Effect of Heavy Metals on Plant Growth: An Overview

2020 ◽  
pp. 79-101
Author(s):  
Deepika Goyal ◽  
Arti Yadav ◽  
Mrinalini Prasad ◽  
Teg Bahadur Singh ◽  
Preksha Shrivastav ◽  
...  
Keyword(s):  
2021 ◽  
Vol 13 (5) ◽  
pp. 2432
Author(s):  
Anna Makarova ◽  
Elena Nikulina ◽  
Tatiana Avdeenkova ◽  
Ksenia Pishaeva

Heavy metals are among the most widespread pollutants in soil. Phytoextraction technology is used to solve the problem of multi-metal-contaminated soil. The efficiency of this process can be increased by introducing various amendments. A soil amendment is any material added to a soil to improve its physical properties, such as water retention, permeability, water infiltration, drainage, aeration, and structure. Some chemical amendments for enhanced phytoextraction, such as amino polycarboxylates chelators, can be hazardous to the environment and perform poorly at pH > 8. The effect of the potassium salt of hydroxyethylidene diphosphonic acid (K2HEDP), plant growth regulators (PGRs), and iron chelate alone and in combination on the phytoextraction by Trifolium repens L. seedlings of Cd, Ni, and Cu was studied in this work. K2HEDP works in a wider pH range. The results of this study confirmed that amino polycarboxylate chelators, with the sodium salt of ethylene diamine tetraacetic acid (Na2EDTA) as an example, have a pronounced negative effect on the growth and development (organ mass) of Trifolium repens L. seedlings. K2HEDP, proposed by the authors instead of Na2EDTA, produced a pronounced positive effect on plant growth and development, which was further enhanced by the use of PGRs and with iron chelates. However, it should be noted that K2HEDP showed significantly lower efficiency in trials on the Trifolium repens L. seedlings. The highest was the efficiency of K2HEDP with PGRs and iron chelates for the phytoextraction of Cd.


2021 ◽  
Vol 11 (9) ◽  
pp. 4160
Author(s):  
Farheen Nazli ◽  
Xiukang Wang ◽  
Maqshoof Ahmad ◽  
Azhar Hussain ◽  
Bushra ◽  
...  

Untreated wastewater used for irrigating crops is the major source of toxic heavy metals and other pollutants in soils. These heavy metals affect plant growth and deteriorate the quality of edible parts of growing plants. Phytohormone (IAA) and exopolysaccharides (EPS) producing plant growth-promoting rhizobacteria can reduce the toxicity of metals by stabilizing them in soil. The present experiment was conducted to evaluate the IAA and EPS-producing rhizobacterial strains for improving growth, physiology, and antioxidant activity of Brassica juncea (L.) under Cd-stress. Results showed that Cd-stress significantly decreased the growth and physiological parameters of mustard plants. Inoculation with Cd-tolerant, IAA and EPS-producing rhizobacterial strains, however, significantly retrieved the inhibitory effects of Cd-stress on mustard growth, and physiology by up regulating antioxidant enzyme activities. Higher Cd accumulation and proline content was observed in the roots and shoot tissues upon Cd-stress in mustard plants while reduced proline and Cd accumulation was recorded upon rhizobacterial strains inoculation. Maximum decrease in proline contents (12.4%) and Cd concentration in root (26.9%) and shoot (29%) in comparison to control plants was observed due to inoculation with Bacillus safensis strain FN13. The activity of antioxidant enzymes was increased due to Cd-stress; however, the inoculation with Cd-tolerant, IAA-producing rhizobacterial strains showed a non-significant impact in the case of the activity of superoxide dismutase (SOD), peroxidase (POX) and catalase (CAT) in Brassica juncea (L.) plants under Cd-stress. Overall, Bacillus safensis strain FN13 was the most effective strain in improving the Brassica juncea (L.) growth and physiology under Cd-stress. It can be concluded, as the strain FN13 is a potential phytostabilizing biofertilizer for heavy metal contaminated soils, that it can be recommended to induce Cd-stress tolerance in crop plants.


2020 ◽  
Vol 8 (2) ◽  
pp. 153 ◽  
Author(s):  
Francesca Luziatelli ◽  
Anna Grazia Ficca ◽  
Mariateresa Cardarelli ◽  
Francesca Melini ◽  
Andrea Cavalieri ◽  
...  

