Impact of chelator-induced phytoextraction of cadmium on yield and ionic uptake of maize

Enhanced phytoextraction uses soil chelators to increase the bioavailability of heavy metals. This study tested the effectiveness of ethylenediaminetetraacetic acid (EDTA) and citric acid in enhancing cadmium (Cd) phytoextraction and their effects on the growth, yield, and ionic uptake of maize (Zea mays). Maize seeds of two cultivars were sown in pots treated with 15 (Cd₁₅) or 30 mg Cd kg^?1 soil (Cd₃₀). EDTA and citric acid at 0.5 g kg^?1 each were applied 2 weeks after germination. Results demonstrated that the growth, yield per plant, and total grain weight were reduced by exposure to Cd. EDTA increased the uptake of Cd in shoots, roots, and grains of both maize varieties. Citric acid did not enhance the uptake of Cd, rather it ameliorated the toxicity of Cd, as shown by increased shoot and root length and biomass. Cadmium toxicity reduced the number of grains, rather than the grain size. The maize cultivar Sahiwal-2002 extracted 1.6% and 3.6% of Cd from soil in both Cd+ EDTA treatments. Hence, our study implies that maize can be used to successfully phytoremediate Cd from soil using EDTA, without reducing plant biomass or yield.     

Enhanced accumulation of Cd in castor (Ricinus communis L) by soil-applied chelators

Phytoextraction has been identified as one of the most propitious methods of phytoremediation. This pot experiment were treated with varying amounts of (ethylenediamine triacetic acid) EDTA 3–15, (Nitriloacetic acid) NTA 3–10, (Ammonium citrate) NH₄ citrate 10 – 25 mmol and one mg kg^–1Cd, filled with 5 kg soil. The addition of chelators significantly increased Cd concentration in soil and plant. The results showed that maximum Cd uptake was noted under root, shoot and leaf of castor plant tissue (2.26, 1.54, and 0.72 mg kg^–1) under EDTA 15, NTA 10, and NH₄ citrate 25 mmol treatments respectively, and in soil 1.08, 1.06 and 0.52 mg kg^–1 pot^–1 under NH₄ citrate 25, NTA 10 and EDTA 15 mmol treatments respectively, as against to control (p < 0.05). Additions of chelators reduction biomass under the EDTA 15 mmol as compared to other treatments, However, Bioconcentration factor (BCF), translocation factor (TF) and remediation factor (RF) were significantly increased under EDTA 15 and NH₄ citrate 25 mmol as against control. Our results demonstrated that castor plant proved satisfactory for phytoextraction on contaminated soil, and EDTA 15 and NH₄ citrate 25 mmol had the affirmative effect on the Cd uptake in the artificial Cd-contaminated soil.     

Identifying the functional groups and the influence of synthetic chelators on Cd availability and microbial biomass carbon in Cd-contaminated soil

Synthetic chelators play an important role in boosting the microbial biomass carbon (MBC), dissolved organic carbon (DOC), and heavy metal solubility in a contaminated soil toward a sustainability of environment for agricultural crops. Castor plant was grown under different levels of Cd contaminated soil (?Cd and +Cd) following adding three chelating agents, ethylenediaminetetraacetic acid (H₄EDTA), nitriloacetic acid (H₃ NTA), and NH₄ citrate (ammonium citrate) to the soil at rates of 10, 15, and 25 mmol in 5 kg of soil per pot. The highest bioavailable Cd concentrations in soil and castor plant were obtained from NH₄ citrate and H₄EDTA treatments in the contaminated soil. Fourier transform infrared (FTIR) analysis showed that NH₄ citrate was the most effective chelator in Cd-contaminated soil. MBC and DOC contents were significantly increased and reached at 81.98–80.37 and 1.96–1.90 mg kg^?1 respectively, in the (H₃ NTA) and NH₄ citrate treatments in Cd-contaminated soil. Further research is needed to investigate the use of chelators in the phytoextraction of Cd-contaminated soils under field conditions and whether it may be beneficial in accelerating the phytoextraction of Cd through hyperaccumulating plants.     

