Hibiscus rosa-sinensis as a potential hyperaccumulator in metal contaminated magnesite mine tailings

Integration of physio-biochemical, biological and molecular approaches to improve heavy metal tolerance in plants

Heavy metal toxicity hinders plant growth and development by inducing oxidative stress, decreasing biomass, impairing photosynthesis, and potentially leading to plant death. The inherent defense mechanisms employed by plants, including metal sequestration into vacuoles, phytochelation, cell wall metal adsorption and an enhanced antioxidant system can be improved via various approaches to mitigate heavy metal toxicity. This review primarily outlines plants direct and indirect responses to HM stress and the tolerance mechanisms by which plants combat the toxic effects of metals and metalloids to understand the effective management of HMs and metalloids in the soil system. Furthermore, this review highlights measures to mitigate metal and metalloid toxicity and improve metal tolerance through various physio-biochemical, biological, and molecular approaches. This review also provides a comprehensive account of all the mitigative approaches by comparing physio-biochemical, biological and molecular approaches. Finally, we compared all the mitigative approaches used in monocotyledonous and dicotyledonous to increase their metal tolerance. Although many studies have compared monocot and dicot plants based on metal toxicity and tolerance effects, comparisons of these mitigative approaches have not been explored.

Energy, Aromatic, and Medicinal Plants' Potential and Prospects for the Remediation of Potentially Toxic Element-Contaminated Agricultural Soils: A Critical Meta-Analysis

A critical meta-analysis of the past decade's investigations was carried out with the aim of assessing the use of plant-based techniques for soil remediation. Potentially toxic element (PTE) contaminated soils were selected since these contaminants are considered hazardous and have long-term effects. Furthermore, energy, aromatic, and medicinal plants were studied as their high-value products seem to be affected by PTEs' existence. Lead (Pb), Cu, Cd, Zn, Cr, Co, Ni, Hg, and As accumulation in different parts of plant species has been investigated using proper indices. Aromatic plants seem to provide high phytoremediation yields. Increasing toxicity levels and the coexistence of many metals enhance the accumulation capacity of aromatic plants, even of toxic Cd. In plants usable as energy sources, antagonistic effects were observed, as the simultaneous presence of Cu and Cd resulted in lower thermic capacity. Finally, in most of the plants studied, it was observed that the phytostabilization technique, i.e., the accumulation of metals mainly in the roots of the plants, was often used, allowing for the aboveground part to be almost completely free of metallic pollutants. Using plants for remediation was proven to be advantageous within a circular economy model. Such a process is a promising solution, both economically and environmentally, since it provides a useful tool for keeping environmental balance and producing safe goods.

Conversion of metal-enriched magnetite mine tailings into suitable soil for vegetation by phytoremediation process with Bougainvillaea glabra under the influence of Thiobacillus ferroxidance

Magnetite mining is a significant contributor to land deterioration as well as HM-based soil contamination. The characteristics of magnetite mine tailing were examined in the present study, in addition to the positive and sustainable restoration strategy with Bougainvillaea glabra under the influence of Thiobacillus ferroxidance. The traits of test soil analysis findings demonstrated that the majority of the parameters exceeded the allowable limits (For instance: HMs such as Cr, Cu, Zn, Pb, Fe, and Co were found to be 208 ± 2.3, 131.43 ± 1.6, 185.41 ± 3.3, 312 ± 5.11, 956 ± 5.3, and 26.89 ± 2.43 mg kg-1 respectively). T. ferroxidance exhibited impressive HMs tolerance for as much as 800 g mL-1 concentrations of Cr, Cu, Zn, Pb, Fe, and Co. To prevent HMs toxic effects, the HMs contents in test soil were decreased by diluting with normal soil in the ratios of Ex-3 and Ex-2. A typical greenhouse study was carried out to assess the phytoremediation ability of B. glabra across six setups for experiments (Ex-1 to Ex-6). According to the findings of this research, the HMs tolerant T. ferroxidance from Ex-3 and Ex-2 had an outstanding impact on the growth, biomolecules level (such as chlorophylls: 65.84 & 41.1 mg g-1, proteins: 165.1 & 151.1 mg g-1, as well as carbohydrates: 227.4 & 159.3 mg g-1) as well as phytoremediation potential of B. glabra on magnetite mine soil. These findings indicated that a mixture of B. glabra as well as T. ferroxidance might serve as a valuable sustainable agent for removing HMs from contaminated soil.