Biochemical changes and adaptive strategies of plants under heavy metal stress

By R. Solanki, R. Dhankhar. Biologia, 2011

127 citations recorded by the source corpus.

Heavy metal contamination of soil, aqueous waste stream and ground water causes major environmental and human health problems. Heavy metals are major environmental pollutants when they are present in high concentration in soil and show potential toxic effects on growth and development in plants. Due to unabated, indiscriminate and uncontrolled discharge of hazardous chemicals including heavy metals into the environment, plant continuously have to face various environmental constraints. In plants, seed germination is the first exchange interface with the surrounding medium and has been considered as highly sensitive to environmental changes. One of the crucial events during seed germination entails mobilization of seed reserves which is indispensable for the growth of embryonic axis. But, metabolic alterations by heavy metal exposure are known to depress the mobilization and utilization of reserve food by affecting the activity of hydrolytic enzymes. Some plants possess a range of potential mechanisms that may be involved in the detoxification of heavy metals by which they manage to survive under metal stress. High tolerance to heavy metal toxicity could rely either on reduced uptake or increase planned internal sequestration which is manifested by an interaction between a genotype and its environment. Such mechanism involves the binding of heavy metals to cell wall, immobilization, exclusion of the plasma membrane, efflux of these toxic metal ions, reduction of heavy metal transport, compartmentalization and metal chelation by tonoplast located transporters and expression of more general stress response mechanisms such as stress proteins. It is important to understand the toxicity response of plant to heavy metals so that we can utilize appropriate plant species in the rehabilitation of contaminated areas. Therefore, in the present review attempts have been made to evaluate the effects of increasing level of heavy metal in soils on the key behavior of hydrolytic and nitrogen assimilation enzymes. Additionally, it also provides a broad overview of the strategies adopted by plants against heavy metal stress.

Subfields: Plant Science

View Paper: https://www.semanticscholar.org/paper/5bbadff2c4b7b915f1aabafccd2bab0fd343e64c

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Citations in the corpus

• Alleviation of nickel toxicity in finger millet (Eleusine coracana L.) germinating seedlings by exogenous application of salicylic acid and nitric oxide (2017, background): “Their contamination of the environment threatens the health of vegetation, wildlife, and human beings [3].”
• Coping Mechanisms of Plants to Metal Contaminated Soil (2013, background): “The southern genotype (Poli) was more tolerant than the northern genotype (58-861).”
• Microbial and Plant-Assisted Bioremediation of Heavy Metal Polluted Environments: A Review (2017, background): “Defense mechanisms used by plants include: production of the enzyme phytochelatin synthase that readily binds to heavy metals at lethal levels [89,147,148], production of metallothioneins [89,149] and production of proline that acts as a compatible and metabolic osmolyte, a component of cell walls, ”
• A Review on Practical Application and Potentials of Phytohormone-Producing Plant Growth-Promoting Rhizobacteria for Inducing Heavy Metal Tolerance in Crops (2020, background): “Exploitation of these mechanisms and production of aforementioned biomolecules in response to heavy metal stress depends on plant species, the genotype, and the level of metal tolerance of these crop plants [97].”
• Heavy metal detoxification and tolerance mechanisms in plants: Implications for phytoremediation (2016, background): “378 Elevated levels of Fe, Cu, Zn and Pb have been observed in cell walls of Minuartiaverna sp. 379 Hercynica growing on mine dumps (Solanki and Dhankhar 2011; Neumann et al. 1997).”
• Heavy Metal Stress and Some Mechanisms of Plant Defense Response (2015, background): “Exploitation and upregulation of any of these mechanisms and biomolecules may depend on plant species, the level of their metal tolerance [150], plant growth stage, and metal type.”