Enhancing Phytoremediation Potential of Pennisetum clandestinum Hochst in Cadmium-Contaminated Soil Using Smoke-Water and Smoke-Isolated Karrikinolide

The use of plant growth regulators (PGRs) and biostimulants to enhance phytoextraction is gaining popularity in phytoremediation technology. This study investigated the stimulatory effects of smoke-water (SW), a smoke-derived compound karrikinolide (KAR₁) and other known plant growth regulators (PGRs) [gibberellic acid (GA₃), kinetin (Kin) and indole-3-butyric acid (IBA)] to enhance the phytoextraction potential of Pennisetum clandestinum. Pennisetum clandestinum seedlings were grown for 10 weeks in vermiculite using Hoagland's nutrient solution and were treated with cadmium (Cd) (2, 5, and 10 mg L^?1) and SW, KAR₁ and PGRs. KAR₁ exhibited positive effects on shoot and root dry weight (140 and 137 mg respectively) at the highest concentration of Cd (10 mg L^?1) compared to all the other treatments. KAR₁ and SW treatments used in the present study significantly improved the phytoextraction potential of P. clandestinum (602 and 575 mg kg^?1 respectively) compared to the other tested PGRs. This is the first report on the use of SW and KAR₁ to enhance phytoremediation potential in P. clandestinum. Further studies are needed to elucidate the exact mechanisms of smoke constituents involved in phytoextraction potential of plant species.     

EDTA-assisted phytoextraction of lead and cadmium by Pelargonium cultivars grown on spiked soil

The aim of this study was to assess EDTA-assisted Pb and Cd phytoextraction potential of locally grown Pelargonium hortorum and Pelargonium zonale. Plants were exposed to different levels of Pb (0–1500?mg kg^?1) and Cd (0–150?mg kg^?1) in the absence or presence of EDTA (0–5?mmol kg^?1). P. hortorum and P. zonale accumulated 50.9% and 42.2% higher amount of Pb in shoots at 1500?mg kg^?1 Pb upon addition of 5?mmol kg^?1 EDTA. Plant dry biomass decreased 46.8% and 64.3% for P. hortorum and P. zonale, respectively at the combination of 1500?mg kg^?1 Pb and 5?mmol kg^?1 EDTA. In Cd and EDTA-treated groups, P. hortorum and P. zonale accumulated 2.7 and 1.6-folds more Cd in shoots at 4 and 2?mmol kg^?1 EDTA, respectively, in 150?mg Cd kg^?1 treatment. Plant dry biomass of P. hortorum and P. zonale was reduced by 46.3% and 71.3%, respectively, in soil having 150?mg Cd kg^?1 combined with 5?mmol kg^?1 EDTA. Translocation factor and enrichment factor of both plant cultivars at all treatment levels were >1. Overall, the performance of P. hortorum was better than that of P. zonale for EDTA-assisted phytoextraction of Pb and Cd.     

Enhanced phytoremediation of cadmium and/or benzo(a)pyrene contaminated soil by hyperaccumlator Solanum nigrum L.

The role of same amendment on phytoremediating different level contaminated soils is seldom known. Soil pot culture experiment was used to compare the strengthening roles of cysteine (CY), EDTA, salicylic acid (Sa), and Tween 80 (TW) on hyperaccumulator Solanum nigrum L. phytoremediating higher level of single cadmium (Cd) or Benzo(a)pyrene (BAP) and their co-contaminated soils. Results showed that the Cd capacities (ug pot^?1) in shoots of S. nigrum in the combined treatment T_{0.1EDTA+0.9CY} were the highest for the 5 and 15 mg kg^?1 Cd contaminated soils. When S. nigrum remediating co-contaminated soils with higher levels of Cd and BAP, that is, 5 mg kg^?1 Cd + 1 mg kg^?1 BAP and 15 mg kg^?1 Cd + 2 mg kg^?1 BAP, the treatment T_{0.9CY+0.9Sa+0.3TW} showed the best enhancing remediation role. This results were different with co-contaminated soil with 0.771 mg kg^?1 Cd + 0.024 mg kg^?1 BAP. These results may tell us that the combine used of CY, SA, and TW were more useful for the contaminated soils with higher level of Cd and/or BAP. In the combined treatments of Sa+TW, CY was better than EDTA.     

