The 24-epibrassinolide induces rice tolerance to water stress overcoming losses in grain yield

Abstract

Water stress leads to large productivity losses in rice cultivation, and plant hormones play a key role in the plant strategies to prevent the harmful effects of water stress in crop development. The objective of this work was to investigate the effects of brassinosteroids (BRs) in rice development and yield under irrigation and under water deficit conditions applied during the preanthesis period. Exogenous applications of bioregulators were performed through leaf spray. Two dosages of 24-epibrassinolide (EBL) were applied (0.01 μM and 0.1 μM), in addition to two dosages of ABA (2.27 mM and 4.54 mM) in order to compare the effects, considering its already known beneficial effects in response to drought adaptation. Plants of the cultivar IRGA 424RI grown under greenhouse conditions were submitted to water deficit from V13 stage until reaching a leaf water potential of-2 MPa. Physiological, growth and biochemical parameters were measured. Even though the water stress reduced plant growth, 0.01µ M EBL-treated plants presented unchanged initial dry weight, height and tillering after the stress imposition. The 0.1 µM EBL-treated plants maintained the total dry weight of grains even after water stress imposition, while control and ABA-treated plants showed a 63.9% and 28.1-58.6% reduction, respectively. The 0.01 µM EBL treatment doubled the contents of chlorophyll a, b and total and decreased stomatal conductance under stress in 41.1%. EBL treatments were able to maintain similar peroxidation levels between stressed and non-stressed plants. When analyzed together, these results indicate that EBL shows a promising perspective for improving rice tolerance to controlled water stress.

Exogenously Used 24-Epibrassinolide Promotes Drought Tolerance in Maize Hybrids by Improving Plant and Water Productivity in an Arid Environment

“…In IWD stress conditions, a dose-dependent action has also been reported for other hormones, such as cytokinins and auxins [ 62 ]. Therefore, it is possible that the dose-dependent action of EBR 24 on stomatal behavior is due to its crosstalk with other plant hormones [ 32 ].…”

“…However, developing drought-tolerant hybrids require considerable effort, a long time, and high economical investments [ 26 , 27 ]. Therefore, some approaches can be helpful in this regard [ 6 , 26 , 28 , 29 ], including the use of plant hormones to enhance plant performance and output under IWD conditions [ 30 , 31 , 32 , 33 , 34 ].…”