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Cadmium (Cd) toxicity strongly influences plants growth and seed germination in crop plants. This pot trial had aimed evaluate the benefits of two different kinds of phosphorus (P)-fertilizer in the phytoremediation of Cd by

Soil contamination with toxic heavy metals [such as cadmium (Cd)] is becoming a serious global problem due to the rapid development of the social economy. This study was carried out to assess the beneficial role of two different kinds of (S)-fertilizer in the phytoremediation of Cd contaminated soil through

Increasing cadmium (Cd) pollution in agricultural soils has raised serious concerns worldwide. Several exogenous substances can be used to mitigate the toxic effects of Cd in plants. Zinc (Zn) is one of the essential plant micronutrients and is involved in several physiological functions in plants. Zn may alleviate Cd toxicity in plants owing to the chemical similarity of Zn with Cd. Published reports demonstrated that Zn can alleviate toxic effects of Cd in plants by increasing plant growth, regulating Cd uptake, increasing photosynthesis, and reducing oxidative stress. Literature demonstrated that the role of Zn on Cd accumulation by plants is very controversial and depends upon several factors including concentrations of Cd and Zn in the medium, exposure duration, plant species and genotypes, and growth conditions. This review highlights the role of Zn in reducing Cd toxicity in plants and provides new insight that proper level of Zn in plants may enhance plant resistance to excess Cd.

Heavy metal contamination is currently a major environmental concern, as most agricultural land is being polluted from municipal discharge. Among various other pollutants, cadmium (Cd), one of the most harmful heavy metals, enters into the food chain through the irrigation of crops with an industrial effluent. In the present study, a pot experiment was designed to assess the effect of different nitrogen (N)-fertilizer forms in the phytoremediation of Cd through Solanum nigrum L. Two types of N fertilizers (NH4NO3 and urea) were applied to the soil in different ratios (0:0, 100:0, 0:100, and 50:50 of NH4NO3 and urea, individually) along with different Cd levels (0, 25, and 50 mg kg−1). The plants were harvested 70 days after sowing the seeds in pots. Cadmium contamination significantly inhibited the growth of leaves and roots of S. nigrum plants. Cadmium contamination also induced oxidative stress; however, the application of N-fertilizers increased the plant biomass by inhibiting oxidative stress and enhancing antioxidants’ enzymatic activities. The greatest plant growth was observed in the urea-treated plants compared with the NH4NO3-treated plants. In addition, urea-fed plants also accumulated higher Cd concentrations than NH4NO3-fed plants. It is concluded that urea is helpful for better growth of S. nigrum under Cd stress. Thus, an optimum concentration of N-fertilizers might be effective in the phytoremediation of heavy metals through S. nigrum.

Sustainable and cost-effective methods are required to increase the food production and decrease the toxic effects of heavy metals. Most of the agriculture land is contaminated with cadmium (Cd). The present study was designed to minimize the toxic effect of Cd stress (0, 10 and 20 mg kg

Cadmium (Cd) is a highly toxic metal released into the environment through anthropogenic activities. Phytoremediation is a green technology used for the stabilization or remediation of Cd-contaminated soils. Brassica crop species can produce high biomass under a range of climatic and growing conditions, allowing for considerable uptake and accumulation of Cd, depending on species. These crop species can tolerate Cd stress via different mechanisms, including the stimulation of the antioxidant defense system, chelation, compartmentation of Cd into metabolically inactive parts, and accumulation of total amino-acids and osmoprotectants. A higher Cd-stress level, however, overcomes the defense system and may cause oxidative stress in Brassica species due to overproduction of reactive oxygen species and lipid peroxidation. Therefore, numerous approaches have been followed to decrease Cd toxicity in Brassica species, including selection of Cd-tolerant cultivars, the use of inorganic and organic amendments, exogenous application of soil organisms, and employment of plant-growth regulators. Furthermore, the coupling of genetic engineering with cropping may also help to alleviate Cd toxicity in Brassica species. However, several field studies demonstrated contrasting results. This review suggests that the combination of Cd-tolerant Brassica cultivars and the application of soil amendments, along with proper agricultural practices, may be the most efficient means of the soil Cd phytoattenuation. Breeding and selection of Cd-tolerant species, as well as species with higher biomass production, might be needed in the future when aiming to use Brassica species for phytoremediation.

Heavy metal contamination is currently a major environmental concern, as most agricultural land is being polluted from municipal discharge. Among various other pollutants, cadmium (Cd), one of the most harmful heavy metals, enters into the food chain through the irrigation of crops with an industrial effluent. In the present study, a pot experiment was designed to assess the effect of different nitrogen (N)-fertilizer forms in the phytoremediation of Cd through Solanum nigrum L. Two types of N fertilizers (NH4NO3 and urea) were applied to the soil in different ratios (0:0, 100:0, 0:100, and 50:50 of NH4NO3 and urea, individually) along with different Cd levels (0, 25, and 50 mg kg&minus, 1). The plants were harvested 70 days after sowing the seeds in pots. Cadmium contamination significantly inhibited the growth of leaves and roots of S. nigrum plants. Cadmium contamination also induced oxidative stress, however, the application of N-fertilizers increased the plant biomass by inhibiting oxidative stress and enhancing antioxidants&rsquo, enzymatic activities. The greatest plant growth was observed in the urea-treated plants compared with the NH4NO3-treated plants. In addition, urea-fed plants also accumulated higher Cd concentrations than NH4NO3-fed plants. It is concluded that urea is helpful for better growth of S. nigrum under Cd stress. Thus, an optimum concentration of N-fertilizers might be effective in the phytoremediation of heavy metals through S. nigrum.

