Influence of High and Low Levels of Plant-Beneficial Heavy Metal Ions on Plant Growth and Development

Abstract

Heavy metals (HMs) exists in the environment in both forms as essential and non-essential. These HM ions enter in soil biota from various sources like natural and anthropogenic. Essential HMs such as cobalt (Co), copper (Cu), iron (Fe), manganese (Mn), molybdenum (Mo), nickel (Ni), and zinc (Zn) plays a beneficial role in plant growth and development. At optimum level these beneficial elements improves the plant's nutritional level and also several mechanisms essential for the normal growth and better yield of plants. The range of their optimality for land plants is varied. Plant uptake heavy metals as a soluble component or solubilized them by root exudates. While their presence in excess become toxic for plants that switches the plant's ability to uptake and accumulate other non-essential elements. The increased amount of HMs within the plant tissue displays direct and indirect toxic impacts. Such direct effects are the generation of oxidative stress which further aggravates inhibition of cytoplasmic enzymes and damage to cell structures. Although, indirect possession is the substitution of essential nutrients at plant's cation exchange sites. These ions readily influence role of various enzymes and proteins, arrest metabolism, and reveal phytotoxicity. On account of recent advancements on beneficial HMs ions Co, Cu, Fe, Mn, Mo, Ni, and Zn in soil-plant system, the present paper: overview the sources of HMs in soils and their uptake and transportation mechanism, here we have discussed the role of metal transporters in transporting the essential metal ions from soil to plants. The role played by Co, Cu, Fe, Mn, Mo, Ni, and Zn at both low and high level on the plant growth and development and the mechanism to alleviate metal toxicity at high level have been also discussed. At the end, on concluding the article we have also discussed the future perspective in respect to beneficial HM ions interaction with plant at both levels.

Fertilizer potential of liquid product from hydrothermal treatment of swine manure

“…and Mg, while Al and Cu in the liquid products were found to decrease when compared with those in raw manure (Table 1). Although the concentrations of Fe and Zn increased to some extent after HTT, only 0.78 and 1.33 mg/L were detected in L150-60, respectively, which are much lower than the reported limit values that inhibit plant growth and the national effluent standards in Japan (Arif et al, 2016;Ko et al, 2008; MOE, 2015).…”

Differential Aquaporin Response to Distinct Effects of Two Zn Concentrations after Foliar Application in Pak Choi (Brassica rapa L.) Plants

“…In the long-term Zn experiment, no changes were observed in L 0 , Gs or E in plants treated with the low Zn concentration, but growth was correlated to an enhanced photosynthetic rate (A) at the optimal Zn (25 µM) dose. It has been previously reported that photosynthesis, carbonic anhydrase activity and chlorophyll concentrations were correlated with Zn nutrition at low levels [51,52]. However, at high Zn concentration a reduced stomatal conductance was in consonance with L 0 reductions and a photosynthetic rate decrease in pak choi.…”

Ecological Potential of Plants for Phytoremediation and Ecorestoration of Fly Ash Deposits and Mine Wastes

“…Transport of metal(loid) ions from roots to leaves is performed via membrane transporters, amino acids and/or organic acids (Jabeen et al, 2009). The maintenance of metal-ion homeostasis and plant tolerance in plants is enabled by some families of transporters in roots and leaves: a) influx transporters: ZIP/IRT family of proteins (zinc-iron regulated protein permease) and NRAMP protein (natural resistance-associated macrophage protein); b) efflux transporters: HM-ATPase, CDF (cation diffusion facilitator), CAX (cation exchanger) and ABC (ATPbinding cassette transporters) (Yang et al, 2005;Arif et al, 2016;Castro et al, 2018) (Figures 3B,C). Plant tolerance to deficiency or toxicity of metal(loid)s can be achieved by excluding the element from further course of transport or its accumulation in plant cells (Baker, 1987).…”