Copper‐induced stress in Solanum nigrum L. and antioxidant defense system responses

Abstract

Solanum nigrum L. plants were exposed for 28 days to 100 and 200 μmol/L copper (Cu) in a hydroponic system to analyze the antioxidant defense response. A dose‐dependent reduction in growth (fresh mass of root and shoot, shoot height, and root elongation) with increasing concentration of Cu was observed, whereas Cu treatments did funt affect total chlorophyll and carotefunids content. An enhanced lipid peroxidation, in terms of malondialdehyde (MDA) content, was quantified in shoots when the plants were subjected to the highest Cu level, while in roots MDA levels showed a dose‐dependent increase along the increasing Cu concentrations applied. An increase of proline in roots of plants exposed to 200 μmol/L Cu was found. Antioxidant enzymes superoxide dismutase (SOD) and catalase (CAT) did funt show significant changes with respect to control, in both roots and shoots, despite mRNA‐specific accumulations varied between Cu levels and organs. Ascorbate peroxidase (APX) was negatively affected in shoots by the highest Cu level. Gene expression of the subtype 2d metallothioneins (MT) revealed to be Cu‐enhanced throughout the plant body and correlated with Cu tissue levels, with the other MT1 and MT2 gene members downregulated in roots and upregulated in shoots, contributing more as antioxidants in the latter organs than in Cu homeostasis. MT3s are not involved in Cu homeostasis and phytochelatin (PC) production was enhanced in roots of plants exposed to 200 μmol/L Cu, contributing to a higher Cu accumulation in these organs.

Root Morphologycal Responses of Oil Palm (Elaeis guineensis Jacq.) Hybrids to Copper Toxicity

“…Excessive Cu in root tissue could generate reactive oxygen species (ROS), including O2 -, H2O2, and the HO · radical, which caused lipid peroxidation and might caused membrane permeability damage (Andrade et al, 2010) led to ion leakage (De Vos et al, 1991), and also disrupt the activity of membrane-bound enzymes (Del Rio et al, 2006). Cell membrane was the primary site of Cu toxicity as proven by the increased lipid peroxidation (Fidalgo et al, 2013). Cu toxicity might also result from the strong interactions of Cu with sulfhydryl groups of enzymes and protein in the apoplast of root cell, which could inhibit enzyme activities or caused changes in the structure and replacement of key elements, resulting in deficiency of other nutrients (Yruela, 2005;Kabala et al, 2008).…”

Germination and initial development of Brachiaria brizantha and Brachiaria decumbens on exposure to cadmium, lead and copper

“…However, in the presence of Cu, B. decumbens presented inhibition in shoot growth, which reduced from 5.5 to 1.0 cm. The low translocation of trace elements from the root to the shoot causes the shoot to be little influenced by the seedlings exposure to the trace elements (Fidalgo et al, 2013).…”

“…However, in environmental conditions where copper is found in excess in the soil, plants may exhibit symptoms of toxicity which culminates in physiological disturbances inhibiting plant growth (Karimi, et al, 2012;Kabata-Pendias, 2011). Toxicity caused by Cu causes damage and disturbance in the integrity of the thylakoid membranes and photosynthesis impairment, which result in chlorosis or necrosis and inhibition of root and shoot growth (Yruela, 2009;Fidalgo et al, 2013).…”

Physiological responses of sweet potato (Ipomoea batatas L.) plants due to different copper concentrations

“…Excess Cu concentrations have been related to oxidative stress generation (SHI SHENG, 2007) and connected to the production of reactive oxygen species (ROS) in Fenton-like redox reactions (FIDALGO et al, 2013). ROS are generated as natural products of photosynthetic and aerobic metabolisms in plants.…”