Cadmium (Cd) contamination poses a significant threat to global agricultural production and hyperaccumulating plant species, such as Solanum nigrum (L.), face challenges in phytoremediation due to limited biomass production. Application of plant growth regulators such as, folic acid (FA) is a promising strategy to increase biomass production in these plant species. Therefore, a study was conducted to assess the interaction between FA and Cd in the mining ecotype of S. nigrum. The study involved two phases: germination and growth. In the first phase, seeds were exposed to different concentrations of CdCl2 (i.e. 0, 10, 25, 50, 100, 200, and 400 µM) in the presence (0, 25, 50 and 100 µM) or absence of FA for ten days. Results showed that FA enhanced seed germination under Cd stress and acted as an antioxidant and stimulated germination and emergence at moderate concentrations. At higher concentrations, it reduced germination percentage. The study also found significant variations (P <0.05) in growth attributes and Cd uptake in all FA concentrations. Cd was generally higher in shoots than roots, with the highest Cd concentration found in T6 (200 µmol Cd + 50 µmol/L FA) with a 170-fold difference (mean value: 1690 mg/kg) from control (10 mg/kg). Furthermore, an increase in exposure time led to a 2-fold increase in reduced glutathione (GSH) level in leaves at T3 (100 µmol/L Cd + 50 µmol/L FA).Therefore, we concluded that FA is a biostimulant that activates protective mechanism, alleviates oxidative stress and improves Cd uptake and accumulation in hyper-accumulating species.

The phytohormones cytokinins (CKs) are known to regulate apical/auxiliary meristems, control shoot growth and are associated with nutrient uptake and high biomass production. In this study, different cytokinins were tested on Sedum alfredii (S.alfredii) for shoot proliferation and growth performance as well as their correlation with phytoextraction efficiency. Among the tested cytokinins, Zeatin (ZTN) treatments produced the highest number of shoots (5-6 per explant) with 5 and 10 μM ZTN concentrations which are shown as zeatin (ZTN) > kinetin (KTN) > benzylaminopurine (BA) > thidiazuron (TDZ). Maximum biomass production was produced on these media. The maximum biomass (0.14 g) was found in 10 μM ZTN concentration with a 1-fold difference (mean value: 0.02 g) from CK (0.12 g). However, the lowest biomass (0.11 g) was found with 4 μM TDZ, with a 1-fold difference (mean value: 0.02 g) from CK (0.13 g) which suppressed shoot growth. The leaf area and leaf chlorophyll index were significantly increased in all cytokinins except TDZ, and the relation was ZTN > KTN > BA>CK > TDZ. Cadmium accumulation was significantly higher in treatments containing cytokinins as compared to cytokinin-free media. Zeatin at 10 μM concentration was the most effective for high biomass production and correlated with higher cadmium uptake efficiency. The results suggest that cytokinins particularly ZTN, play a crucial role in enhancing both biomass production and cadmium, uptake efficiency in S. alfredii. Therefore, in large-scale phytoremediation initiatives conducted in field conditions, cytokinins can be utilized as growth regulators to enhance biomass production and cadmium extraction efficiency in S.alfredii.

