Silicon application alleviates the effects of salt stress in sorghum and sunflower plants

• Autor(a) principal: Hurtado, Alexander Calero [UNESP]
• Data de Publicação: 2020
• Tipo de documento: Tese
• Idioma: eng
• Título da fonte: Repositório Institucional da UNESP
• Texto Completo: http://hdl.handle.net/11449/191852
• topic: Helianthus annuus; Sorghum bicolor; Beneficial element; Enzymatic activity; Nutritional efficiency; Oxidative stress; Proline; Salinity

The effect of silicon (Si) on physiological and nutritional mechanisms to attenuate salt stress depends on the species and the mode of supply of the beneficial element. The objective of this study was evaluated whether supplied Si in different mods-manner attenuates the deleterious effects of salt stress based on the biochemical, physiological and nutritional responses of two distinct species, sorghum (accumulator of Si) and sunflower (intermediate accumulator of Si) under greenhouse conditions. Two pots experiments were carried out in a randomized block in a factorial scheme (2 × 4) with two factors, include salinity which was applied to the root medium as sodium chloride (NaCl), with the control and salt-stress groups (0 and 100 mmol L-1 NaCl), and the plants from each group were combined with the following Si-treatment groups: control (no Si), foliar application (28.6 mmol L-1), root application (2 mmol L-1), and combined foliar and root applications. Stabilized sodium and potassium silicate (SiNaKE) were used to maintain the Si levels. We tested the effects of different methods of Si applications in the response of mineral and water uptake, lipid peroxidation, proline concentration, enzymatic antioxidants activities, root diameter, leaf area, uptake and use efficiency of macronutrients and micronutrients in sorghum and sunflower plants under salinity stress conditions. Forty days after cultivation, in the stage S4 for sorghum and V8 for sunflower, the plants were harvested. Salinity stress decreased all the biological parameters. Si application resulted in higher K+ accumulation, and lower Na+ accumulation and lipid peroxidation levels in sorghum and sunflower leaves compared with untreated plants. In addition, Si increased the leaf relative water content, modified the proline content, enhanced enzymatic antioxidants activities, root diameter, leaf area, nutritional efficiency, and roots, shoots, and whole dry matter. These increases were more prominent under salinity stress, when Si was applied via nutrient solution in sorghum plants and the combined foliar and root applications of Si in sunflower plants. Our results also suggest that foliar Si spraying may be important in the biochemical and physiological activities for growth and development of both salt-stressed sorghum and sunflower plants.