Fe content (58%) was observed in Fe3O4 treatment at 100 mg kg-1, followed by FeO(OH) (49%), α-Fe2O3 (24%), nZVI (14%), ß-Fe2O3 (13%) and γ-Fe3O4 (4%). The daily intake of Fe was 97-104% and 77-91% with Fe3O4 and FeO(OH) at 100-200 mg kg-1, respectively. Moreover, the zinc, vitamin C and crude protein contents were also increased by 37, 48 and 67% under Fe3O4 treatment as compared to control. Fe3O4 at 100 mg kg-1 also increased the essential amino acids (phenylalanine, leucine and isoleucine) contents by 11-14%. These data suggest that Fe3O4 and FeO(OH) NPs could be effective nanofertilizers to enhance Fe nutrition in plants.

Stress signaling convergence and nutrient crosstalk determine zinc-mediated amelioration against cadmium toxicity in rice.

Consumption of rice (Oryza sativa L.) is one of the major pathways for heavy metal bioaccumulation in humans over time. Understanding the molecular responses of rice to heavy metal contamination in agriculture is useful for eco-toxicological assessment of cadmium (Cd) and its interaction with zinc (Zn). In certain crops, the impacts of Cd stress or Zn nutrition on the biophysical chemistry and gene expression have been widely investigated, but their molecular interactions at transcriptomic level, particularly in rice roots, are still elusive. Here, hydroponic investigations were carried out with two rice genotypes (Yinni-801 and Heizhan-43), varying in Cd contents in plant tissues to determine their transcriptomic responses upon Cd15 (15 µM) and Cd15+Zn50 (50 µM) treatments. High throughput RNA-sequencing analysis confirmed that 496 and 2407 DEGs were significantly affected by Cd15 and Cd15+Zn50, respectively, among which 1016 DEGs were commonly induced in both genotypes. Multitude of DEGs fell under the category of protein kinases, such as calmodulin (CaM) and calcineurin B-like protein-interacting protein kinases (CBL), indicating a dynamic shift in hormonal signal transduction and Ca2+ involvement with the onset of treatments. Both genotypes expressed a mutual regulation of transcription factors (TFs) such as WRKY, MYB, NAM, AP2, bHLH and ZFP families under both treatments, whereas genes econding ABC transporters (ABCs), high affinity K+ transporters (HAKs) and Glutathione-S-transferases (GSTs), were highly up-regulated under Cd15+Zn50 in both genotypes. Zinc addition triggered more signaling cascades and detoxification related genes in regulation of immunity along with the suppression of Cd-induced DEGs and restriction of Cd uptake. Conclusively, the effective integration of breeding techniques with candidate genes identified in this study as well as economically and technologically viable methods, such as Zn nutrient management, could pave the way for selecting cultivars with promising agronomic qualities and reduced Cd for sustainable rice production.

A critical review of the environmental impacts of manufactured nano-objects on earthworm species.

The presence of manufactured nano-objects (MNOs) in various consumer or their (future large-scale) use as nanoagrochemical have increased with the rapid development of nanotechnology and therefore, concerns associated with its possible ecotoxicological effects are also arising. MNOs are releasing along the product life cycle, consequently accumulating in soils and other environmental matrices, and potentially leading to adverse effects on soil biota and their associated processes. Earthworms, of the group of Oligochaetes, are an ecologically significant group of organisms and play an important role in soil remediation, as well as acting as a potential vector for trophic transfer of MNOs through the food chain. This review presents a comprehensive and critical overview of toxic effects of MNOs on earthworms in soil system. We reviewed pathways of MNOs in agriculture soil environment with its expected production, release, and bioaccumulation. Furthermore, we thoroughly examined scientific literature from last ten years and critically evaluated the potential ecotoxicity of 16 different metal oxide or carbon-based MNO types. Various adverse effects on the different earthworm life stages have been reported, including reduction in growth rate, changes in biochemical and molecular markers, reproduction and survival rate. Importantly, this literature review reveals the scarcity of long-term toxicological data needed to actually characterize MNOs risks, as well as an understanding of mechanisms causing toxicity to earthworm species. This review sheds light on this knowledge gap as investigating bio-nano interplay in soil environment improves our major understanding for safer applications of MNOs in the agriculture environment.

Performance and microbial community dynamics in anaerobic continuously stirred tank reactor and sequencing batch reactor (CSTR-SBR) coupled with magnesium-ammonium-phosphate (MAP)-precipitation for treating swine wastewater.