Heavy metal pollution in metropolitan soils poses significant risks to human health and the entire ecosystem. Effective mitigation strategies and technologies are crucial for addressing these environmental issues. Fast-growing trees are an essential part of phytoremediation projects all over the world and provide long-term ecological benefits to mankind. This study assessed the lead tolerance and phytoremediation potential of a fast-growing soapberry tree species (Sapindus mukorossi) in moderately contaminated soil. Two independent experiments were conducted to assess its tolerance at (i) germination level and (ii) prolonged growth stage. In the germination experiments, seeds were exposed to lead (II) nitrate Pb (NO₃)₂ at various concentrations (0, 5, 10, 20, 50, 100, 200, 300, 400 and 500 μM) for 120 days. Results showed significant differences in germination time, germination index, seedling vigor index, energy of germination, final germination, germination inhibition, seedling height and root/shoot weight compared to the control experiments. In the prolonged growth experiments, seedlings were grown for six months in soils amended/spiked with different Pb concentrations (T0 = 0, T1 = 20, T2 = 50, T3 = 100, T4 = 150 and T5 = 200 mg kg−1 soil) and their biomass was determined. The highest biomass achieved in six months (T0: 12.62 g plant−1), followed by (T1: 12.33 g plant−1), (T2: 12.42 g plant−1), (T3: 11.86 g plant−1), (T4: 10.86 g plant−1) and (T5: 10.06 g plant−1) respectively. S. mukorossi showed no visible signs of Pb toxicity over a six-month period. During six months of exposure, the total Pb content in S. mucrossi tissues were classified as roots > leaves > stems. The highest cumulative absorption of Pb occurred between the fourth and fifth months of exposure. Maximum transfer factor (TF) was detected during the fourth month ranging from 0.888 to 1.012 for the different Pb concentrations. Furthermore, the growth behavior, lead accumulation, bioconcentration factors (BCF) and tolerance index (TI) indicated that S. mucrossi may tolerate moderate Pb concentrations for longer periods. These findings suggest that S. mukorossi may be deployed for long-term phytoremediation coupled with urban forest applications in the future.

In this study, Rhizobium rhizogenes-mediated root proliferation system in Sedum alfredii has been established. Twenty strains of R. rhizogenes were screened for root proliferation. A significant difference (P < 0.01) was observed in plant morphological characters under influence of different bacterial strains. The highest root fresh weight (3.236 g/plant) was observed with strain AS12556. Furthermore, significant difference (P < 0.05) was observed in the chemical composition of organic acids, Tartaric acid (TA), Succinic acid (SA), Malic acid (MA), Citric acid (CA) and Oxalic acid (OA), pH, Total Nitrogen (TN), Total Organic Carbon (TOC) and soluble sugars in root exudates with different R. rhizogenes mediated roots. Furthermore, a series of hydroponics experiments were conducted with varying concentrations of Cd (25, 50 and 75 µM) and Zn (100, 200 and 500 µM) to assess the phytoextraction efficiency of proliferated roots with Rhizobium. Several plants with proliferated roots showed enhanced growth and improved metal extraction efficiency. Five strains (LBA 9402, K599, AS12556, MSU440 and C58C1) were identified as potential strains for root proliferation in Sedum alfredii. R. rhizogenes strain AS12556 improved Cd/Zn phytoextraction by exogenous production of phytochemicals to promote root proliferation, improved shoot biomass, lowered oxidative damage and enhanced phytoextraction efficiency in S. alfredii. Therefore, it has been selected as a potential microbial partner of S. alfredii to develop extensive rooting system for better growth and enhanced phytoremediation potential. Results suggest that R. rhizogenes mediated root proliferation system can be used for optimizing metal extraction from contaminated soils.

The genetic structure of salt-tolerant halophytic grass Sporobolus ioclados collected from inland and coastal areas of Pakistan was determined using P450 based analog (PBA); the functional genomic markers. Our data revealed high polymorphism (96%) in the collected germplasm. The high genetic variability could be attributed to outcrossing, and sexual reproduction. An analysis of molecular variance depicted higher genetic diversity (80%) within the populations and lower (20%) among the populations. The low genetic diversity among the inland and coastal populations might be due to fragmentation and long physical distances. The dendrogram and principal component analysis clearly distinguished the genotypes of the two populations into two distinct clusters. Our data demonstrated that PBA markers are reliable and reproducible for assessing genetic diversity in halophytic grass and provides valuable insight for future breeding and conservation programs.

