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This study examined the effects of straw from cadmium (Cd)-accumulator plant species on the growth and Cd uptake of Ziziphus acidojujuba seedlings grown in Cd-containing soil. The treatments were independent applications of straw from seven Cd-accumulator plant species (Cardamine hirsuta, Gnaphalium polycaulon, Pterocypsela laciniata, Malachium aquaticum, Galium aparine, Conyza canadensis, and Stellaria media) and a no-straw control. The whole-plant biomass, total chlorophyll and soluble sugar contents, and antioxidant enzymes activities in Z. acidojujuba seedlings under the different straw treatments showed the following trend: P. laciniata > M. aquaticum > S. media > C. canadensis > G. polycaulon > control > G. aparine > C. hirsuta. Compared with the control, the Cd contents in roots of Z. acidojujuba seedlings after any straw application significantly decreased by 19.05%-43.76%, and the Cd contents in shoots decreased by 31.58%-54.39%, except after G. aparine, G. polycaulon, and C. hirsuta straws applications. Therefore, the application of P. laciniata, M. aquaticum, and S. media straws promoted the growth and reduced the Cd uptake of Z. acidojujuba seedlings most significantly, making them ideal remediation materials for Cd-contaminated jujuba orchards. [ABSTRACT FROM AUTHOR]

The study aims to reveal the effects of different Zn levels on pot marigold. We determined some germination and young seedling properties in the first experiment, and morphological, stomatal, and physiological parameters besides uptake profiles of both Zn and other plant nutrients in the second one. We supplied the water requirement of the seeds with Zn solutions (0, 250, 500, 750, and 1,000 mg l−1) in the first experiment, and We added the same zinc doses as mg kg−1 to the soil of the pots where the plants would grow in the second one. As a result, the inhibitory effects were more prominent in the early seedling stage (especially at 1,000 mg l−1 Zn) than in the germination one. We determined plant growth retardation, decreases in leaf water contents, and increases in membrane damages with higher Zn (≥500 mg kg−1) in the experiment conducted by potting soil. We detected decreases in chlorophyll parameters parallel with the increases in Zn. The alterations in plant zinc contents revealed the accumulation capacity of pot marigold in potting conditions. That TF value >1 in Zn treatments up to 500 mg kg−1 points to the efficiency limit of pot marigold as a Zn-accumulator plant. To reveal the zinc tolerance of the plant through experiments carried out in two different plant growth stages, germination-young seedling and adult plant is an innovative approach. Besides, it is the first study to evaluate detailed morphological, physiological, stomatal and nutrient contents of pot marigold under heavy metal stress conditions. Thus, this study displayed both tolerance level and accumulation potential in potting conditions of pot-marigold to zinc. [ABSTRACT FROM AUTHOR]

Soils with high lead (Pb) levels can be decontaminated with the use of tolerant plants. Their effectiveness may be increased with added soil N due to boosted plant vigor, but such an agronomic practice has not been widely reported so far. In this work, purslane (Portulaca oleracea) was tested in a pot experiment as a potential phytoremediation species using soil spiked with Pb at doses of 0, 150, 300, 600, and 900 mg kg−1 (referred to as Pb(0), Pb(150), Pb(300), Pb(600), and Pb(900), respectively) with added N (referred to as N(1); at 300 kg N ha−1) and without added N (N(0)). We found that added Pb did not cause any adverse effects on plant growth (height, and aerial and root dry biomass) and physiological parameters, which were boosted with added N. Lead plant concentration and uptake significantly increased with added N, a finding that confirms our hypothesis. The number of necessary harvests of purslane in order to reduce soil Pb to half its initial concentration was also calculated and found to decrease with added N, being 131 at Pb(900)N(1). Although results indicate the potential of purslane as a phytoremediation species, further research is needed under real field conditions. [ABSTRACT FROM AUTHOR]