The impacts of magnesium-ammonium-phosphate (MAP) precipitation on the performance and microbial dynamics in an anaerobic continuously stirred tank reactor (CSTR) coupled with sequencing batch reactor (SBR) for swine wastewater treatment were investigated. In CSTR-SBR systems, an overall higher removal efficiency for COD, NH4+ and PO43-as 98.6%, 98.7% and 97.9% was achieved with MAP precipitation, compared to CSTR-SBR without MAP pretreatment (i.e., 97.5, 74.3% and 19.9% for COD, NH4+ and PO43-, respectively). With MAP precipitation, the high C/N ratio of 6.6 after anaerobic CSTR was observed. The increase in the richness and diversity of microbial communities in CSTR with MAP was conducive to nitrogen and phosphorus removal, as well as biogas production. The core community was affiliated with bacterial phyla Firmicutes, Bacteroidetes, Proteobacteria, Cloacimonetes, and Spirochaetae. The study provide a new insight into the potential application of MAP precipitation as pretreatment for dealing with nutrient recovery from high-strength swine wastewater.

Physiological and biochemical response of wheat (Triticum aestivum) to TiO2 nanoparticles in phosphorous amended soil: A full life cycle study.

Nanoparticles (NPs) application in soil as nano-fertilizers to increase crop yield is getting attention due to their higher efficiency and less environmental risks. This study investigated the interactive effects of variable titanium dioxide nanoparticles (TiO2-NPs) levels (0, 30, 50 and 100 mg kg-1) superimposed to phosphorus (P) fertilizer application in soil at the rates of 0, 25 and 50 mg kg-1 on wheat crop. Physiological parameters of plants, their antioxidant enzymes activities (SOD, POD), and contents of crude protein, H2O2, MDA and metals/nutrients (Al, Ca, Mg, Fe, Zn and Cu) were measured. Data on physiological traits revealed that application of 50 mg kg-1 of TiO2-NPs without P fertilizer significantly enhanced the root and shoot length by 63 and 26%, respectively. Increased contents of nutrients in the shoots, viz., Ca (316%), Cu (296%), Al (171%) and Mg (187%) with 50 mg kg-1 TiO2-NPs treatment reflected improvement in crop growth and grain quality. Furthermore, P contents in plant tissues were raised up to 56% with 50 mg kg-1 of TiO2-NPs even in the absence of P fertilizer. In the soil, concentration of phytoavailable P was significantly increased up to 63.3% in the presence of 50 mg kg-1 TiO2-NPs as compared to control. Contents of crude protein in grain were also enhanced by 22.8% (at P50) and 17.4% (at P25) with 50 mg kg-1 TiO2-NPs application. Along with P application, TiO2-NPs triggered the activities of SOD (2.06-33.97%) and POD (up to 13.19%), and H2O2 production (50.6-138.8%). However, MDA contents were not elevated significantly at any level of TiO2-NPs, and remained at par with control. It was noteworthy that highest level of TiO2-NPs, viz., 100 mg kg-1 exhibited plant and nutrients response lower than that with 50 mg kg-1. Further, TiO2-NPs triggered the bioavailability of micronutrient heavy metals (Zn, Cu and Fe) and Al, which could have toxicity at higher concentrations. These results suggested that TiO2-NPs might have some affinities with phosphate compounds and metal ions in the soil to bring them in soluble form, which enhanced their bioavailability. Although it improved the crop yield and quality, but toxic or negative impact of TiO2-NPs was also apparent at higher dose. Therefore, investigations on the potential interactions of NPs with other nutrients and toxic metals are needed to enhance our understanding for the safer application of nano-fertilizer.

Zinc alleviates cadmium toxicity by modulating photosynthesis, ROS homeostasis, and cation flux kinetics in rice.

