Recovery of tobacco plants after copper ions application

The aftereffects of copper ions (100 and 300 pM) on the organ size, the content of stress markers (hydrogen peroxide, lipid peroxidation - LPO) and components of the antioxidant status (superoxide dismutase -SOD and guaiacol peroxidase - GPO) were studied in the roots, stem, and leaves of Nicotiana tabacum L. It was shown that tobacco plants were sensitive to long-term exposure to 100 and 300 pM Cu2+. Both concentrations inhibited root growth, while shoot length and thickness, and leaf area decreased only in the case of pretreatment with 300 pM Cu2+. So, the growth of aboveground organs was suppressed significantly less than the root. The level of lipid peroxidation and the content of hydrogen peroxide in the roots under these conditions were also higher, which indicates a stronger stress, compared to stem and leaf. The activity of antioxidant enzymes SOD and GPO in roots and aboveground organs specifically changed depending on the concentration of copper ions and the type of organ. In the roots, there was a decrease in SOD activity and an increase in the activity of GPO under pretreatment with 300 pM Cu2+, compared to the control and 100 pM Cu2+, while in stem and leaves the activity of enzymes decreased. The data obtained indicate incomplete plant recovery under the aftereffect of copper ions.