Heavy metal stress and responses in plants

N. -H. Ghori, T. Ghori, M. Q. Hayat, S. R. Imadi, A. Gul, V. Altay, M. Ozturk

Research output: Contribution to journalReview article

20 Citations (Scopus)

Abstract

Heavy metals such as Fe, Mn, Cu, Ni, Co, Cd, Zn, Hg and arsenic are for long being accumulated in soils through industrial waste and sewage disposal. Although some of these metals are essential micronutrients responsible for many regular processes in plants, their excess, however, can have detrimental effects and can directly influence the plant growth, metabolism, physiology and senescence. Plants have different mechanisms to fight stress, and they are responsible to maintain homeostasis of essential metals required by plants. These mechanisms also focus on prevention of plants exposure to heavy metals present in the soil or providing tolerance to the plant by detoxifying the metals. Other mechanisms are specific and are initiated when the respective stress is encountered. The first line of defense provided by a plant is to reduce the uptake of metals when stimulated with toxicity of heavy metals and includes the help offered by cellular and root exudates that restricts metals from entering the cell. Many plants have exclusive mechanisms for individual metal ions and are involved in sequestering these ions in compartments avoiding their exposure to sensitive components of the cells. As a second line of defense, other mechanisms for detoxification of these metals are introduced that chelates, transports, sequesters and detoxifies these metal ions in the plant's vacuole. During the time of metal toxicity, oxidative stress is pronounced in the cells and production of stress-related proteins and hormones, antioxidants, signaling molecules including heat-shock proteins synthesis is initiated.

Original languageEnglish
Pages (from-to)1807-1828
Number of pages22
JournalInternational Journal of Environmental Science and Technology
Volume16
Issue number3
DOIs
Publication statusPublished - Mar 2019

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