Cadmium Phytotoxicity, Tolerance, and Advanced Remediation Approaches in Agricultural Soils; A Comprehensive Review

Abstract

Cadmium (Cd) is a major environmental contaminant due to its widespread industrial use. Cd contamination of soil and water is rather classical but has emerged as a recent problem. Cd toxicity causes a range of damages to plants ranging from germination to yield suppression. Plant physiological functions, i.e., water interactions, essential mineral uptake, and photosynthesis, are also harmed by Cd. Plants have also shown metabolic changes because of Cd exposure either as direct impact on enzymes or other metabolites, or because of its propensity to produce reactive oxygen species, which can induce oxidative stress. In recent years, there has been increased interest in the potential of plants with ability to accumulate or stabilize Cd compounds for bioremediation of Cd pollution. Here, we critically review the chemistry of Cd and its dynamics in soil and the rhizosphere, toxic effects on plant growth, and yield formation. To conserve the environment and resources, chemical/biological remediation processes for Cd and their efficacy have been summarized in this review. Modulation of plant growth regulators such as cytokinins, ethylene, gibberellins, auxins, abscisic acid, polyamines, jasmonic acid, brassinosteroids, and nitric oxide has been highlighted. Development of plant genotypes with restricted Cd uptake and reduced accumulation in edible portions by conventional and marker-assisted breeding are also presented. In this regard, use of molecular techniques including identification of QTLs, CRISPR/Cas9, and functional genomics to enhance the adverse impacts of Cd in plants may be quite helpful. The review’s results should aid in the development of novel and suitable solutions for limiting Cd bioavailability and toxicity, as well as the long-term management of Cd-polluted soils, therefore reducing environmental and human health hazards.

Influence of biochar and microorganism co-application on stabilization of cadmium (Cd) and improved maize growth in Cd-contaminated soil

“…Cadmium causes chlorophyll destruction, restricts nutrient uptake, and reduces photosynthetic activity resulting in significant reduction in plant growth (Abbas et al, 2018 ; Zhang et al, 2019 ; Farooq et al, 2020 ). Reduction in the uptake of the essential nutrients, physiological and morphological traits of the plant is regulated by Cd which can be transferred to the aboveground parts of the plant by replacing essential ions i.e., Ca due to having the same chemical behavior, ionic radius, and charge (Haider et al, 2021 ; Zulfiqar et al, 2022 ). This may directly hamper metabolic processes, resulting in growth inhibition, and yield reduction (Abbas et al, 2017 ; El-Naggar et al, 2020 ).…”

“…Biochar is a renewable porous carbonaceous resource loaded with phosphate, nitrate, and ammonium that enhances the fertility status of agricultural soil (Rehman et al, 2016 ). Biochar can also be utilized as a source of nutrients to improve the fertility status of soil in various agronomic crops i.e., rice ( Oryza sativa L.), wheat ( Triticum aestivum L.), maize ( Zea mays L.), alfalfa ( Medicago sativa L.), and soybean ( Glycine max L.), due to the inclusion of soluble nutrients and the labile fraction of biochar comprising organically bound nutrients for mineralization (Sabae et al, 2006 ; Abbas et al, 2017 ; Zulfiqar et al, 2022 ).…”

“…Cadmium contamination of restricts the nutrients uptake, inhibits the carbon dioxide fixation, causes chlorophyll destruction resulting in reduction in net rate of photosynthesis and overall plant productivity (Gallego et al, 2012 ; Haider et al, 2021 ). Cadmium toxicity results in over-production of reactive oxygen species (ROS) causing damages to biological membranes and other sub-cellular organelles Zhao et al, 2013 ; Haider et al, 2022a ; Zulfiqar et al, 2022 . Therefore, developing effective strategies to mitigate the adverse effects of Cd on the ecosystem and soil rhizosphere is one of the major challenges.…”

A Comparative Photographic Review on Higher Plants and Macro-Fungi: A Soil Restoration for Sustainable Production of Food and Energy

“…In the case of plants, remediation strategies depend on the type of pollutants (organic or inorganic) and the concentration. These strategies include bio-electrokinetic remediation [142], physicochemical remediation methods (such as chelate-assisted phytoextraction), phytohormones or plant growth regulators (e.g., auxins, abscisic acid, brassinosteroids, cytokinins, ethylene, gibberellins, jasmonic acid, polyamines, and nitric oxide), microbe-assisted remediation, plant growth-promoting rhizobacteria, inorganic/organic amendments such as biochar, compost, manure for immobilization pollutants in soils, as well as genetic strategies [143].…”

Quantitative Succinyl-Proteome Profiling of Turnip (Brassica rapa var. rapa) in Response to Cadmium Stress

“…Cadmium (Cd), a global pollutant that comes from both anthropogenic (e.g., industrial waste, atmospheric deposition, sewage water, and chemical fertilizers) and natural sources (e.g., parent material, volcanos, fossil fuels) [ 1 , 2 ], is one of the most toxic heavy metals to living organisms [ 3 , 4 ]. In plants, Cd toxicity inhibits carbon fixation, reduces chlorophyll synthesis and photosynthetic activity, causes osmotic stress, and induces overproduction of reactive oxygen species (ROS) to damage the plant membranes and the destruction of the cell organelles [ 3 ]. Cd also has harmful effects on the uptake and transportation of mineral elements, resulting in growth inhibition [ 5 ].…”