Interactive effects of cadmium and copper on metal accumulation, oxidative stress, and mineral composition in Brassica napus

Abstract

Heavy metals' frequent occurrence and toxicity caused considerable concerns in assessing the interactive effects of metals on exposed plants. Therefore, a hydroponic study was conducted to assess the growth response and physio-chemical changes in Brassica napus plants under single and combined stress of two environmentally alarming metals (Cd and Cu). Results showed that 15-day metal exposure to different metal concentrations (0, 50, 200 lM) significantly enhanced Cd accumulation, while lesser extent of Cu was observed in plant tissues. Nonetheless, Cu caused more pronounced oxidative damages and plant growth retardation. Both metals showed similar trend of changes in mineral composition, although Cu proved more damaging effect on K and Mn contents, and Cd on Zn contents. In combined treatments, Cd stimulated Cu uptake, notably at low concentration, while its own uptake was restricted by the presence of Cu. At either level of concentration, combined stress of these metals exacerbated plant growth inhibition and caused further oxidative damages compared to their individual stress. However, metals synergistic effects occurred only in conditions where Cu uptake was enhanced by Cd. A greater synergistic effect was observed in sensitive cultivar Zheda 622 as compared to the tolerant cultivar ZS 758. As to mineral composition, no metals synergistic effects were noted. This study highlighted the ecotoxicological significance of Cd-led Cu uptake in B. napus, which was assumed to drive metals' synergistic toxicity, and showed that the relationship between Cd-led Cu uptake and plant growth responses could vary with respect to cultivar.

Ecotoxicological and Interactive Effects of Copper and Chromium on Physiochemical, Ultrastructural, and Molecular Profiling in Brassica napus L.

“…However, excess concentration of these metals can affect the plant growth as we found in this study. Earlier, Mwamba et al [ 29 ] and Gill et al [ 14 ] found similar results of growth retardation in B. napus plants under Cu and Cr stress conditions, respectively. Here, we also studied the combined effect of Cu and Cr stress on the growth and physiology of B. napus plants and found that a combined application of Cu+Cr proved to be more toxic than Cr followed by Cu alone treatments in both cultivars.…”

Beryllium Stress-Induced Modifications in Antioxidant Machinery and Plant Ultrastructure in the Seedlings of Black and Yellow Seeded Oilseed Rape

“…Be-induced deleterious effects were also evident even at the lowest dose (100 μ M), except for shoot height and stem fresh weight in ZS 758, as well as root fresh weight in both ZS 758 and Zheda 622. In recent studies, we reported a differing level of metal tolerance ability of cultivars ZS 758 and Zheda 622 under Cr [ 6 ], Cu, and Cd [ 41 ] stress. However, in this study, a relatively less difference was observed in the sensitivity and tolerance ability of these cultivars against Be stress.…”

The Response of Duckweed (Lemna minor L.) Roots to Cd and Its Chemical Forms

“…Metal phytotoxicity is considered to induce OS [45,46]. Scandalios [47] found that metals disturbed the normal balance between ROS and antioxidants in all aerobic cells, and a recently conducted study reported that increased antioxidant enzymatic activity has the capability of reducing OS for plants [45].…”