Phytoextraction of Cadmium and Zinc By Sedum plumbizincicola Using Different Nitrogen Fertilizers,a Nitrification Inhibitor and a Urease Inhibitor

Cadmium (Cd) and zinc (Zn) phytoavailability and their phytoextraction by Sedum plumbizincicola using different nitrogen fertilizers, nitrification inhibitor (dicyandiamide, DCD) and urease inhibitor (N-(n-Butyl) thiophosphoric triamide, NBPT) were investigated in pot experiments where the soil was contaminated with 0.99 mg kg^?1 of Cd and 241 mg kg^?1 Zn. The soil solution pH varied between 7.30 and 8.25 during plant growth which was little affected by the type of N fertilizer. The (NH₄)₂SO₄+DCD treatment produced higher NH₄⁺?N concentrations in soil solution than the (NH₄)₂SO₄ and NaNO₃ treatment which indicated that DCD addition inhibited the nitrification process. Shoot Cd and Zn concentrations across all treatments showed ranges of 52.9–88.3 and 2691–4276 mg kg^?1, respectively. The (NH₄)₂SO₄+DCD treatment produced slightly higher but not significant Cd and Zn concentrations in the xylem sap than the NaNO₃ treatment. Plant shoots grown with NaNO₃ had higher Cd concentrations than (NH₄)₂SO₄+DCD treatment at 24.0 and 15.4 mg kg^?1, respectively. N fertilizer application had no significant effect on shoot dry biomass. Total Cd uptake in the urea+DCD treatment was higher than in the control, urea+NBPT, urea+NBPT+DCD, or urea treatments, by about 17.5, 23.3, 10.7, and 25.1%, respectively.     

Effective Phytoextraction of Cadmium (Cd) with Increasing Concentration of Total Phenolics and Free Proline in Cannabis sativa (L) Plant Under Various Treatments of Fertilizers,Plant Growth Regulators and Sodium Salt

The comparative effect of fertilizers (NPK), plant growth regulators (GA₃, IAA, Zeatin) and sodium chloride (NaCl) on Cd phytoaccumulation, proline and phenolics production in Cannabis sativa was evaluated. Proline and phenolices were correlated with Cd contents in plant. Cd significantly reduced the plant growth. Fertilizers application (in combination) most significantly increased the growth (19 cm root and 47 cm shoot) on Cd contaminated soil. All treatments increased the Cd contents in plant tissues. This increase was highly significant in fertilizers treated plants (1101, 121 and 544 ppm in roots, stem and leaves respectively). Significantly positive correlation was found between Cd concentration and dry biomass of root (R² = 0.7511) and leaves (R² = 0.5524). All treatments significantly increased the proline and total phenolics and maximum was recorded in NaCl treated plants followed by fertilizers. Proline was higher in roots while phenolics in leaves. The correlation between proline and phenolics was positive in leaf (R² = 0.8439) and root (R² = 0.5191). Proline and phenolics showed positive correlation with Cd concentration in plant. Conclusively, fertilizers in combination seem to be the better option for Cd phytoextraction. Further investigation is suggested to study the role of phenolics and proline in Cd phytoextraction.     

Enhanced Phytoremediation Capacity of Chenopodium album L. Grown on Pb-Contaminated Soils Using EDTA and Reduction of Leaching Risk

