Evaluation of the Condition of Wheat Seedlings Growing Under Drought Stress Treated with the Copper-Quercetin Complex

One way to counteract the effects of environmental stresses, including drought, is to use products with growth-promoting properties for plants. Such agents include quercetin, which is known for its antioxidant and photosynthesis-enhancing properties. In the conducted experiment, the influence of the quercetin-copper complex (Q-Cu (II)) treatment, characterized by strong high solubility in water and strong antioxidant properties, was investigated. The pot experiment demonstrated the effect of spraying with Q-Cu (II) solutions (0.01, 0.05 and 0.1%) on wheat plants growing under drought stress conditions. Two treatments of Q-Cu (II) solutions were applied, and chlorophyll content and chlorophyll fluorescence (the maximum quantum yield of photosystem II (PSII) photochemistry (Fv/Fm), the maximum quantum yield of primary photochemistry (Fv/F0), and the photosynthetic efficiency index (PI)), as well as gas exchange (photosynthetic network intensity (PN), transpiration rate (E), stomatal conductance (gs) and in-tercellular CO2 concentration (Ci)), were measured 1 and 7 days after each treatment. In addition, antioxidant enzyme activity (catalase (CAT), peroxidase (SOD) and guaiacol peroxidase (GPOX)) and reactive oxygen species (ROS) levels were determined. Drought stress caused a decrease in chlorophyll content, and values of parameters Fv/Fm, Fv/F0, PI and PN, E, gs, Ci, as well as an increase in ROS levels and antioxidant enzyme activity. The study showed that exogenous ap-plication of Q-Cu(II), especially at a concentration of 0.1%, had a stimulating effect on plants, causing an increase in the tested physiological parameters and enzymatic activity. The conducted research indicates the possibility of using Q-Cu(II) as a product to enhance the efficiency of the photosynthetic process under drought stress.