Brassinosteroids induces tolerance to water deficit in soybean seedlings submitted to water deficit:
Contributions linked to root anatomy and antioxidant enzymes
Antioxidant metabolism ● Drought ● Glycine max ● Metaxylem ● 24-epibrassinolide
Our hypothesis considered that the soybean crop is a species susceptible to drought, especially during the germination period. Additionally, recent research has revealed that brassinosteroids (BR) promoted benefits on root anatomy. Therefore, this study aimed to evaluate if BR can mitigate the negative effects promoted by the water deficit, evaluating the anatomical, physiological and morphological responses in soybean seedlings. In this experiment, soybean seeds were submitted to two water regimes (control and water deficit) induced by PEG 6000 and three levels of EBR (0, 50, 100 nM BR). This research revealed that BR promoted improvements in most variables analyzed. BR promoted increases in root tissue avoiding water reflux in all anatomical variables such as epidermis, endoderm, cortex, vascular cylinder and metaxilema. In parallel, this steroid promoted greater energy release for the process of degradation of seed reserves, increasing the percentage of total germination. Additionally, BR increased the activities of antioxidant enzymes, such as catalase, peroxidase, superoxide dismutase and ascorbate peroxidase. BR mitigated damage to cell membranes by reducing ROS levels such as superoxide, hydrogen peroxide, MDA and electrolyte leakage. Thus, seedling growth results are intrinsically linked to the effect of BR on reducing ROS levels and promoted the growth of radicle, hypocotyl length and total length in soybean seedlings.