Thirty-seven accessions of oilseed sunflower were evaluated under natural field conditions for growth performance, ligno-cellulosic mass production of bioenergy, and metal uptake potential during the remediation of arsenic and mercury-contaminated soil. Significant variations were observed in the lignocellulosic components of plant stems at maturity, decreasing the following order: total sugars > cellulose > hemicellulose > lignin > ash. A significant difference was also noted in metal uptake among the different accessions. The highest concentrations in the above-ground parts were 14.08 and 0.40 mg/kg, respectively for As and Hg. In rhizosphere soil concentrations of inorganic As species (arsenate: 69.73 mg/kg, arsenite: 4.41 mg/kg) were higher, as compared organic As (dimethyl arsenic: 0.22 mg/kg); mono-methyl arsenic: 0.02 mg/kg). Arsenate concentration (3.72 mg/kg) was higher in root, whereas arsenite concentration (0.47 mg/kg) was higher in the shoots. Many accessions showed good oil production (26e45.6%), with the highest percentage of oleic (75%) and linoleic acids (37.6%). These results suggest that some oilseed sunflower cultivars could be adopted as crop plants for effective remediation of lightly to moderately As-/Hg-contaminated soils, coupled with agro-production. (c) 2020 Elsevier Ltd. All rights reserved.

The effects of Sedum alfredii monoculture, intercropping of S. alfredii and oilseed rape, and rotation of S. alfredii and sunflower on cadmium (Cd) and lead (Pb) remediation efficiency in field conditions were compared by combining organic materials and specific endophyte. After one round of remediation, the results showed that the extraction amount of Cd and Pb was the highest under the S. alfredii and sunflower rotation intensified remediation mode. Under the remediation mode, 394.8 g/hm2 Cd and 110.2 g/hm2 Pb were extracted from the contaminated soils, which were 3.1%-101.0% and 22.0%-139.0% higher than the other treatments, respectively. Moreover, the contents of total Cd and available Cd in the contaminated soils decreased by 26.6% and 31.1%, respectively; the contents of total Pb and available Pb in the contaminated soils decreased by 4.3% and 20.9%, respectively. Considering the factors such as mechanized farming, rotation of S. alfredii and sunflower is easy to operate and more suitable for practical field application.

Phytoremediation is a valuable technology for mitigating soil contamination in agricultural lands, but phytoremediation without economic revenue is unfeasible for land owners and farmers. The use of crops with high biomass and bioenergy for phytoremediation is a unique strategy to derive supplementary benefits along with remediation activities. Sunflower (Helianthus annuus L.) is a high-biomass crop that can be used for the phytoremediation of polluted lands with additional advantages (biomass and oil). In this study, 40 germplasms of sunflower were screened in field conditions for phytoremediation with the possibility for oil and meal production. The study was carried out to the physiological maturity stage. All studied germplasms mopped up substantial concentrations of Pb, with maximum amounts in shoot > root > seed respectively. The phytoextraction efficiency of the germplasm was assessed in terms of the Transfer factor (TF), Metal removal efficiency (MRE) and Metal extraction ratio (MER). Among all assessed criteria, GP.8585 was found to be most appropriate for restoring moderately Pb-contaminated soil accompanied with providing high biomass and high yield production. The Pb content in the oil of GP.8585 was below the Food safety standard of China, with 59.5% oleic acid and 32.1% linoleic acid. Moreover, amino acid analysis in meal illustrated significant differences among essential and non-essential amino acids. Glutamic acid was found in the highest percentage (22.4%), whereas cysteine in the lowest percentage (1.3%). Therefore, its efficient phytoextraction ability and good quality edible oil and meal production makes GP.8585 the most convenient sunflower germplasm for phytoremediation of moderately Pb-contaminated soil, with fringe benefits to farmers and landowners.

Phytoremediation coupled with agro-production is a sustainable strategy for remediation of toxic metal contaminated farmlands without interrupting crop production. In this study, high accumulating oilseed rape was rotated with low accumulating rice to evaluate the effects of crop rotation on growth performance and uptake of cadmium (Cd) in plants. In this system, oilseed rape was inoculated with plant growth promoting endophyte (PGPE) consortium, and rice was applied with soil composite amendment and foliar inhibitor. The results showed, compared with rice monoculture, crop rotation coupled with superposition measure has potential to enhance yield, biomass and nutritional quality of both crops, as well as to increase Cd uptake in non-edible tissues of oilseed rape and to reduce Cd concentration in individual parts of rice, thus accelerating phytoextraction and ensuring food safety. These comprehensive management practices removed 7.03 and 7.91% total Cd from two experiment fields, respectively, in three years phytoremediation. These results demonstrated a feasible technical mode for phytoremediation coupled with argo-production in slightly Cd contaminated field, and also provided useful information for further investigation of interaction mechanisms between the rotated crops and biofortification measures.