Distinctive strains of Pantoea are used as soil inoculants for their ability to promote plant growth. Pantoea agglomerans strain C1, previously isolated from the phyllosphere of lettuce, can produce indole-3-acetic acid (IAA), solubilize phosphate, and inhibit plant pathogens, such as Erwinia amylovora. In this paper, the complete genome sequence of strain C1 is reported. In addition, experimental evidence is provided on how the strain tolerates arsenate As (V) up to 100 mM, and on how secreted metabolites like IAA and siderophores act as biostimulants in tomato cuttings. The strain has a circular chromosome and two prophages for a total genome of 4,846,925-bp, with a DNA G+C content of 55.2%. Genes related to plant growth promotion and biocontrol activity, such as those associated with IAA and spermidine synthesis, solubilization of inorganic phosphate, acquisition of ferrous iron, and production of volatile organic compounds, siderophores and GABA, were found in the genome of strain C1. Genome analysis also provided better understanding of the mechanisms underlying strain resistance to multiple toxic heavy metals and transmission of these genes by horizontal gene transfer. Findings suggested that strain C1 exhibits high biotechnological potential as plant growth-promoting bacterium in heavy metal polluted soils.


2021 ◽  
Vol 3 ◽  
Author(s):  
Subhrangshu Mandal ◽  
Kunal Kumar Saha ◽  
Narayan Chandra Mandal

Over the past few decades, the massive increase in anthropogenic activity and industrialization processes has increased new pollutants in the environment. The effects of such toxic components (heavy metals, pesticides, etc.) in our ecosystem vary significantly and are of significant public health and economic concern. Because of this, environmental consciousness is increasing amongst consumers and industrialists, and legal constraints on emissions are becoming progressively stricter; for the ultimate aim is to achieve cost-effective emission control. Fortunately, certain taxonomically and phylogenetically diverse microorganisms (e.g., sulfur oxidizing/reducing bacteria) are endowed with the capability to remediate such undesired components from diverse habitats and have diverse plant-growth-promoting abilities (auxin and siderophore production, phosphate solubilization, etc.). However, the quirk of fate for pollutant and plant-growth-promoting microbiome research is that, even with an early start, genetic knowledge on these systems is still considered to be in its infancy due to the unavailability of in-depth functional genomics and population dynamics data from various ecosystems. This knowledge gap can be breached if we have adequate information concerning their genetic make-up, so that we can use them in a targeted manner or with considerable operational flexibility in the agricultural sector. Amended understanding regarding the genetic basis of potential microbes involved in such processes has led to the establishment of novel or advanced bioremediation technologies (such as the detoxification efficiency of heavy metals), which will further our understanding of the genomic/genetic landscape in these potential organisms. Our review aimed to unravel the hidden genomic basis and eco-physiological properties of such potent bacteria and their interaction with plants from various ecosystems.


2021 ◽  
Vol 16 (AAEBSSD) ◽  
pp. 77-85
Author(s):  
Sridevi Tallapragada ◽  
Rajesh Lather ◽  
Vandana ◽  
Gurnam Singh

Phytoremediation is the plant-based technology that has emerged as a novel cost effective and ecofriendly technology in which green plants are used for extraction, sequestration and/or detoxification of the pollutants. Plants possess the natural ability to degrade heavy metals and this property of plants to detoxify contaminants can be used by genetic engineering approach. Currently, the quality of soil and water has degraded considerably due heavy metal accumulation through discharge of industrial, agricultural and domestic waste. Heavy metal pollution is a global concern and a major health threat worldwide. They are toxic, and can damage living organisms even at low concentrations and tend to accumulate in the food chain. The most common heavy metal contaminants are: As, Cd, Cr, Cu, Hg, Pb and Zn. High levels of metals in soil can be phytotoxic, leading to poor plant growth and soil cover due to metal toxicity and can lead to metal mobilization in runoff water and thus have a negative impact on the whole ecosystem. Phytoremediation is a green strategy that uses hyperaccumulator plants and their rhizospheric micro-organisms to stabilize, transfer or degrade pollutants in soil, water and environment. Mechanisms used to remediate contaminated soil includes phytoextraction, phytostabilization, phytotransformation, phytostimulation, phytovolatilization and rhizofiltration. Traditional phytoremediation method presents some limitations regarding their applications at large scale, so the application of genetic engineering approaches such as transgenic transformation, nanoparticles addition and phytoremediation assisted with phytohormones, plant growth-promoting bacteria and Arbuscular mycorrhizal fungi (AMF) inoculation has been applied to ameliorate the efficacy of plants for heavy metals decontamination. In this review, some recent innovative technologies for improving phytoremediation and heavy metals toxicity and their depollution procedures are highlighted.


