Chromium In Roots Research Articles

Physiological responses of chickpea (Cicer arietinum) against chromium toxicity

Plant scientists are most concerned about metal toxicity and detoxification strategies because metals accumulate in plants and enter the food chain. To provide scientific references on metal detoxification strategies, we investigated the defense mechanism of chickpea as it can grow properly in a chromium-contaminated environment. Chickpea plants were grown on the hydroponic solution treated with chromium, and different biochemical analyses were conducted to determine the physiological responses to chromium toxicity. When the roots of chromium-treated seedlings were compared to control plants, they contained a significant amount (six times more) of chromium, but its translocation to shoots was limited, indicating the retention of excess chromium in roots. The reason behind this retention is chromium adsorption on the root surface as an attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR) study reveal that roots induce divergent functional groups. Furthermore, the catalase (1.12 ± 6 × 10−2 U/min/mg) and peroxidase (0.97 ± 8 × 10−2 U/min/mg) enzyme activities play a partial role in removing oxidative stress in roots. However, no effective roles of exogenous salicylic acid (SA) and citric acid (CA) were observed in this mechanism. Findings of this study suggest that root-induced functional groups provide negative charges for the binding of chromium cations, resulting in the adsorption of chromium on the root surface. Adsorption of chromium due to surface charges preventing the entrance of chromium into plants may provide an avoidance strategy against chromium toxicity in local chickpea plants.

The Physiological Responses of Water Hyacinth (Eichhornia crassipes (Mart). Solms) and Water Lettuce (Pistia stratiotes L.) as Trivalent Chromium Bioaccumulator

Chromium is one of the heavy metals used in industrial fields, i.e., metallurgical industry, chemical industry, heat-retardant, and leather tanning industry. Untreated wastewater from these industries can pollute rivers and threaten the aquatic ecosystem. Some aquatic plants such as water hyacinth ( Eic hhornia crassipes ) and water lettuce ( Pistia stratiotes ) have been known as metal hyperaccumulators and can be used as phytoremediator for polluted water. This study aims to determine the physiological and morphological responses of water hyacinth and water lettuce plants treated by different concentrations of trivalent chromium and to study which plant is effective for trivalent chromium removal. The experiment was conducted for 2 week at screen house. After two weeks, the plants were harvested and the weight was measured. The samples were separated into shoot and root and were analyzed for Cr content, chlorophyll, proline and CAT enzyme activity. The results of this study indicated that the levels of water hyacinth chromium in roots and leaves are lower (863.988 mg/Kg, 899.126 mg/Kg, 685.877 mg/Kg for treatment 40 ppm, 80 ppm, and 120 ppm respectively) than the levels of chromium in water lettuce (1584.264 mg/Kg, 1660 mg/Kg, 1413 mg/Kg for treatment 40 ppm, 80 ppm, and 120 ppm respectively). Physiological parameter, i.e., chlorophyll and proline levels in water hyacinth and water lettuce from all concentration treatment did not differ significantly (P> 0.05). The activity of the catalase enzyme in water hyacinth and water lettuce decreased with increasing chromium levels. The highest catalase enzyme activity was observed in control treatment of water lettuce (1.61 unit/mg) and 40 ppm treatment of water hyacinth (1.006 unit/mg). The highest biomass dry weight of both plants was found in plants with control treatment (15.38 gr and 8.48 gr for water hyacinth and water lettuce respectively). Therefore, we concluded that water lettuce is better for trivalent chromium removal than water hyacinth.

Phytoremediation potential of Pistia stratiotes and Eichhornia crassipes to remove chromium and copper

ABSTRACTPhytoremediation is a cost-effective and eco-friendly process to remove heavy metals from water. A small-scale experiment was conducted to determine the phytoremediation efficiency of two macrophytes, i.e. Pistia stratiotes and Eichhornia crassipes for the removal of chromium and copper from the prepared metal solutions of different concentrations (2, 4, 6, 8 mg/L) for a period of one month. Both aquatic macrophytes showed different efficiency for the removal and accumulation of Chromium (Cr) and Copper (Cu). The dry biomass of both macrophytes increased over the period of time. The average accumulation of chromium in roots and leaves of P. stratiotes was 85 mg, 56 mg and copper was 96 mg and 70 mg, respectively whereas the average accumulation of chromium in roots and leaves of E. crassipes was 90 mg, 53 mg and copper was 86 mg, 50 mg, respectively. Higher absorbance of metals was observed in roots as compared to the leaves of both macrophytes. The concentration of metals in the solution significantly decreased from day 1 to day 30. The results of one-way ANOVA showed that removal of Cr was significantly (p < .05) greater in E. crassipes and removal of Cu was significantly (p < .05) greater in P. stratiotes.

Phytoremediation of chromium from tannery wastewater using local plant species

Abstract Phytoremediation, which is an emerging technology for cleaning up contaminated sites, is cost effective and has aesthetic advantages and long term applicability. The technology involves efficient use of plant species to remove, detoxify or immobilize contaminants in a growth matrix (soil, water or sediments) through natural processes. For this study, swamp smartweed (Polygonum coccineum), para grass (Brachiara mutica) and papyrus (Cyprus papyrus) were grown on 20 mm crushed rock filled plastic vessel watered with synthetic chromium containing solution in a greenhouse under ambient conditions. For comparison, the plants were also grown on both synthetic solution and tannery effluent with known concentration of 0.1, 0.5 and 1 mg/L Cr3+ at Bahir Dar tannery. Plants were harvested after 72 days of planting period and their roots and above ground parts were cleaned and digested through microwave digester for further analysis. Chromium in roots and shoots was determined by ICP-OES. It was observed that all plant species have the ability to remove both Cr3+ and Cr6+ from the aqueous solution for the specified initial concentration. Interestingly, using single factor analysis of variance, significant differences were also observed in their partitioning. All the three plants exhibited a significant transfer of Cr from wastewater to roots and shoots, but removal efficiency of Cr for swamp Smartweed was relatively low as compared to para grass and papyrus. On average translocation factor and removal efficiency of para grass for synthetic solution at 0.5 mg/L level and papyrus for tannery effluent at 1 mg/L level of chromium were relatively high (1.260, 83.08% and 1.715, 73.77% respectively). This finding indicated that all the tested plants (swamp smartweed, para grass and papyrus) can be used for phytoremediation of Cr3+ and Cr6+ containing wastewater discharged from industries.