Understanding of cadmium (Cd) uptake mechanism and development of lower Cd crop genotypes are crucial for combating its phytotoxicity and meeting 70% increase in food demand by 2050. Bio-accumulation of Cd continuously challenges quality of life specifically in regions without adequate environmental planning. Here, we investigated the mechanisms operating in Cd tolerance of two rice genotypes (Heizhan-43 and Yinni-801). Damage to chlorophyll contents and PSII, histochemical staining and quantification of reactive oxygen species (ROS), cell viability and osmolyte accumulation were studied to decipher the interactions between Cd and zinc (Zn) by applying two Cd and two Zn levels (alone as well as combined). Cd2+ and Ca2+ fluxes were also measured by employing sole Cd100 (100 µmol L-1) and Zn50 (50 µmol L-1), and their combination with microelectrode ion flux estimation (MIFE) technique. Cd toxicity substantially reduced chlorophyll contents and maximal photochemical efficiency (Fv/Fm) compared to control plants. Zn supplementation reverted the Cd-induced toxicity by augmenting osmoprotectants and interfering with ROS homeostasis under combined treatments, particularly in Yinni-801 genotype. Fluorescence microscopy indicated a unique pattern of live and dead root cells, depicting more damage with Cd10, Cd15 and Cd15+Zn50. Our results confer that Cd2+ impairs the uptake of Ca2+ whereas, Zn not only competes with Cd2+ but also Ca2+, thereby modifying ion homeostasis in rice plants. This study suggests that exogenous application of Zn is beneficial for rice plants in ameliorating Cd toxicity in a genotype and dose dependent manner by minimizing ROS generation and suppressing collective oxidative damage. The observations confer that Yinni-801 performed better than Heizhan-43 genotype mainly under combined Zn treatments with low-Cd, presenting Zn fortification as a solution to increase rice production.

New insight into the impact of biochar during vermi-stabilization of divergent biowastes: Literature synthesis and research pursuits.

Biochar amendment for compost stabilization of divergent biowastes is gaining considerable attention due to environmental, agronomic and economic benefits. Research to date exhibits its favorable physico-chemical characteristics, viz. greater porosity, surface area, amount of functional groups, and cation exchange capacity (CEC), which allow interface with main nutrient cycles, favor microbial activities during composting, and improve the reproduction of earthworms during vermicomposting. Biochar amendment during composting and vermicomposting of biowastes boosts physico-chemical properties of compost mixture, microbial activities and organic matter degradation; and reduces nitrogen loss and emission of greenhouse gases (GHGs). It also improves the quality of final compost by increasing concentration of plant available nutrients, enhancing maturity, decreasing composting duration and reducing the toxicity of compost. Due to these characteristics, biochar could be considered a beneficial additive for the stabilization of different biowastes during composting and vermicomposting processes. Hence, good quality vermicompost, efficient recycling and management of biowastes could be achieved by addition of biochar through composting and vermicomposting.

Cadmium-zinc cross-talk delineates toxicity tolerance in rice via differential genes expression and physiological / ultrastructural adjustments.

Understanding the physiological and molecular response of crop genotypes could be useful in eco-toxicological evaluation with cadmium (Cd) and could be a strategy to solve heavy metal contamination in agriculture. This study corroborates unique patterns of Cd accumulation and molecular mechanisms adopted by plants to acquire Cd tolerance and counteractive effects of zinc (Zn) against Cd toxicity. Two rice (Oryza sativa) genotypes (Heizhan 43 and Yinni 801) differing in cadmium tolerance and its accumulation in plant tissues were investigated hydroponically using two Cd levels [Cd10 (10 µM L-1) and Cd15 (15 µM L-1)] and two Zn levels [Zn25 (25 µM L-2) and Zn50 (50 µM L-1)] and their combinations. Cadmium toxicity rendered substantial reduction in plant height, biomass, chlorophyll contents and photosynthesis as compared to the control plants after 15 days of treatment. Supplementation of Zn evidently ameliorated Cd toxicity by minimizing the reduction in plant growth, chlorophyll contents and photosynthetic attributes (Pn, gs, Ci, and Tr). Comparatively, lower accumulation of Cd in Yinni 801 under combined treatments revealed a preferential uptake of Zn in this genotype. A cross-talk among Cd, Zn, Fe, Ca and K correlated with fluctuating gs, Ci and Tr. Both genotypes also differed in morphological alterations of cell membrane, chloroplasts and appearance of enlarged plastoglobuli along with distorted mitochondria. An increased ascorbate peroxidase activity in roots of Yinni 801 presented a defensive strategy. Relative expression of Cd and Zn ion transporter genes also confirmed the genotypic background of phenotypic divergence. The OsLCT1 and OsHMA2 expression was significant in Heizhan 43, indicating possible translocation of Cd from shoot to grains contrary to Yinni 801, which accumulated Cd in shoot and showed stunted growth. Zn supplementation promises tolerance to Cd in Yinni 801 by differential expression of putative genes for Cd translocation with minimum ultrastructural modifications by maintaining physiological functions in contrast to Heizhan 43.

Exposure to nickel oxide nanoparticles insinuates physiological, ultrastructural and oxidative damage: A life cycle study on Eisenia fetida.