Silicon (Si) is considered the 2nd most abundant element present in the earth crust. Although Si is not an essential nutrient for plants, it is considered a highly beneficial element that plays an important role in soil–plant interactions, especially under stressful conditions. Plant available sources of Si in soil mainly include plant-derived Si (phytolith Si) and amorphous silica (ASi) with minor parts of microbial and protistic Si. In agricultural soils, phytolith Si is continuously removed due to the harvesting of the crops. Biochar is prepared from slow pyrolysis of organic materials, especially crop residues that are used for various purposes in agricultural soils, such as carbon sequestration, reduction of greenhouse gases, nutrient supply to plants, and minimization of pollutant toxicity to plants. Biochar prepared from Si-accumulator crops, such as rice and wheat straws, may contain higher concentrations of phytolith Si that might be a potential source of available Si for plants. In the present chapter, the possible sources of Si, its effects on crops, and possibility of biochar as a potential plant available Si have been discussed.

The world population has increased drastically. Land uses have changed to meet increased demands for basic requirements such as settlements, industrial production, and food. The amount of fertile land decreases day by day, consequently altering its nutrient status. Existing agricultural land faces the problem of heavy metal toxicity caused by industrialization. Cadmium (Cd) is an extremely toxic heavy metal. Cd toxicity causes oxidative stress and thus the overproduction of reactive oxygen species, electrolyte leakage, and lipid peroxidation. Nutrients essential for plant growth include nitrogen, phosphorus, calcium, sulfur, selenium, silicon, and potassium, and their exogenous application reduces Cd toxicity to a great extent. They can be applied in liquid as well as solid form, mostly as fertilizers. Exogenous application of nutrients reduces Cd accumulation through decreased H2O2 and malondialdehyde levels; improved fresh weight; modified superoxide dismutase, ascorbate peroxidase, catalase, dehydroascorbate reductase, and glutathione reductase activities; improved growth inhibition; increased nitric oxide, pectin, and hemicellulose contents as well as protein and nonprotein thiol levels. These approaches might be helpful in reducing Cd toxicity with the exogenous application of nutrients.

Contamination of soils with cadmium (Cd) is a serious problem worldwide. Rice (Oryza sativa L.) is reported to accumulate relatively higher Cd contents in consumable parts and is considered a main source of Cd toxicity to humans from rice-derived products. The aim of this pot trial was to investigate the effect of foliar-applied iron (Fe) complexed with lysine on growth, photosynthesis, Cd concentration in plants, oxidative stress, and activities of antioxidants of rice in soil contaminated with Cd. Rice seedlings (30-day-old) were transferred to the soil, and after 2 weeks, different concentrations of Fe-lysine (0, 1.5, 3.0, 4.5, 6.0, and 7.5 mg L−1) were applied as a foliar spray once in a week for 4 weeks and plant samples were taken after 10 weeks of growth in the soil under ambient conditions. Foliar supply of Fe-lysine complex significantly enhanced the plant height, dry weights of plants, concentration of chlorophyll, and gas exchange attributes in Cd-stressed rice. Fe-lysine decreased the Cd concentrations in plants while increasing the Fe concentrations in rice seedlings being maximum with Fe-lysine of 6.0 mg L−1. Electrolyte leakage decreased while activities of key antioxidant enzymes increased with Fe-lysine compared to the control. According to the present results, Fe-lysine complex can effectively be used to reduce Cd concentrations in rice and probably in other crop species.

The use of chromium (Cr)-contaminated tannery wastewater for irrigation is a common practice, especially in developing countries like Pakistan. This practice is due to the shortage of good quality irrigation water for crop growth as well as the issue of tannery wastewater disposal. The current study was done to evaluate the effect of citric acid (CA) (0, 1.0, and 2.0 mM) on the growth and Cr uptake by spinach irrigated with different mixtures of tap water and tannery wastewater (100:0, 50:50, and 0:100 tap water to wastewater ratio). Plants were grown for 8 weeks under ambient conditions. Results showed that 50:50% tap water and wastewater increased plant height, dry weights of shoots and roots, total chlorophyll contents, and gas exchange attributes than the plants treated with only tap water or only wastewater. Increasing wastewater ratio increased electrolyte leakage (EL) in plants and enhanced the leaf key antioxidant enzyme activities as well as increased Cr contents. Foliar application of CA increased the plant dry weights, photosynthesis, and enzyme activities, whereas reduced the EL and Cr concentrations in plants than respective treatments without CA application. It can be concluded that 50:50 tap water and wastewater irrigation along with foliar CA application might be an effective strategy for increasing vegetable growth with reduced metal concentrations.