Preliminary Study of Sodium Chloride Tolerance of Rudbeckia fulgida var. speciosa ‘Goldsturm’, Heuchera americana ‘Dale's Variety’ and Aquilegia × cultorum ‘Crimson Star’ Grown in Greenhouse Conditions
Abstract Heuchera americana ‘Dale's Variety’, Aquilegia × cultorum ‘Crimson Star’ and Rudbeckia fulgida var. speciosa ‘Goldsturm’ were grown in a soilless medium and watered weekly with either 0.00 (control), 0.05, 0.15 or 0.25 M NaCl solutions for 6 weeks. Foliage and leachate were analyzed for pH, Na+ and Cl−, and digital images were taken of all plants. Sodium and chloride concentrations in the leachate increased over time, while pH values remained unchanged. Aquilegia and Rudbeckia took up both Na+ and Cl−in increasing amounts over time. Heuchera took up large quantities of Cl−initially, but lesser amounts over time, and minimal Na+ into the foliage until the last week. At the highest treatment levels of NaCl, all plants showed significant visual damage. Aquilegia was the first to show visual damage at 0.05 M NaCl. Heuchera was intermediate in terms of symptom development. Based on the results of this study, Rudbeckia and Heuchera are listed as salt tolerant, and Aquilegia is listed as salt intolerant.