Accumulation Pattern of Heavy Metals in Chromolaena odorata (L.) King & Robins. Grown in Nutrient Solution and Soil

Accumulation pattern of Al, Cd, Fe, Hg, Cr, Cu, Pb, Ni and Zn in Chromolaena odorata plants grown in Hoagland nutrient solution and soil contaminated with known quantities of the above said metals was investigated. Significant variations in the quantity of accumulation as well as distribution among plant parts like root, stem and leaf were shown between the metals. Accumulation of Pb was maximum in the root followed by Fe and Al. Maximum quantity of each metal was accumulated in the root as compared to stem and leaf. Drastic differences in the accumulation pattern of metals between the nutrient solution and soil culture was observed. Comparatively small quantity of metal was accumulated in the plants of soil despite several fold quantity of each metal was given. The results are discussed in terms of BCF, TF, metal specificity as well as detoxification mechanisms

Enhanced phytostabilization of cadmium by a halophyte—<i>Acanthus ilicifolius</i> L.

<p>Heavy metal pollution in mangrove wetlands has become a growing matter of concern as it serves as sink and source for toxic heavy metals including cadmium (Cd). The present study evaluates the phytostabilization potential of a halophyte, <i>Acanthus ilicifolius</i> L., toward Cd under hydroponic culture conditions. Accumulation, translocation, and effects of Cd on the antioxidant system of <i>A. ilicifolius</i> were studied. Results indicated that A. ilicifolius accumulated Cd mainly in roots (96.4%) as compared to stem (1.4%) and leaves (0.6%) and the accumulated Cd is retained in root rather than being translocated to shoots as indicated by TF < 0.26. Moreover, malondialdehyde (MDA) content increased upon Cd treatment, which is further detoxified by the enzymatic and nonenzymatic antioxidant mechanism. Antioxidants like proline, ascorbate, and amino acid recorded an increased accumulation in the Cd-treated plants followed by the upregulation of antioxidant enzymes like superoxide dismutase (SOD), catalase (CAT), guaiacol peroxidase (GPX), and ascorbate peroxidase (APX). Therefore, the rate of sugar accumulation was found to be decreased in plants treated with Cd as compared to the control plants. Thus, having relatively high BCF_root (69.3) and low TF_shoot (0.26) values, <i>A. ilicifolius</i> can be suggested as a potential candidate for phytostabilization of Cd in mangrove wetlands.</p

Synergistic interactions of assorted ameliorating agents to enhance the potential of heavy metal phytoremediation

Abstract Pollution by toxic heavy metals creates a significant impact on the biotic community of the ecosystem. Nowadays, a solution to this problem is an eco-friendly approach like phytoremediation, in which plants are used to ameliorate heavy metals. In addition, various amendments are used to enhance the potential of heavy metal phytoremediation. Symbiotic microorganisms such as phosphate-solubilizing bacteria (PSB), endophytes, mycorrhiza and plant growth-promoting rhizobacteria (PGPR) play a significant role in the improvement of heavy metal phytoremediation potential along with promoting the growth of plants that are grown in contaminated environments. Various chemical chelators (Indole 3-acetic acid, ethylene diamine tetra acetic acid, ethylene glycol tetra acetic acid, ethylenediamine-N, N-disuccinic acid and nitrilotri-acetic acid) and their combined action with other agents also contribute to heavy metal phytoremediation enhancement. With modern techniques, transgenic plants and microorganisms are developed to open up an alternative strategy for phytoremediation. Genomics, proteomics, transcriptomics and metabolomics are widely used novel approaches to develop competent phytoremediators. This review accounts for the synergistic interactions of the ameliorating agent’s role in enhancing heavy metal phytoremediation, intending to highlight the importance of these various approaches in reducing heavy metal pollution

Physio-anatomical modifications and elemental allocation pattern in Acanthus ilicifolius L. subjected to zinc stress.

Physio-anatomical modifications and elemental distribution pattern in Acanthus ilicifolius subjected to Zn stress were analysed in this study. Survival of A. ilicifolius plants under a high concentration of ZnSO4 was compensated by the reduction in the photosynthetic efficacy. Micro and macro-elemental distribution pattern in the root tissues was significantly influenced by heavy metal exposure. Tolerance towards the excess toxic metal ions in the tissue of A. ilicifolius was aided by the modified anatomical features. Moreover, the increased deposition of Zn around the central vasculature of the root confirms the complexation of Zn2+ in the xylem vessels. Metal induced molecular level changes of root and leaf samples indicate the presence of OH, NH2, and CH3 deformation as well as C-O-H and C-O-C stretch. A prominent band corresponding to CH3 deformation, pointing hemicellulose fortification, occurs in the cell walls of the xylem, aiding in Zn localization. The phytostabilisation potential of A. ilicifolius is dependent on the coordinated responses which endow with phenotypic plasticity necessary to cope with Zn toxicity