Toxicity of Copper for Plants in Hydroponic Cultivation: Morphological, Physiological and Epigenetic Analysis

Due to the increasing agricultural and industrial activities, which are the main sources of soil contamination with copper (Cu), there is a need to monitor the environment as well as analyze plants capable of growing in an environment with high Cu concentrations. The present study investigated the growth of two plant species: barley (Hordeum vulgare L.) and lupine (Lupinus albus L.) grown under different concentrations of toxic levels of Cu2+ (50/100/200 µM) in hydroponic conditions. The analysis focused on plants’ reactions at the morphological, physiological, and epigenetic levels. Copper induced mainly inhibitory effects on the analyzed parameters of both barley and lupine plants. However, effects depended on the parameters analyzed as well as plant species. A negative reaction was observed mainly after high doses of copper treatment. Barley and lupine plants also react to different copper concentrations by changing DNA methylation profiles. Plants treated with the Cu ions indicated a lower % of total DNA methylation in comparison to control plants. Studying these response mechanisms in plants will contribute to improving the understanding of the basic mechanisms of high-level copper response and constitute an important tool for the selection of more tolerant genotypes.