2020 ◽  
Vol 21 (5) ◽  
Author(s):  
Nuril Hidayati ◽  
Dwi Setyo Rini

Abstract. Hidayati N, Rini DS. 2020. Assessment of plants as lead and cadmium accumulators for phytoremediation of contaminated rice field. Biodiversitas 21: 1928-1934. Heavy metals contamination in agricultural land becoming a serious problem since this causes declining in agriculture production and quality and thus food safety. Meanwhile, conventional efforts for remediation of the contaminated agricultural lands have not been widely implemented due to high-cost constraints. A low-cost technology that can be applied in contaminated sites is phytoremediation. This technique is based on the fact that plants have the ability to extract and accumulate heavy metals. This research aimed to study the potentials of some plant species as accumulators for phytoremediation in rice fields contaminated by heavy metals of lead (Pb) and cadmium (Cd). Six selected accumulator plant species, namely Colocasia sp., Ipomoea fistulosa Mart. ex Choisy, Eichhornia crassipes (Mart.) Solms, Hymenachne amplexicaulis (Rudge) Nees), Saccharum spontaneum L., and Acorus calamus L., were tested in in-situ field to identify the performance of the plants as accumulators for Pb and Cd. Parameters observed were plant growth and biomass production, and the accumulation of Pb and Cd in plants which is formulated as: bioconcentration factor (BCF) to indicate concentration ratio of metal in plant to soil, and translocation factor (TF) to indicate metal transportation ratio of shoot to root. The results showed that plants with the highest growth rate under contaminated conditions were E. crassipes, A. calamus, and H. amplexicaulis. The highest value of BCF for Pb accumulation was recorded in the shoot of H. amplexicaulis and E. crassipes and in the root of H. amplexicaulis and A. calamus, whereas the highest value of TF for Pb was observed in E. crassipes, S. spontaneum, and H. amplexicaulis. Meanwhile, the highest value of BCF for Cd in the shoot and in the root was observed in Colocasia sp and H. amplexicaulis whereas the highest value of TF for Cd was identified in A calamus and Colocasia sp. With regards to the performance of plant growth, biomass production, and accumulation of Pb and Cd, it is suggested that three plant species, namely E. crassipes, A. calamus, and H. amplexicaulis are considered as potential Pb and Cd accumulators for phytoremediation of contaminated rice fields. Our findings suggest that some plants can produce high biomass and absorb high contaminants while other plants cannot, implying that plants respond differently to different environmental conditions. Therefore continuous research is required to obtain the best plant species for phytoremediation.


2012 ◽  
Vol 518-523 ◽  
pp. 5040-5046 ◽  
Author(s):  
Li Di Gao ◽  
Naoki Kano ◽  
Yuichi Sato ◽  
Shuang Zhang ◽  
Hiroshi Imaizumi

Effect of EDTA and EDDS on phytoremediation of Pb- and Zn- contaminated soil by Brassica Juncea was investigated in this work. Especially, the effect of the kind and the method of adding chelating agent was investigated during the plant growth. Plants were grown in an environmental control system. The biomass of the whole plant was weighed, and the uptake of Pb and Zn in shoot and root were determined using ICP-AES. Consequently, the following matters have been obtained: (1) Both EDTA and EDDS significantly enhanced the translocation of metals (Pb and Zn) in soil from root to shoot. Furthermore, the two chelating agents resulted in a sharply biomass loss for more than 30% of the control. As a result, the total uptake amount of metals by Brassica Juncea was decreased (except the uptake of Pb with the addition of 3.0 mmol•kg-1 EDTA). (2) EDDS showed the higher inhibition for the growth of Brassica Juncea than EDTA. (3) The method for adding EDTA and EDDS at several times separately did not necessarily increase the uptake of heavy metals.


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