Leaching of metals due to enhanced mobility during ethylenediaminetetraacetic acid (EDTA)-assisted phytoextraction has been demonstrated as one of the potential hazards associated with this technology. This study was conducted to determine phytoextraction efficiency of Chenopodium album L. for Pb and EDTA-assisted (1.5, 3, and 9 mmol kg^?1) phytoextraction and potential for leaching of Pb. The results demonstrated that BCF_shoot (bioconcentration factor) was relatively higher than the BCF_root. Translocation factor in the shoot was higher than the roots. Thus, plant species would be applicable for Pb phytoextraction. EDTA enhanced translocation of Pb from roots to shoots. Lead content in the plant parts was maximum in the shoot and root of 9EDTA and 3EDTA, respectively. However, there was no significant difference between 3EDTA and 9EDTA. Lead concentration in the plant parts increased significantly from vegetative stage into flowering stage. Lead content taken up by the plant was lowest when EDTA was applied in a single dose. Therefore, application of EDTA in several increments rather than a single split reduced the leaching risk. Totally, optimum phytoextraction was observed when 3 mmol kg^?1 EDTA was added in triple dosage 60 days after the plant cultivation under triple application mode. The results indicated the plant has the potential for Pb phytoextraction, but it should not be used unless the biomass containing such accumulated metal is removed for disposal. Significant improvement over current ETDA-assisted phytoextraction of Pb may be possible but should be implemented cautiously because of environmental risk.     

Cadmium Removal Potential from Contaminated Soil by Tagetes erecta L. and Panicum maximum: Influence of Soil pH

The potential for cadmium (Cd) removal from contaminated soil by two species—marigold (Tagetes erecta L.) and Guinea grass (Panicum maximum)—was investigated in pot culture experiments in a greenhouse in triplicate. The concentration of Cd was varied from 50 to 200 mg kg^?1 and the pH was varied from 5.0 to 7.5 to investigate the effect of pH on Cd uptake. The results showed that total biomass of Guinea grass was around nine and seven times higher than that of marigold for Cd treatments of 50 and 100 mg kg^?1 at pH 5.0, respectively. Total cadmium uptake at Cd treatments of 50 and 100 mg kg^?1 at pH 5.0 by Guinea grass was 19.28 ± 3.14 and 36.06 ± 4.28 mg kg^?1, respectively, and for marigold was 15.66 ± 4.17 and 20.38 ± 3.24 mg kg^?1, respectively. The total Cd uptake by Guinea grass was 1.23 and 1.77 higher than that of marigold at Cd treatments of 50 and 100 mg kg^?1, respectively, at pH 5.0 due to higher biomass. The maximum Cd uptake by marigold and Guinea grass occurred at pH 5.0 at Cd treatment of 100 mg kg^?1. The results clearly show that the two species behave very differently for Cd uptake. Guinea grass is easy to grow, drought tolerant and, due to its higher biomass, it can be used for remediation of Cd-contaminated soil.     

Augmented Phytoextraction of Lead (Pb2+)-Polluted Soils: A Comparative Study of the Effectiveness of Plant Growth Regulators,EDTA, and Plant Growth–Promoting Rhizobacteria

Abstract

The role of gibberellic acid (GA3), indole-3-acetic acid (IAA), plant growth–promoting bacteria (Rhizobium and Azotobacter), and a synthetic chelator (EDTA; ethylenediaminetetraacetic acid) in lead (Pb) phytoextraction was evaluated using Parthenium hysterophorus (dicot, unpalatable noncrop) and Zea mays (monocot food/forage crop) plants at the flowering stage. Various plant parts were analyzed by atomic absorption/flame spectrophotometer for their Pb content. Both plant growth regulators and both growth-promoting bacteria significantly increased the plant growth in Pb-polluted soils, whereas EDTA significantly decreased growth and biomass of both plants. EDTA increased the Pb uptake (μg g^?1 dry biomass), but the total plant Pb accumulation was decreased. GA3 and IAA significantly increased both uptake and translocation, and the maximum total Pb in the entire plant of Parthenium was found with GA3 foliar spray, whereas in Z. mays the total Pb was maximum in the plant treated with GA3 in combination with EDTA, followed by the GA3 foliar spray treatment. Overall, the GA3 foliar application showed superior response compared with all other treatments. Further research is recommended to observe the role of endogenous GA3 levels in correlation with metal phytoextraction in different plants.     