The present study investigated the effects of foliar application of zinc (Zn) and selenium (Se) on bioavailability of Zn and Se and toxicity of cadmium (Cd) and lead (Pb) to different water spinach ecotypes (LA and HA) grown in slightly (XZ) or moderately (LJY) contaminated fields via in vitro digestion combined with Caco-2/HL-7702 cell model. The obtained results revealed that foliar application of Zn and Se promoted yield, increased total, bioaccessible and bioavailable fractions of Zn and Se in plants, indicating that foliar application is a feasible way of biofortification. Although there was no significant effect on liver cell proliferation (MTT), membrane stability (LDH) and hepatocyte enzyme (ALT and AST) activities, the obvious ecotype and soil dependent fluctuations of lipid peroxidation (MDA) and antioxidant enzyme (SOD, POD and CAT) activities in serum highly suggest that the low accumulator and clean field should be used in agricultural production rather than the high accumulator and contaminated farmland. Moreover, foliar application of Zn and Se improved nutritional quality of all water spinach genotypes in both fields, including increased Fe, vitamin C, cellulose and chlorophyll, maintained concentrations of potassium (K), manganese (Mn), copper (Cu), protein, and nitrate. These results demonstrate that this agricultural management practice may prove to be an effective approach for minimizing health risk and alleviating "hidden hunger" in the developing countries.

Phytoremediation coupled with agro-production is considered a sustainable strategy for remediation of trace element contaminated fields without interrupting crop production. In this study hyperaccumulator Sedum alfredii was intercropped with a leguminous plant fava bean (Vicia fava) in cadmium (Cd) and lead (Pb) co-contaminated field to evaluate the effects of intercropping on growth performance and accumulations of trace elements in plants with plant growth promoting endophyte (PGPE) consortium application. The results showed, compared with monoculture, intercropping coupled with inoculation application promoted biomass as well as Cd and Pb concentrations in individual parts of both plants, thus increasing the removal efficiencies of trace elements (4.49-folds for Cd and 5.41-folds for Pb). Meanwhile, this superposition biofortification measure maintained normal yield and nutrient content, and limited the concentration of Cd and Pb within the permissible limit (<0.2 mg kg-1 FW) in fava bean during the grain production. These results demonstrated a feasible technical system for phytoremediation coupled with agro-production in slightly or moderately Cd and Pb co-contaminated field, and also provided useful information for further investigation of interaction mechanisms between intercropping and PGPEs inoculation.

Information is needed for comparative assessment and agronomic practices for phytoavoidation in multi-pollutant field. A field study was conducted to explore 97Brassica pekinensisL. genotypes with permissible limit of contaminants growing in a severely Cd, moderately nitrate and slightly Pb multi-polluted field. Thirteen genotypes, i.e.KGZY,CXQW,CAIB,JINL,JQIN,JFEN,WMQF,XLSH,TAIK,BJXS,JUKA,XYJQandGQBW, were identified with permissible limit for nitrate, Cd and Pb based on their resistance to heavy metal and nitrate accumulation in leaves when grown in co-contaminated soils. Furthermore, the correlation between essential and toxic elements concentrations in plant ofB. pekinensiswere inconsistent. Generally speaking, application of increasing Ca, K and S fertilizers in appropriate forms and dosages tended to increase the yield and quality ofB. pekinensiscultivated in multi-pollutant field.

