Silicon modulates the activity of antioxidant enzymes and nitrogen compounds in sunflower plants under salt stress

• Published in: Archiv für Acker- und Pflanzenbau und Bodenkunde Vol. 65; no. 9; pp. 1237 - 1247
• Main Authors: Conceição, Susana Silva, Oliveira Neto, Cândido Ferreira de, Marques, Elton Camelo, Barbosa, Antonio Vinícius Correa, Galvão, Jessivaldo Rodrigues, Oliveira, Tamires Borges de, Okumura, Ricardo Shigueru, Martins, Jéssica Taynara da Silva, Costa, Thays Correa, Gomes-Filho, Enéas
• Format: Journal Article
• Language: English
• Published: Abingdon Taylor & Francis 29.07.2019; Taylor & Francis Ltd
• Subjects: Abiotic stress; Antioxidants; Ascorbic acid; Catalase; Electrolyte leakage; Enzymatic activity; Enzyme activity; Enzymes; Helianthus annuus; L-Ascorbate peroxidase; Metabolism; Nitrate reductase; Nitrates; Nitrogen; Nitrogen compounds; Nitrogen metabolism; Nutrient content; oxidative stress; Peroxidase; Proline; Salinity; Salinity effects; Salts; Silicon; SiO; Sodium chloride; sodium metasilicate (Na; Sunflowers; Superoxide dismutase
• ISSN: 0365-0340; 1476-3567
• DOI: 10.1080/03650340.2018.1562272

Sunflower (Helianthus annuus L.) is an important oilseed crop with clear sensibility to salt stress. In this study, we evaluated silicon (Si) effect on the nitrogen metabolism and antioxidant enzyme activity in sunflower plants subjected to salinity. A 4 × 4 factorial arrangement of treatments in a completely randomized design with four replicates was used, consisting of four concentrations of Si (0.0; 1.0; 1.5; and 2.0 mM) and four concentrations of NaCl (0; 50; 100; and 150 mM) in the nutrient solution. The salinity reduced the nitrate content, but the increasing Si concentration in the medium improved the nitrate uptake, leading this ion to accumulate in salt-stressed plants, particularly in the roots. The nitrate reductase activity and the proline and soluble N-amino contents were also significantly increased by Si in salt conditions. The salinity increased electrolyte leakage and reduced the activity of enzymes superoxide dismutase, ascorbate peroxidase and catalase in sunflower plants, but these decreases were reversed by Si at 2 mM, thus alleviating the effects of salinity on these variables. We conclude that Si is able to positively modulate nitrogen metabolism and antioxidant enzyme activities in sunflower plants in order to alleviate the harmful effects of salinity.