Phytoextraction of Risk Elements by Willow and Poplar Trees

To characterize the phytoextraction efficiency of two clones of willow trees (Salix x smithiana Willd., Salix rubens) and two clones of poplar trees (Populus nigra x maximowiczii, Populus nigra Wolterson) were planted in contaminated soil (0.4–2.0 mg Cd.kg^?1, 78–313 mg Zn.kg^?1, 21.3–118 mg Cu.kg^?1). Field experiment was carried out in Czech Republic. The study investigated their ability to accumulate heavy metals (Cd, Zn, and Cu) in harvestable plant parts. The poplars produced higher amount of biomass than willows. Both Salix clones accumulated higher amount of Cd, Zn and Cu in their biomass (maximum 6.8 mg Cd.kg^?1, 909 mg Zn.kg^?1, and 17.7 mg Cu.kg^?1) compared to Populus clones (maximum 2.06 mg Cd.kg^?1, 463 mg Zn.kg^?1, and 11.8 mg Cu.kg^?1). There were no significant differences between clones of individual species. BCs for Cd and Zn were greater than 1 (the highest in willow leaves). BCs values of Cu were very low. These results indicate that Salix is more suitable plant for phytoextraction of Cd and Zn than Populus. The Cu phytoextraction potential of Salix and Populus trees was not confirmed in this experiment due to low soil availability of this element.     

Tolerance of Ricinus communis L. to Cd and screening of high Cd accumulation varieties for remediation of Cd contaminated soils

Response of castor (Ricinus communis L.) to cadmium (Cd) was assessed by a seed-suspending seedbed approach. Length of total radicle was the most sensitive indicator of Cd tolerance among the tested germination and growth characters. The ED₅₀ value for Cd was 11.87 mg L^?1, indicating high Cd tolerance in castor. A pot experiment was conducted by growing 46 varieties of castor under CK (without Cd) and Cd1 (10 mg kg^?1 of Cd) and Cd2 (50 mg kg^?1 of Cd) treatments to investigate genotype variations in growth response and Cd accumulation of castor under different Cd exposures. Castor possessed high Cd accumulation ability; average shoot and root Cd concentrations of the 46 tested varieties were 21.83 and 185.43 mg kg^?1, and 174.99 and 1181.96 mg kg^?1 under Cd1 and Cd2, respectively. Great variation in Cd accumulation was observed among varieties, and Cd concentration of castor was genotype dependent. The correlation between biomass and Cd accumulation was significantly positive, while no significant correlation was observed between Cd concentration and Cd accumulation, which indicated that biomass performance is the dominant factor in determining Cd accumulation ability.     

Use of Energy Crop (Ricinus communis L.) for Phytoextraction of Heavy Metals Assisted with Citric Acid

Ricinus communis L. is a bioenergetic crop with high-biomass production and tolerance to cadmium (Cd) and lead (Pb), thus, the plant is a candidate crop for phytoremediation. Pot experiments were performed to study the effects of citric acid in enhancing phytoextraction of Cd/Pb by Ricinus communis L. Citric acid increased Cd and Pb contents in plant shoots in all treatments by about 78% and 18–45%, respectively, at the dosage of 10 mM kg^?1 soil without affecting aboveground biomass production. Addition of citric acid reduced CEC, weakened soil adsorption of heavy metals and activated Cd and Pb in soil solutions. The acid-exchangeable fraction (BCR-1) of Pb remained lower than 7% and significantly increased with citric acid amendment. Respective increases in soil evaluation index induces by 14% and 19% under the Cd1Pb50 and Cd1Pb250 treatments upon addition of citric acid resulted in soil quality improvement. Ricinus communis L. has great potential in citric acid-assisted phytoextraction for Cd and Pb remediation.     

Calcium chloride and gibberellic acid protect linseed (Linum usitatissimum L.) from NaCl stress by inducing antioxidative defence system and osmoprotectant accumulation