Availability of cadmium (Cd) and nitrate and their transfer to green leafy vegetables is highly dependent on physical, chemical and biochemical conditions of the soil. The phenotypic characteristics, accumulation of hazardous materials and rhizosphere properties of two ecotypes of water spinach in response to water stress were investigated. Flooding significantly enhanced plant growth and decreased Cd and nitrate concentrations in the shoot and root of both ecotypes of water spinach. Flooding extensively changed the physicochemical properties and biological processes in the rhizosphere, including increased pH and activities of urease and acid phosphatase, and decreased availability of Cd and nitrate and activity of nitrate reductase. Furthermore, flooding increased rhizosphere bacteria community diversity (including richness and evenness) and changed their community structure. Denitrifying bacteria (Clostridiales, Azoarcus and Pseudomonas), toxic metal resistant microorganisms (Rhodosporillaceae, Rhizobiales and Geobacter) were enriched in the rhizosphere under flooding conditions, and the plant growth-promoting taxa (Sphingomonadaceae) were preferentially colonized in the high accumulator (HA) rhizosphere region. These results indicated that flooding treatments result in biochemical and microbiological changes in soil, especially in the rhizosphere and reduced the availability of Cd and nitrate to plants, thus decreasing their uptake by water spinach. It is, therefore, possible to promote crop growth and reduce the accumulation of hazardous materials in vegetable crops like water spinach by controlling soil moisture conditions.

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.

The identification of high yield genotypes that are capable of accumulating multiple heavy metals in the non-edible parts (roots and shoots), but not in the edible parts (seeds) and have desired nutritional value is necessary for accomplishing phytoremediation coupled with agro-production. In this study, 17 fava bean genotypes were screened in two different field conditions to examine their phytoremediation potential in terms of uptake and translocation of Cd and Pb. Ten genotypes, LBAO, JNJX, DCAN, QXCJ, QIKM, LXYC, YDL6, RBCD, QPID and ZHW6 were found as the best accumulators for Cd and Pb with permissible limit of metals in seeds. The concentration of plant nutrients were genotype and soil type dependent and there was a significant correlation between these two factors. Furthermore, the three genotypes DCAN, LBAO and LXYC showed best performance in alluvial soil type while QPID, RBCD and LXYC were the best in red soil type. Genotype LXYC was similar for both soil types and appeared to be the best fit for phytoremediation coupled with agro-production for slightly or moderately Cd and Pb co-contaminated soil. Therefore, fava bean LXYC genotype is suggested as a potential candidate for phytoremediation of Cd/Pb co-contaminated soils coupled with agro-production.

Rapid industrialization in China accelerated environmental pollution by xenophores and trace metals particularly cadmium. Numerous studies have been conducted to address soil contamination using organic and inorganic amendments under pot or incubation conditions, but few were performed under field conditions, particularly in the wheat-growing areas. This study aims to investigate the effectiveness of pre-applied soil amendments for Cd immobilization, changes in soil pH, and metal uptake by wheat. In this study, 12 treatments, i.e., control (CK), lime, DaSan Yuan (DASY), DiKang No. 1 (DEK1), biochar, Fe-biochar, Yirang, CaMgP, and green stabilizing agents (GSA-1, GSA-2, GSA-3, and GSA-4), were evaluated for Cd immobilization in incubation and field experiments. Changes in soil pH and available metal content with amendments were monitored from 30 to 150 days of incubation. Single extraction method and DTPA-extractable and sequential extraction procedures were employed to assess the variations in available Cd contents of field soil. The impact of soil amendments on Cd uptake and bioaccumulation in food part of wheat was measured at harvesting stage in a contaminated site. Lime treatment increased soil pH by 32% and reduced available Cd to 0.213 mg kg−1, as compared to CK (control) in the incubation experiment (0.343 mg kg−1). Effects of the amendments on wheat growth, soil pH, and Cd phytoavailability were reported. Wheat biomass was highest in treatment GSA-2 (13,880 kg ha−1) and GAS-4 resulted in an increase in grain yield (5350 kg ha−1). Soil pH of the treated field at harvesting stage increased up to 6.50, 6.50, and 6.47 by application of GSA-4, GSA-2, and lime, respectively. Cadmium contents in wheat grain were declined significantly in the treatments of GSA-2, GSA-4, and lime. Results of this study revealed a significant decrease in available Cd concentration with the application of amendments. Composite amendments were more effective in terms of metal uptake and bioaccumulation in wheat. In addition, our results indicate the effectiveness of composite amendments in stabilizing Cd in contaminated soil.

