Role of beneficial elements signaling and metabolic performance in plants under heavy metal stress

Abstract

A significant increase in bioaccumulation and biomagnification of heavy metals (HMs) in the environment has become a predicament for all living organisms including plants. At toxic concentrations, HMs can interact with a variety of essential cellular molecules that cause an excessive increase in reactive oxygen species. As a result, plants would suffer from severe morphological, cytological, metabolic, and physiological abnormalities. To combat the HM toxicity, plants are provided with a variety of defense mechanisms and they are in command of preserving the homeostasis of the vital metals. Ionome includes the role of beneficial elements such as nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), sulfur (S), and magnesium (Mg) also trace elements such as iron (Fe), copper (Cu), cobalt (Co), molybdenum (Mo), manganese (Mn), and zinc (Zn) in reducing the HM toxicity. Initially, only 19 elements were chosen for basic metabolism including macronutrients, such as C, O, H, Mg, S, N, Ca, P, and K, and micronutrients, such as Cu, Zn, Mn, Fe, Mo, B, Ni, Co, Cl, and B. Additionally, Si is also regarded as a helpful element which is used to maintain the structural integrity of the cells. Both macro- and micronutrients are crucial for the physiological and biochemical functions of plants, including the synthesis of chlorophyll, DNA and protein, photosynthesis, DNA and protein modifications, redox reactions in chloroplasts and mitochondria, sugar metabolism, and nitrogen fixation. Apart from these, they also play an important role in mitigating HM toxicity. This chapter is intending to summarize role of beneficial elements signaling and metabolic performance in plants under HM toxicity.