Although, health and environmental hazards of Ni are ironclad; however, that of Nickle oxide nanoparticles (NiO-NPs) are still obscure. Therefore, impact of NiO-NPs exposure (0, 5, 50, 200, 500 and 1000 mg kg-1 soil) on the earthworm (Eisenia fetida) survival (at 28th day), reproduction (at 56th day), histopathology, ultrastructures, antioxidant enzymes and oxidative DNA damage was appraised in full life cycle study. Lower concentrations of NiO-NPs (5, 50 and 200) did not influence the survival, reproduction and growth rate of adult worms significantly. However, reproduction reduced by 40-50% with 500 and 1000 mg kg-1 exposure, which also induced oxidative stress leading to DNA damage in earthworms. Ultrastructural observation and histology of earthworms exposed to higher NiO-NPs concentrations revealed abnormalities in epithelium layer, microvilli and mitochondria with underlying pathologies of epidermis and muscles, as well as adverse effects on the gut barrier. To the best of our knowledge, this is the first study unveiling the adverse effects of NiO-NPs on a soil invertebrate (Eisenia fetida). Our findings clue towards looking extensively into the risks of NiO-NPs on soil organisms bearing agricultural and environmental significance.

Functional and structural roles of wiry and sturdy rooted emerged macrophytes root functional traits in the abatement of nutrients and metals.

Macrophytes root functional traits (RFTs) play central roles in the cycling of aquatic contaminants, and there is evidence that emerged macrophytes differ in macronutrients (N and P) and heavy metals (Cd, Cr, Cu, Ni, Pb, V, Zn) abatement due to difference in RFTs. However, it remains ambiguous what root type of emerged macrophytes and their RFTs play more significant roles in the mineralization and removal of nutrients and heavy metals in aquatic systems. There is a clear need of intensive investigation on fibrous- and thick-root emerged macrophytes and their diverse RFTs in previous literatures to identify appropriate plants for phytoremediation technology. Morphological, physiological, anatomical, and symbiotic RFTs of fibrous-root emerged macrophytes favour the nutrients and heavy metals uptake. Thick-root emerged macrophytes with greater root rhizomes, lignifications and suberization illustrate tolerance under higher stress. Besides higher removal abilities of fibrous-root macrophytes, their limited lifespan and stress tolerance are the challenges for long-term removal of metals. Thus, it is still infancy to wrap up at once that the fibrous-root macrophytes and their RFTs are equally efficient for removal of heavy metals from aquatic ecosystems. Several advance techniques include cisgenesis intragenesis, symbiotic endophytes, and plant-harboring microbes are emerging to improve the RFTs of plants. These techniques need to be employed in emerged macrophytes to achieve desirable RFTs and targets. Still, these macrophytes require advanced studies on emerging contaminants, such as pharmaceutical and personal care products, organic carbon stability, and mitigation of greenhouse gases emission.

Eisenia fetida and biochar synergistically alleviate the heavy metals content during valorization of biosolids via enhancing vermicompost quality.

Impact of different biochars supplemented (10% w/w) to promote vermicomposting of sewage sludge (SS) and kitchen waste (KW) mixture (SS + KW, 70:30) was studied on the growth, reproduction and survival of earthworms, and ultimately the quality of vermicompost. Four types of biochar used as secondary material for preincubation (16 days) and vermicomposting (30 days) were: pine tree biochar (PTB), poplar plant biochar (PPB), wetland plant biochar (WPB) and yard waste biochar (YWB). Preincubation and vermicomposting of biomass mixture were undertaken in 60 L and 2 L capacity round-shaped bioreactors, respectively. Samples of biomass undergoing degradation were drawn after every 2 days during preincubation and with 5 days interval during vermicomposting to analyze them for plant nutrients and heavy metals contents. Amendment of vermicompost substrate (SS + KW) with biochars; PTB, PPB, WPB and YWB increased the reproduction rate of earthworms (Eisenia fetida) by 44.6, 53.9, 29.3 and 38.8%, respectively as compared to control (no biochar, NB). There has been significant reduction in total content of Cd (0.2-5.1%), Cr (7.3-10.8%), Cu (3.1-7.4%), Mn (3.2-8.4%), Pb (9.0-45.9%) and Zn (1.1-5.7%) by the application of different biochars as compared to NB after vermicomposting. The SEM/EDS images also reflected reduced concentration of these heavy metals in the final vermicompost as compared to initial mixtures. Progressively, biochar amendments increased the concentration of all macronutrients, viz., TN (15.8-31.0%), TP (8.6-9.9%), TK (2.8-17.3%), Ca (4.1-9.9%) and Mg (0.8-12.2%); while, reduced the pH (1.9-2.3%), content of Na (6.6-22.3%), TOC (6.6-15.4%), OM (5.0-8.2%) and C:N ratio (2.6-18.9%). Earthworm body accumulation factor (BAF) of heavy metals was: Cd > Zn > Pb > Cu > Mn > Cr at the termination stage of experiment. In conclusion, amending the SS + KW mixture with 10% (w/w) PPB for vermicomposting rendered higher count of cocoons, growth rate and reproduction rate of earthworms, which ultimately produce nutrients-rich vermicompost lower in heavy metals.