Quantitative phenotypic traits of pseudocarps and seeds of Chimonanthus praecox (L.) Link. are described from a road-side tree in Chengdu, Sichuan province of China. The parameters included 1. Air dried pseudocarp weight (PW), 2. Seed Yield per pseudocarp (SYP), 3. Number of seeds per pseudocarp (NSP, the brood size), 4. weight of Empty pseudocarp (WEP), 5. Mean single seed weight (MSSW) in each of 131pseudocarps, 6. Seed weight variation and distribution in a composite sample of 468 seeds, 7. Seed packaging cost per seed (SPC1 = WEP / NSP and seed packaging cost per g seeds (SPC2 = WEP / SYP). The phenotypic traits of seeds and pseudocarps were rich in variation and exhibited great deal of co-linearity amongst them. The pseudocarp weight (PW) averaged to 1.4726 ± 0.047g and seed wt. averaged to 0.2455 ± 0.002688 g. The weights of pseudocarps and seeds were found to vary by 39.96 and 23.73%, respectively. Around 16% pseudocarps had weight ≤ 1.0g, and those in the size class of 1.01 to 2.0g were 65.7% in number. Seed packaging cost per seed (SPC1) was 0.1417 ± 0.00566g and on the basis of one g seeds (SPC2), 0.5933 ± 0.02826g. SPC1 and SPC2 varied by 47.75 and 54.52%, respectively. The results are compared and discussed on the basis of available literature.

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 (32-8.4%), 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 (0.8-122%); while, reduced the pH (1.9-2.3%), content of Na (6.6-22.3%), TOC (6.6-15.4%), OM (5.0-82%) 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. (C) 2019 Elsevier B.V. All rights reserved.

Forty oilseed sunflower cultivars were screened in two soil types for phytoremediation of Cd coupled with maximum biomass yield and oil production. Several cultivars exhibited a significant difference in biomass and yield with enhanced uptake in shoots and low accumulation in roots from two Cd-contaminated soil types, an Oxisol and an Iceptisol. The Transfer Factor of Cd was >1 in several cultivars in both soil types, where as a significant difference in phytoextraction of Cd was observed in the Oxisol (acidic soil), greater than in the Inceptisol (alkaline soil). The results revealed that of the 40 cultivars, S9178, Huanong 667in the Oxisol and cvs. DW 667, HN 667, Huanong 667 and 668F1 in the Inceptisol showed a high biomass, better yield and enhanced accumulation of Cd in the shoots but a lesser accumulation in oil. The screened cultivar S 9178 produced the greatest amount of oil (55.6%) with 77% oleic acid, which makes it suitable for human consumption. Cultivar Huanong 667 was found to be the highest accumulating cultivar in both soil types. It is therefore suggested that some sunflower cultivars do exhibit phytoremediation potential together with agro-production potential.

Field experiments were conducted in two consecutive rice-wheat cropping seasons on a yellow clay soil to assess the efficacy of organic and inorganic amendments for cadmium (Cd) and lead (Pb) immobilization. Amendments were applied alone and in combinations to compare their efficacy for metals immobilization. Composite amendment of GSA-4 (Green Stabilizing Agent) and biochar resulted in higher biomass and grains yield for both rice (Oryza sativa L.) and wheat (Triticum aestivum L.). Liming, DEK1 (Di Kang No. 1) or GSA-4 amendment increased soil pH from 6.34 to 7.35, 7.20 and 7.15, respectively. Soil amendments significantly reduced DTPA extractable Cd and Pb in soil at wheat harvest. Cadmium and Pb fractionation showed a significant decrease in the extractable fractions by the amendment of biochar (34% and 25%) or GSA-4 (35% and 26%, respectively). GSA-4 and biochar amendment enhanced metals immobilization and reduced their uptake by plant and subsequent accumulation in the grains of rice and wheat, particularly with GSA-4. These results indicate that GSA-4 and biochar, especially their combination, have great potential for application to remediate Cd and Pb contaminated soils.