Nitrogen and Protein Metabolism in Young Pea Plants as Affected by Different Concentrations of Nickel, Cadmium, Lead, and Molybdenum

Abstract

A comparative study was carried out on the effect of molybdenum (Mo), nickel (Ni), cadmium (Cd), and lead (Pb) using concentrations of 1610 À 7 , 1610 À 5 , and 1610 À 3 mol dm À 3 , on the metabolism of nitrogen and proteins in young pea plants (Pisum sativum L.`NS Lim'). The highest concentrations of the investigated metals were noted to suppress the development of the aboveground parts and roots. The smallest inhibiting effect was observed in the presence of Ni, which at lowest concentration produced a stimulating effect; Pb and Cd had a similar effect. The most pronounced inhibition was caused by Mo, which decreased the growth of the roots and aboveground parts by 50% and 35%, respectively. An increase in concentration of heavy metals in the medium resulted in their increased JOURNAL accumulation in both the plant roots and aboveground parts. The largest accumulation in the aboveground parts was observed for Ni and Mo, followed by Cd, and least for Pb. Nitrate and protein metabolism decreased according to the order of Cd b Pb b Ni b Mo. However, when expressed per amount of heavy metal accumulated in particular plant parts, toxicity was in the order of Pb b Cd b Ni b Mo.

The effect of lead on the phytochemistry of Tithonia diversifolia exposed to roadside automotive pollution or grown in pots of Pb-supplemented soil

“…Diverse biochemical changes in green plants in response to Pb have been reported by several authors: decreases in chlorophyll content (Ewais, 1997;Xiong, 1997;Kastori et al, 1998;Fargasová, 2001), carotenoids (Fargasová, 2001), proteins (Kevresan et al, 2001), nitrate reductase activity Kevresan et al, 2001), lamina and mesophyll thickness, epidermal cell size and diameter of vessels (Kovacevic et al, 1999); increases in chlorophyll a/b ratio (Fargasová, 2001) and concentration of phenols (Lummerzheim et al, 1995;Lavid et al, 2001 a, b). In the presence of other metals, such as Al, Cu and Cd, lipid peroxidation has been found to increase (Cakmark and Horst, 1991;Gallego et al, 1999;Pereira et al, 1999;Baryla et al, 2000;Hartley-Whitaker et al, 2001;Sandalio et al, 2001;Shah et al, 2001).…”

Influence of Cd and Ni on Content of N, P, K, Nitrates and Activity of Nitrate Reductase in Clones ofSalix Spp.

“…Increased amount of nitrate in the cell induces the gene encoding nitrate reductase transcription, resulting in increased activity of the enzyme (23). One of the main causes of reduced nitrate reductase activity is the restricted availability of nitrate and nitrogen from heavy metal toxicity (13,21,24). Treatment with Ni clearly demonstrate the toxic effect on nitrogen assimilation.…”

“…However, an increase of P in roots influenced by Ni, indicates to posible inhibiting effect of nickel on P translocation, whereas Cd influence inhibited the uptake of P by root cells. Nickel caused diverse variation of K content, which in most cases decreased ( (12,13,14,17). Root content of K in investigated willow genotypes of control plants and plants influenced by Cd and Ni and was lower compared to leaf K content.…”

“…Decrease of phosphorus content in investigated willows exposed to elevated concentrations of Cd and Ni determined in leaves, was in specific relation to genotype, with only few exceptions. Decrease of phosphorus in plants influenced by heavy metals is usually expected (12,13,17). However, some researchers report an increase in P content in plants influenced by Cd and Ni, depending on the plant species and ecological conditions (16,25).…”

The analysis of mutation variability of winter wheat under soil contamination with heavy metals of industrial discharges

“…Their entry into the plants is accompanied by the damage of ultra structure and functioning of cell organels, changes in cell metabolism, growth and development depression, productivity decrease. One of the main mechanisms of heavy metal toxic effect is their interaction with SH-groups of proteins, which leads to the change of macromolecule conformation, enzyme inactivation, damage of membrane structure as well as tylakoidal membranes of chloroplasts, and this can be the reason for expression deregulation of chloroplast genes, and as a result, the decrease of rate of photosynthesis [8][9][10][11][12][13]. In addition to direct toxic effect of heavy metals, occurrence of physiological and functional and morphological anomalies, increase of general disease incidence, there are some remote impacts which concern the major functions of living systems -reproduction and productivity, generative characteristics and mortality.…”