In order to assess the heavy metal pollution of soils and crops around a typical manganese mine tailing in North Guangxi, and to select suitable plant materials for the remediation of heavy metal pollution in this area, nine crop samples, 23 dominant plant species and their rhizosphere soils, were collected. The contents of Cd, Mn, Cr, Pb and Zn of the samples were analyzed. The ecological risks of heavy metals in the soils and crops were evaluated using the single factor and comprehensive pollution index. The bioconcentration and translocation factors of the dominant plant species were calculated. The results were as follows:(1)Cd and Mn were the dominant pollutants in the soils of the studied area. The values of single factor pollution index of Cd and Mn reached 18.53 and 147.09 respectively. (2)The contents of Cd, Cr and Pb in crops such as Arachis hypogaea and Brassica chinensis exceeded the threshold values in the National Food Safety Standards(GB 2762—2017), which had great health risks.(3)Among the 23 dominant plant species, thetranslocation factors of Celosia argentea, Bidens pilosa, Emilia sonchifolia and Eremochloa ciliaris for several heavy metals were greater than one, indicating that they have the characteristics of metal accumulating plants. The heavy metal contents in roots of Arisaema erubescens, Ricinus communis, and Senecio scandens were relatively higher, while their translocation factors were relatively lower, indicating that they were root hoarding plant. The metal contents in the shoots and roots of Crotalaria albida, Rottboellia exaltata and Sonchus arvensis were relatively lower, while they kept healthy in the contaminated soil, indicating that they were elusive plants. The results show that the soils in the studied area are seriously polluted by Cd and Mn, and Celosia argentea is a potential plant material for the remediation of the co-contaminated soil. [ABSTRACT FROM AUTHOR]

Soils with high lead (Pb) levels can be decontaminated with the use of tolerant plants. Their effectiveness may be increased with added soil N due to boosted plant vigor, but such an agronomic practice has not been widely reported so far. In this work, purslane (Portulaca oleracea) was tested in a pot experiment as a potential phytoremediation species using soil spiked with Pb at doses of 0, 150, 300, 600, and 900 mg kg−1 (referred to as Pb(0), Pb(150), Pb(300), Pb(600), and Pb(900), respectively) with added N (referred to as N(1); at 300 kg N ha−1) and without added N (N(0)). We found that added Pb did not cause any adverse effects on plant growth (height, and aerial and root dry biomass) and physiological parameters, which were boosted with added N. Lead plant concentration and uptake significantly increased with added N, a finding that confirms our hypothesis. The number of necessary harvests of purslane in order to reduce soil Pb to half its initial concentration was also calculated and found to decrease with added N, being 131 at Pb(900)N(1). Although results indicate the potential of purslane as a phytoremediation species, further research is needed under real field conditions.

In the present work, both the iron nanoparticles (INPs) by the chemical reduction method were synthesized and the hydrogen gas was produced during the reaction. In the nanoparticle synthesis method, the leach solution prepared from the branches and leaves of Pinus brutia , iron accumulator plant, was used as an iron ion source whilst sodium borohydride (NaBH 4) was used as the reductant agent. The synthesized iron nanoparticles were characterized by UV–vis spectrophotometer, X-ray Diffractometer (XRD), Scanning Electron Microscope (SEM), and Energy Dispersive X-ray Spectroscopy (EDX). According to the characterization results; INPs had the phases of magnetite, goethite, lepidocrocite, and zero-valent iron. The structures of INPs were porous and nearly spherical; also, the average particle size of INPs was determined to be 82.19 nm. INPs had the elements of O, Fe, Ca, Na, Mg, and Cl in descending order. On the other hand, the amount of the generated hydrogen gas was measured by the volume of the displaced water. The effects of temperature, pH, NaBH 4 amount, and poly vinyl pyrrolidone (PVP) amount on the hydrogen gas production were investigated. The results showed that temperature of 65 °C, pH = 9.0, 2.50 g NaBH 4 , and 1.0 g PVP were determined as the optimum conditions for H 2(g) production and 6000 ± 50 mL H 2(g) volume was produced under the optimum environmental conditions. The reaction kinetics was evaluated and the reaction order was found as approximately 1.3523 order and it was obtained that the reaction rate constants increased with increase in temperature as it was expected from the temperature effect. The activation energy, enthalpy, and entropy of the reaction were determined to be 46.86 kJ/mol, 44.19 kJ/mol, and –105.52 J/mol. K, respectively. Image 1 • H 2(g) was produced during iron nanoparticles synthesis with an accumulator plant. • The optimum conditions were determined as 65 °C, pH = 9, 2.5 g NaBH 4 , and 1 g PVP. • 6000 ± 50 mL H 2(g) could be produced in 80 min under the optimum conditions. • The reaction order was found as 1.35 and the studied process was endothermic. [ABSTRACT FROM AUTHOR]