Salinity stress affects many metabolic facets of plants and induces anatomical and morphological changes resulting in reduced growth and productivity. To overcome the damaging effects of salinity, different strategies of the application of nutrients with plant hormones are being adopted. The present study was carried out with an aim to find out whether application of calcium chloride (CaCl₂) and gibberellic acid (GA₃) could alleviate the detrimental effects of salinity stress on plant metabolism. Fifteen days old plants were supplied with (1) 0 mM NaCl + 0 mg CaCl₂ kg^?1 sand + 0 M GA₃ (control, T0); (2) 0 mM NaCl + 10 mg CaCl₂ kg^?1 sand + 0 M GA₃ (T1); (3) 0 mM NaCl + 0 mg CaCl₂ kg^?1 sand + 10^?6 M GA₃ (T2); (4) 150 mM NaCl + 0 mg CaCl₂ kg^?1 sand + 0 M GA₃ (T3); (5) 150 mM NaCl + 10 mg CaCl₂ kg^?1 sand + 0 M GA₃ (T4); (6) 150 mM NaCl + 0 mg CaCl₂ kg^?1 sand + 10^?6 M GA₃ (T5); (7) 150 mM NaCl + 10 mg CaCl₂ kg^?1 sand + 10^?6 M GA₃ (T6). To assess the response of the crop to NaCl, CaCl₂ and GA₃, plants were uprooted randomly at 60 days after sowing. The presence of NaCl in the growth medium decreased all the growth and physio-biochemical parameters, except electrolyte leakage, proline (Pro) and glycine betaine (GB) content, thiobarbituric acid reactive substances (TBARS), H₂O₂ content, activities of superoxide dismutase (SOD) and catalase (CAT) and leaf Na content, which exhibited an increase of 37.6, 29.3, 366.9, 107.5, 59.1, 17.1, 28.4 and 255.2%, respectively, compared to the control plants. However, application of CaCl₂ in combination with GA₃ appears to confer greater osmoprotection by the additive role with NaCl in Pro and GB accumulation. Although the activities of antioxidant enzymes (SOD, CAT and POX) were increased by salt stress, the combined application of CaCl₂ and GA₃ to salt-stressed plants further enhanced the activities of these enzymes by 25.1, 6.7 and 47.8%, respectively, compared to plants grown with NaCl alone. The present study showed that application of CaCl₂ and GA₃ alone as well as in combination mitigated the adverse effect of salinity, but combined application of these treatments proved more effective in alleviating the adverse effects of NaCl stress.     

Uptake and Bioaccumulation of Pentachlorophenol by Emergent Wetland Plant Phragmites australis (Common Reed) in Cadmium Co-contaminated Soil

Despite many studies on phytoremediation of soils contaminated with either heavy metals or organics, little information is available on the effectiveness of phytoremediation of co-occurring metal and organic pollutants especially by using wetland species. Phragmites australis is a common wetland plant and its potential for phytoremediation of cadmium pentachlorophenol (Cd-PCP) co-contaminated soil was investigated. A greenhouse study was executed to elucidate the effects of Cd (0, 10, and 20 mg kg^?1) without or with PCP (0, 50, and 250 mg kg^?1) on the growth of the wetland plant P. australis and its uptake, accumulation and removal of pollutant from soils. After 75 days, plant biomass was significantly influenced by interaction of Cd and PCP and the effect of Cd on plant growth being stronger than that of PCP. Coexistence of PCP at low level lessened Cd toxicity to plants, resulting in improved plant growth and increased Cd accumulation in plant tissues. The dissipation of PCP in soils was significantly influenced by interactions of Cd, PCP and plant presence or absence. As an evaluation of soil biological activities after remediation soil enzyme was measured.     

Effects of biochar and nitrogen addition on nutrient and Cd uptake of Cichorium intybus grown in acidic soil

Biochar is an organic amendment used for soil remediation, there are only a few studies documenting the effects of nitrogen on the role of biochar in contaminated soils. A pot experiment was conducted to investigate the impacts of biochar (0%, 1%, and 2.5%, w/w) and nitrogen (0, 100, and 200 mg N kg^?1) on plant growth, nutrient and cadmium (Cd) uptake of Cichorium intybus. N, P, Ca, Mg, and Cd concentrations increased with N level in 0% and 1% biochar treatments. In plants treated with 2.5% biochar, 200 mg N kg^?1 addition caused significant reductions of N, P, Ca, Mg, and Cd concentrations in comparison to 100 mg N kg^?1 treatments. Nitrogen promoted shoot biomass at all biochar treatments, while biochar had no effect on shoot biomass in 0 and 200 mg N kg^?1 addition treatments. Nitrogen also significantly increased N, P, K, Ca, Mg, and Cd contents in the 0% and 1.5% biochar addition treatments. Although soil DTPA-extractable Cd concentration showed the lowest values in 1% biochar in combination with 100 and 200 mg N kg^?1 addition treatments, lowest shoot Cd concentration, and relatively high shoot biomass occurred in the 2.5% biochar + 200 mg N kg^?1 treatment. Based on these results, biochar application at its highest rate (2.5%) in combination with high N supply (200 mg N kg^?1) contributed to both crop yield and agricultural product safety. N input alone might increase the risk of human health, and the optimum N dose should be determined during phytostabilization process.     

