Comparison of cadmium and copper effect on phenolic metabolism, mineral nutrients and stress-related parameters in Matricaria chamomilla plants

Abstract

Cadmium and copper uptake and its consequence for activity of selected enzymes of phenolic metabolism, phenolic acids accumulation, quantity of mineral nutrients and stress-related parameters in Matricaria chamomilla plants exposed to 60 μM and 120 μM for 7 days has been studied. Cu content in the above-ground biomass was ca. 10-fold lower compared to Cd and amount of Cd in the methanol-soluble fraction was lower than in the water-soluble fraction. "Intra-root" Cd represented 68% and 63% of total Cd content at 60 μM and 120 μM, but no difference was observed in Cu-exposed roots. Cu excess had more pronounced effect on shikimate dehydrogenase, cinnamyl alcohol dehydrogenase, polyphenol oxidase and ascorbate peroxidase activity mainly in the roots. Among eight detected benzoic acid derivatives and four cinnamic acid derivatives, the latter were preferentially accumulated in response to Cd excess. Content of salicylic acid increased in all variants. Amount of superoxide was elevated in both the rosettes (preferentially by Cu) and roots (preferentially by Cd). Accumulation of Ca and Mg was not affected by excess of metals, while potassium decreased in both the rosettes and roots (Cu caused stronger depletion). Amount of Fe increased in the roots in response to both metals (more expressively in Cu-treated ones). Present study using other metabolic parameters (and supplementing our previous studies) has confirmed higher Cu toxicity for chamomile plants, to support its strong pro-oxidant properties. These observations as complex metabolic responses are discussed.

Aspects of mycorrhizal colonization in adaptation of sweet marjoram (Origanum majorana L.) grown on industrially polluted soil

“…Higher correlation coefficients for FRAP were obtained in comparison with the DPPH test system. Oxidative stress due to heavy metal toxicity resulted in an increase in the activities of antioxidant metabolites such as phenolic compounds that participate in quenching reactive oxygen species (Kovačik et al, 2009). Our results indicate that the O. majorana antioxidant potential, defined by the concentration of phenolic compounds and flavonoids, considerably increases as a result of EEZ 35 and EEZ 54 application.…”

Influence of environmental factors on the concentration of phenolic compounds in leaves of Lafoensia pacari

“…Studies by Kováčik & Klejdus (2008) and Kováčik et al (2009) demonstrated high levels of phenolic acids in tissues rich in copper, suggesting that this mineral is an important enzyme activator for the synthesis of these compounds (by PAL). Another interpretation of the increased levels of phenolic compounds in these tissues, suggested by the same authors, is that this is associated with a mechanism of tolerance to Cu, since Cu is a catalyst for redox reactions that can produce free radicals harmful to the plant; consequently, increased levels of phenolic compounds have two goals: to decrease the concentration of free Cu in plant tissue by the reaction of this with phenols, and to minimize the deleterious effects of free radicals formed, through the antioxidant action of the phenolic compounds.…”

Characterization of Plant Antioxidative System in Response to Abiotic Stresses: A Focus on Heavy Metal Toxicity

“…The metabolism of several phenols has been reported to change under Cu and Cd stress indicating a putative role of these compounds in heavy metal detoxification by decreasing the presence of the free metal ions (Kováčik et al, 2009). Lignin accumulation has also been described as a consequence of Cu toxicity (Lequeux et al, 2010) but whether this is related to a heavy metal defence mechanism is still not clear.…”