Preincubation and vermicomposting of divergent biosolids exhibit vice versa multielements stoichiometry and earthworm physiology.

Sewage sludge and kitchen refuse are ubiquitously mounting wastes with high organic load, which if reprocessed they could salvage the environment. Reckoned with this certitude, an incubating study was initiated on sequential preincubation of sewage sludge with kitchen waste in 100:0, 70:30, 50:50, and 30:70 ratios for 16 days ensued by vermicomposting of 30 days using Eisenia fetida. Concentration of heavy metals (Cd, Cr, Cu, Mn, Pb, and Zn) in the biosolid mixtures increased during preincubation but reduced progressively through vermicomposting due to bioaccumulation of these metals in the earthworm tissues. Earthworm growth parameters data reflected that sewage sludge and kitchen waste mixture with 70:30 ratio increased the number of cocoons (10.6%), biomass (8.2%), growth rate (8.3%), reproduction rate (12.2%), and decreased their mean mortality rate (80.1%) as compared to that in sole sewage sludge (control). Results of chemical analysis and SEM/EDS imaging, showed that alkalinity, organic carbon, C/N ratio, organic matter and concentration of trace elements (Cd, Cr, Cu, Mn, Pb, and Zn) reduced while macronutrients (N, P, K, Ca and Mg) increased in the final vermicompost as compared to that in initial mixtures. The FT-IR analysis also revealed that various biochemical functional groups underwent biodegradation during combined preincubation-vermicomposting. Bioaccumulation factor (BAF) of all trace elements in the earthworm tissues was higher with 70:30 ratio of substrates, with the trend of Cd > Zn > Cu > Mn > Pb > Cr. Hence, this study concludes that combined preincubation-vermicomposting is the most efficient and ecofriendly technique for biodegradation, stabilization, and conversion of sewage sludge and kitchen waste into organic fertilizer. The nutrient rich vermicompost can be safely used as horticultural substrate and soil conditioner for efficient management of degraded soils. Finally, combined preincubation-vermicomposting is a sustainable system of recycling the sewage sludge along with kitchen waste.

Comparison of floating-bed wetland and gravel filter amended with limestone and sawdust for sewage treatment.

Advancements in the design and technology of constructed wetlands for efficient removal of wastewater contaminants are ever in progress to develop situation-based economical systems. Here, we entrenched two horizontal sub-surface flow constructed wetlands (HSFCW) with either chemical, viz. limestone (HSFCW-LS) or organic, viz. sawdust (HSFCW-SD) substrates, and compared them with biological method, viz. growing of water spinach in floating-bed-constructed wetland (FBCW-WS) to enhance the performance of CWs. Same sewage wastewater was used as influent in each fortified CW replicated thrice. Sewage was replaced weekly, for a total of 12 weeks of experimentation. Sampling of raw sewage from influent was undertaken at the inlet in the beginning, and that of treated effluent from the outlet after a week of treatments. Quality of raw sewage used weekly during experimentation remained almost uniform and near to the wastewater standards. Cumulative data of treated wastewater depicted that the FBCW-WS achieved the highest performance in the removal of total nitrogen (TN), [Formula: see text]-N, and total phosphorus (TP) with average removal efficiencies of 75.9, 90.5, and 94.3%, respectively. Whereas, HSFCW-SD performed better for [Formula: see text]-N, FC, and TSS with corresponding removal efficiency of 77.5, 64.3, and 74.2% while HSFCW-LS showed average performance. This study concludes that performance of biological method of macrophyte cultivation (FBCW-WS) is significantly superior to chemical and organic substrates, so it could be more effective, economical, and sustainable approach for sewage treatment.

Cryptic footprints of rare earth elements on natural resources and living organisms.

