Influence of sodium chloride on selected growth parameters and macronutrient content in pelargonium leaves

The aim of this study was to assess the potential of cultivation of Pelargonium × hortorum cv. Survivor Dark Red in a substrate contaminated with sodium chloride. After applying 0.45, 0.96, 1.47, 1.98, 2.49, 2,99 g NaCl dm-3, the substrate contained 200, 400, 600, 800, 1000, 1200 mg Na+ and 287, 595, 903, 1211, 1519, 1827 mg Cl- dm3. Growing medium with natural sodium (22 mg Na+) and chloride (13 mg Cl-) content comprised the control. Electrical conductivity (EC) of the substrates was as follows: 0.11, 0.62, 1.28, 1.75, 2.42, 2.82, 3.72 mS cm-1. Water purified by reverse osmosis was used for watering the pelargonium plants. The effect of sodium chloride on the chemical composition of leaves was evaluated based on the analysis of leaf blades collected at the flowering stage. Sodium chloride negatively influenced all measured plant growth parameters. Increasing salinity also decreased the chlorophyll index values. Significant reduction in the number of inflorescences was recorded in plants grown at ≥ 800 mg Na+ and ≥ 1211 mg Cl- in 1 dm3 of peat substrate. However, the pelargonium plants grown in a substrate containing up to 600 mg Na and 903 mg Cl still retain high decorative value. The increasing sodium chloride content in peat substrate increased the concentrations of phosphorus and calcium in the leaves. Simultaneously, the concentrations of potassium and magnesium decreased, while the concentration of nitrogen was found to be stable. Despite increasing doses of sodium chloride, the content of N, P, K, Ca and Mg in pelargonium leaves fell within or slightly exceeded the established range of guideline values.