Does brassinosteroid mitigate salt stress in sorghum?

Abstract

The objective of the present study was to assess the mitigating effect of brassinosteroid regulator plant on damages caused by salt stress in sorghum. The experiment was carried out in pots containing 5 kg of substrate, on benches in a greenhouse covered with transparent plastic film and with a 50% shade screen on the sides. A completely randomized design with four replications was used, in a 2×5 factorial arrangement consisted of application and non-application of brassinosteroids at concentration of 0.1 mg L-1 applied at the 30, 37, and 45 days after emergence (DAE) and five salinity levels of the irrigation water (electrical conductivities of 0, 2, 4, 8, and 16 dS m-1). The plants were irrigated with water from the public supplying system up to 45 DAE and, then, with brackish water up to 60 (DAE), when they were evaluated. Our results indicate that Brassinosteroids mitigated damages caused by salt stress by increasing the Ca to Na ratio. Sorghum is moderately resistant to salt stress by presenting a sodium extrusion mechanism activated by calcium. Further studies with longer exposure time to salt stress are recommended for a more thorough understanding and recommendation of the use of brackish water in sorghum crops