BACKGROUND: Rare earth elements (REEs) are gaining attention due to rapid rise of modern industries and technological developments in their usage and residual fingerprinting. Cryptic entry of REEs in the natural resources and environment is significant; therefore, life on earth is prone to their nasty effects. Scientific sectors have expressed concerns over the entry of REEs into food chains, which ultimately influences their intake and metabolism in the living organisms. OBJECTIVES: Extensive scientific collections and intensive look in to the latest explorations agglomerated in this document aim to depict the distribution of REEs in soil, sediments, surface waters and groundwater possibly around the globe. Furthermore, it draws attention towards potential risks of intensive industrialization and modern agriculture to the exposure of REEs, and their effects on living organisms. It also draws links of REEs usage and their footprints in natural resources with the major food chains involving plants, animals and humans. METHODS: Scientific literature preferably spanning over the last five years was obtained online from the MEDLINE and other sources publishing the latest studies on REEs distribution, properties, usage, cycling and intrusion in the environment and food-chains. Distribution of REEs in agricultural soils, sediments, surface and ground water was drawn on the global map, together with transport pathways of REEs and their cycling in the natural resources. RESULTS: Fourteen REEs (Ce, Dy, Er, Eu, Gd, Ho, La, Lu, Nd, Pr, Sm, Tb, Th and Yb) were plighted in this study. Wide range of their concentrations has been detected in agricultural soils (<15.9-249.1 µg g-1) and in groundwater (<3.1-146.2 µg L-1) at various sites worldwide. They have strong tendency to accumulate in the human body, and thus associated with kidney stones. The REEs could also perturb the animal physiology, especially affecting the reproductive development in both terrestrial and aquatic animals. In plants, REEs might affect the germination, root and shoot development and flowering at concentration ranging from 0.4 to 150 mg kg-1. CONCLUSIONS: This review article precisely narrates the current status, sources, and potential effects of REEs on plants, animals, humans health. There are also a few examples where REEs have been used to benefit human health. However, still there is scarce information about threshold levels of REEs in the soil, aquatic, and terrestrial resources as well as living entities. Therefore, an aggressive effort is required for global action to generate more data on REEs. This implies we prescribe an urgent need for inter-disciplinary studies about REEs in order to identify their toxic effects on both ecosystems and organisms.

Whole-Genome Resequencing of a Worldwide Collection of Rapeseed Accessions Reveals the Genetic Basis of Ecotype Divergence.

Rapeseed (Brassica napus), an important oilseed crop, has adapted to diverse climate zones and latitudes by forming three main ecotype groups, namely winter, semi-winter, and spring types. However, genetic variations underlying the divergence of these ecotypes are largely unknown. Here, we report the global pattern of genetic polymorphisms in rapeseed determined by resequencing a worldwide collection of 991 germplasm accessions. A total of 5.56 and 5.53 million single-nucleotide polymorphisms (SNPs) as well as 1.86 and 1.92 million InDels were identified by mapping reads to the reference genomes of "Darmor-bzh" and "Tapidor," respectively. We generated a map of allelic drift paths that shows splits and mixtures of the main populations, and revealed an asymmetric evolution of the two subgenomes of B. napus by calculating the genetic diversity and linkage disequilibrium parameters. Selective-sweep analysis revealed genetic changes in genes orthologous to those regulating various aspects of plant development and response to stresses. A genome-wide association study identified SNPs in the promoter regions of FLOWERING LOCUS T and FLOWERING LOCUS C orthologs that corresponded to the different rapeseed ecotype groups. Our study provides important insights into the genomic footprints of rapeseed evolution and flowering-time divergence among three ecotype groups, and will facilitate screening of molecular markers for accelerating rapeseed breeding.

Respiring cellular nano-magnets.

Magnetotactic bacteria provide an interesting example for the biosynthesis of magnetic (Fe3O4 or Fe3S4) nanoparticles, synthesized through a process known as biologically controlled mineralization, resulting in complex monodispersed, and nanostructures with unique magnetic properties. In this work, we report a novel aerobic bacterial strain isolated from sludge of an oil refinery. Microscopic and staining analysis revealed that it was a gram positive rod with the capability to thrive in a medium (9K) supplemented, with Fe2+ ions at an acidic pH (~3.2). The magnetic behaviour of these cells was tested by their alignment towards a permanent magnet, and later on confirmed by magnetometry analysis. The X-ray diffraction studies proved the cellular biosynthesis of magnetite nanoparticles inside the bacteria. This novel, bio-nano-magnet, could pave the way for green synthesis of magnetic nanoparticles to be used in industrial and medical applications such as MRI, magnetic hyperthermia and ferrofluids.