Kinnow mandarin plants grafted on tetraploid rootstocks are more tolerant to Cr-toxicity than those grafted on its diploids one

This study compared the effects of chromium toxicity on the biomass, photosynthesis, antioxidants, reactive oxygen species, and nutrient concentration in Kinnow mandarin (Citrus nobilis Lour x Citrus deliciosa Ten) plants grafted on diploids (2x) and tetraploids (4x) of Poncirus trifoliata [L.], Citrus reshni, and Citrus limonia Osbeck. Plants were grown under controlled conditions and irrigated with complete nutrient solution supplemented with chromium (0.75mM). After 120-d of growth under chromium stress, plant biomass, total chlorophyll concentrations, photosynthetic activity, stomatal conductance, transpiration rate, water use efficiency, H2O2 concentrations, rate of O2− generation, lipid peroxidation, antioxidant activities (superoxide dismutase, peroxidase, catalase) and mineral nutrient concentration (Ca, Mg, K, P and Cr) were determined. Chromium inhibited plant growth, and decreased chlorophyll concentration, photosynthetic activity, stomatal conductance, transpiration rate, water use efficiency, and activities of antioxidant enzymes, but the rate of lipid peroxidation and formation of reactive oxygen species were increased. Chromium stress also caused alterations in nutrients concentration in roots and leaves. Nevertheless, it was observed that Kinnow mandarin plants grafted on the tetraploid rootstocks showed high tolerance to chromium toxicity as reported by maintaining greater biomass accumulation and less reduction in the attributes commented before. In addition, plants with 4x rootstocks had higher Ca, Mg, K and P concentration in their roots and leaves in comparison to 2x rootstocks. Plants grafted on 4x rootstock presented higher quantity of chromium in roots than leaves, suggesting that the chromium tolerance of plants with tetraploid rootstocks may be attributed to chromium sequestration to roots with lower transfer to leaves; consequently avoiding oxidative damage to green pigments and the photosynthetic apparatus.

CASE STUDY: EFFECT OF COMPOST AND HUMIC ACID IN MOBILITY AND CONCENTRATION OF CADMIUM AND CHROMIUM IN SOIL AND PLANT

The effect of compost and humic acid in mobility and concentration of cadmium and chromium in contaminated soil were investigated. Experiment was carried out with three levels of soil cadmium and chromium and two organic matters (compost and humic acid). The study was performed in a randomized complete block design with 3 replicates. Results indicated that application of organic substances enhanced movement of cadmium and chromium in soil column. Humic acid is more effective than compost on the mobility of cadmium and chromium in soil. Mobility of cadmium and chromium in the lower depths of soil column were increased. Cadmium and chromium concentration in shoots and roots enhanced due to increasing those concentration in soil and application of organic substances. Increase in cadmium in shoots can be attributed to the high mobility of this element in maize plant. Maize root chromium concentration was greater than shoot chromium concentration. Humic acid was more effective than compost as cadmium and chromium concentration in root and shoot was concerned. Low mobility of chromium in plant and accumulation of chromium in roots can be reasons of decreasing of chromium concentration in shoot of plant and its bioaccumulation.

Bacillus species enhance growth parameters of chickpea ( Cicer arietinum L.) in chromium stressed soils

Pollution of the agricultural land by the toxic chromium is a global threat that has accelerated dramatically since the beginning of industrial revolution. Toxic chromium affects both the microbial diversity as well as reduces the growth of the plants. Understanding the effect of the chromium reducing and plant growth promoting rhizobacteria on chickpea crop will be useful. Chromium reducing and plant growth promoting Bacillus species PSB10 significantly improved growth, nodulation, chlorophyll, leghaemoglobin, seed yield and grain protein of chickpea crop grown in the presence of different concentrations of chromium compared to the plants grown in the absence of bio-inoculant. The strain also reduced the uptake of chromium in roots, shoots and grains of chickpea crop compared to plants grown in the absence of bio-inoculant. This study thus suggested that the Bacillus species PSB10 due to its intrinsic abilities of growth promotion and attenuation of the toxic effects of chromium could be exploited for remediation of chromium from chromium contaminated sites.

Bioaccumulation and Chemical Form of Chromium in Leersia hexandra Swartz

The chromium bioaccumulation ability of Leersia hexandra was assessed and the chromium distribution in the deferent chemical forms in plant tissues was determined. The hydroponic experimental results indicated that the maximum chromium concentration in the dry leaf matter of Leersia hexandra reached 4302 mg kg(-1). Chromium treatment could significantly increase the proportions of oxalic integrated chromium in leaves and residue chromium in roots, which might be related to the high resistance and bioaccumulation capacity for chromium in Leersia hexandra.

Application of Secondary Ion Mass Spectrometry (SIMS) to Localize Chromium in Roots of Water Hyacinths Eichhornia crassipes (Mart.) Solms. in the Cachoeira Basin – Brazil

Application of Secondary Ion Mass Spectrometry (SIMS) to Localize Chromium in Roots of Water Hyacinths Eichhornia crassipes (Mart.) Solms. in the Cachoeira Basin – Brazil