In this study, three cadmium (Cd) accumulator species (Conyza canadensis, Cardamine hirsuta, and Cerastium glomeratum) were co-cultured in Cd-contaminated soil in pots to study the effects of intercropping on co-remediation. Only C. canadensis intercropped with C. glomeratum, C. hirsuta intercropped with C. glomeratum, and three-species intercropping increased plant biomass compared with their respective monocultures. The treatments of C. canadensis intercropped with C. glomeratum and three-species intercropping increased the Cd contents in roots and shoots of C. canadensis, whereas the other intercropping treatments decreased or had no significant impact on Cd contents. As for Cd accumulation, the treatments of C. canadensis intercropped with C. glomeratum, C. hirsuta intercropped with C. glomeratum, and three-species intercropping increased Cd accumulation in a single plant compared with that of their respective monocultures, whereas other intercropping treatments decreased Cd accumulation in individual plants. Only the treatments of C. canadensis intercropped with C. glomeratum and C. hirsuta intercropped with C. glomeratum increased Cd accumulation in shoots of a single pot compared with that of their respective monocultures. Therefore, C. canadensis intercropped with C. glomeratum and C. hirsuta intercropped with C. glomeratum may improve the phytoremediation efficiency for Cd-contaminated soil. [ABSTRACT FROM AUTHOR]

Paclobutrazol (PP333) can enhance the resistance capabilities of plants to stress conditions. In this study, PP333 were sprayed on the lead (Pb) and zinc (Zn) accumulator plant Pseudostellaria maximowicziana, which was planted in Pb-Zn contaminated soil, and the effects of PP333 on Pb and Zn accumulation levels in P. maximowicziana were studied. Spraying 10 mg/L PP333 increased, while 20, 30 and 50 mg/L PP333 decreased, the biomass of P. maximowicziana compared with the control. The 10 mg/L PP333 had no significant effects on the photosynthetic pigment contents of P. maximowicziana compared with the control, while the other doses increased the contents. The activities of antioxidant enzymes (superoxide dismutase, peroxidase and catalase) and the Pb and Zn concentrations in P. maximowicziana were increased by PP333 compared with the control. These items had the increase trend with the increase of PP333 concentrations. Only 10 and 20 mg/L PP333 increased the amount of Pb extracted by P. maximowicziana shoots, while all of the doses increased the amount of Zn extracted by P. maximowicziana shoots. Thus, low concentration of PP333 could promote the growth and heavy metal extraction ability of P. maximowicziana shoots, with the 10 mg/L being the best. [ABSTRACT FROM AUTHOR]

Intercropping affects heavy-metal uptake in plants. In this study, three cadmium (Cd)-accumulator species ( Stellaria media, Malachium aquaticum, and Galium aparine) were intercropped together in Cd-contaminated soil to study the effects of intercropping on co-remediation . Mutual intercropping significantly increased the biomasses of S. media, M. aquaticum, and G. aparine compared with their respective monocultures. The photosynthetic pigment contents of three species were not significantly affected by mutual intercropping. Mutual intercropping did not increase the Cd contents in roots and shoots of G. aparine, but it increased the Cd contents in roots of S. media and M. aquaticum. It also decreased the Cd contents in shoots of S. media and M. aquaticum. Only G. aparine intercropped with M. aquaticum and three-species intercropping increased Cd-accumulation levels in whole plants of each species. Only S. media intercropped with M. aquaticum and three-species intercropping increased the Cd accumulation at the whole plant level in every plant in a single pot, with S. media intercropped with M. aquaticum showing the greatest increase. Therefore, S. media intercropped with M. aquaticum and three-species intercropping may improve the efficiency of phytoremediation of Cd-contaminated soil, with S. media intercropped with M. aquaticum representing the best combination. [ABSTRACT FROM AUTHOR]

The effects of uniconazole (S-3307) application on the growth and cadmium (Cd) accumulation of accumulator plantMalachium aquaticum(L.) Fries. were studied through a pot experiment. The application of S-3307 increased the biomass and photosynthetic pigment content ofM. aquaticumin Cd-contaminated soil, and also improved the superoxide dismutase (SOD) and peroxidase (POD) activities inM. aquaticum. Application of S-3307 increased Cd content in shoots and decreased Cd content in roots ofM. aquaticum, but the translocation factor (TF) ofM. aquaticumincreased with the increase of S-3307 concentration. For phytoextraction, the application of S-3307 increased Cd extractions by roots, shoots and whole plants ofM. aquaticum, and the maxima were obtained at 75 mg L−1S-3307, which increased by 22.07%, 37.79% and 29.07%, respectively, compared with their respective controls. Therefore, S-3307 can be used for enhancing the Cd extraction ability ofM. aquaticum, and 75 mg L−1S-3307 was the optimal dose. [ABSTRACT FROM AUTHOR]