<Emphasis Type="Italic">In vitro</Emphasis> effects of GA<Subscript>3</Subscript> on morphogenesis of CIP potato explants and acclimatization of plantlets in field

Improvement of potato has been accomplished using conventional and non-conventional approaches coupled with numerous tissue culture procedures. The aim of the present study was to assess the efficacy of gibberellic acid (GA₃) on the morphogenesis of International Potato Center (CIP) potato explants and acclimatization of plantlets in the field. Nodal segments as an explant source (1–1.5 cm) were isolated from 31 CIP potato plantlets and were inoculated into Murashige and Skoog (MS) medium supplemented with 0.0 (control), 0.1, 0.5, or 1.0 mg L^?1of GA₃. The variation in growth parameters of the cultivars was then observed. The highest shoot induction occurred in MS medium containing 1.0 mg L^?1 GA₃ with an increase in the inter-nodal distance between nodes as compared to other treatments. Higher concentration (1.0 mg L^?1) of GA₃ significantly increased plant height and root length in the treated germplasm however; this concentration was inhibitory to the number of nodes and roots per plant. The number of leaves was significantly increased in plants receiving GA₃ treatment at lower concentration (0.1 mg L^?1). The 31 CIP genotypes were transplanted to the field and checked for yield quality traits. It was concluded from the results that GA₃ had significant effects on morphogenesis and was effective in the acclimatization of CIP potato plantlets in field.     

Enhancing of Phytoremediation Efficiency Using Indole-3-Acetic Acid (IAA)

In this study, a pot experiment using Solanum nigrum L. grown in cadmium-contaminated soil was conducted in a greenhouse. Indole-3-acetic acid (IAA) was applied at three different concentrations (1 mg L^?1, 10 mg L^?1, and 100 mg L^?1) to examine the effects on phytoremediation efficiency. According to the experimental results, IAA increased the shoot biomass of S. nigrum significantly, by 124% at the highest concentration used, and increased the Cd concentration in the shoot of S. nigrum by 16%. The Cd extraction amount from a single plant was increased by up to 158%, demonstrating potential practical application for remediation practice.     

Mycorrhizal symbiosis and phosphorus fertilization effects on Zea mays growth and heavy metals uptake

Arbuscular mycorrhizal fungi (AMF) can promote plant growth and reduce plant uptake of heavy metals. Phosphorus (P) fertilization can affect this relationship. We investigated maize (Zea mays L.) uptake of heavy metals after soil AMF inoculation and P fertilization. Maize biomass, glomaline and chlorophyll contents and uptake of Fe, Mn, Zn, Cu, Cd and Pb have been determined in a soil inoculated with AMF (Glomus aggregatum, or Glomus intraradices) and treated with 30 or 60 µg P-K₂HPO₄ g^?1 soil. Consistent variations were found between the two mycorrhizal species with respect to the colonization and glomalin content. Shoot dry weight and chlorophyll content were higher with G. intraradices than with G. aggregatum inoculation. The biomass was highest with 30 µg P g^?1 soil. Shoot concentrations of Cd, Pb and Zn decreased with G. aggregatum inoculation, but that of Cd and Pb increased with G. intraradices inoculation. Addition of P fertilizers decreased Cd and Zn concentrations in the shoot. AMF with P fertilization greatly reduced maize content of heavy metals. The results provide that native AMF with a moderate application rate of P fertilizers can be exploited in polluted soils to minimize the heavy metals uptake and to increase maize growth.