The cadmium phytoremediation capacity of the halophyte plant Bolboschoenus maritimus (L.) Palla and the influence of water salinity were assessed in a greenhouse experiment, in order to better understand the bioremediation capacity of this plant. Three concentrations of cadmium (0, 50 and 100 μg l) and four salinity conditions (0, 5, 10 and 20) were chosen to evaluate the cadmium accumulation, in order to test these plants as a potential phytoremediation tool in brackish environments. The cadmium content in water and plants (underground organs, stems and leaves) was analysed with graphite furnace atomic absorption spectrometry. All the plants submitted to salinity 20 and in the three cadmium treatments died. The plants' survival was highest in the lowest salinities, where highest growth and biomasses were also obtained. The plants presented more cadmium content in the rhizomes, followed by stems and even less in leaves. The salt stress of the plants interfered with their cadmium accumulation capacity. The highest cadmium accumulation in the rhizomes occurred at salinity 0, while the salinities 0 and 5 were the most adequate for stems and leaves. The experiment pointed out that B. maritimus represents a good possible intervenient for cadmium bioremediation in freshwater and low salinity brackish water environments, but its use is limited in the habitats of higher salinity. [ABSTRACT FROM AUTHOR]

Macro- and micronutrients concentrations and PTEs contents in soils and plants (rice) from the rice district in the Venetian territory (NE Italy) have been determined by Inductive Coupled Plasma Optical Emission Spectrometry (ICP-OES), with the following aims: - to determine the background levels of macro- and microelements in the study area; - to assess possible contamination of soils and plants; - to calculate the Translocation Factor (TF) of metals from soil to plant, and the possible hazard for human health. Four rice plots with different rotation systems were investigated from seedling time to harvesting; sampling of soils (0–30 cm) and plants was carried out 4 times during growing season (three replicates). Rice plants were separated into the roots, stems, leaves and grains, and then oven-dried. Chemical and physical analyses were carried out at the Soil Science Lab of the University of Bologna and Venice, respectively. The results obtained point to a land with high soil contamination by Li and TI. The total concentrations of most studied metals (Al, As, Be, Cd, Co, Cr, Cu, Fe, Ni, Pb, Sb, Sn, Sr, V, Zn) in the soil samples fell in the natural geochemical background concentration levels, even though the concentration levels of some of them (e.g. Sn) overcame the Italian threshold limits for green areas (DM 152/2006). Most elements are likely associated with the geochemistry of the parent material. Antimony and Ti contents in soils are positively correlated with soil pH, while As, Be, Fe, Li, Sb, Ti, Tl and Zn are negatively correlated with organic matter content. With the exception of strontium, soil metals are always correlated between variable couples. Heavy metals in plants vary according to the sampling season, texture and moisture, and soil pH. Most non-essential trace elements are accumulated in rice roots and, only in cases of essential micronutrients, in leaves. Therefore, rice can be assumed as an excluder plant (i.e. metal in the roots < metal in soil) for Li, Sn, Tl. The results of multiple linear regression analysis showed that soil extractable P and total Ca played an important role in predicting annual grain yield of rice. The average translocation of metals from the soil to the root was found to be > 1, irrespective of the essential/not essential function; conversely, only essential elements (Cu, Fe, Mn, Zn) are translocated rather easily from the roots to leaves (TF ≤ 1) via xylem, and very little are translocated to grains (TF ≪ 1). Rice plants were able to accumulate non essential metals in their tissues especially in the roots, but not in the edible part, and this could be useful for the restoration of contaminated sites with a very limited hazard for human population consuming rice crops. [ABSTRACT FROM AUTHOR]

Field sampling of two prevalent weeds (Sida acuta and Pennisetum purpureum) growing on cement-polluted soil was carried out seasonally to assess the root and leaf contents of Pb, Cu, Cr, Cd and Zn. Concentrations of heavy metal in corresponding soils (total and bioavailable) were also determined and data generated were used to calculate the respective transfer factors (TFs) and translocation indices (Tis) of metals in the weed species. The results of the TFs and Tis were used to evaluate the potential ability of these weed species to accumulate heavy metals in their tissues and suitability or phytoremediation. Findings indicated that S. acuta and P. purpureum are suitable for phytostabilization of Cr, Cd and Zn in cement-polluted soil while Cr and Cd can be phytoextracted by these two weed species from cementpolluted soil. [ABSTRACT FROM AUTHOR]