24-epibrassinolide relieves damages caused by inadequate supplementation of boron and zinc in plants.

Abstract

Boron (B) and zinc (Zn) are essential micronutrient for plant growth. B regulates the structural and membrane integrity of the cell wall and plasma membrane, ion mobility across the membrane, cell division and elongation, reproductive growth, biomolecule synthesis. Zn it plays important roles in plant development, reproduction and signaling due to its structural, catalytic and activating functions. Brassinosteroids (BRs) are a class of steroid hormones that regulate a number of physiological processes. EBR is the most active form of BRs, and exogenous application of EBR can ameliorate the effects of abiotic stresses. Therefore, the objective of this research was to investigate whether application of EBR can alleviate the effects of inadequate boron and zinc supplementation in soybean and tomato seedlings. Two experiments were carried out, the experiment 1 was with soybean plants under three levels of boron supplementation (control, low, and high B) and two EBR conditions (0 and 100 nM), and the experiment 2 was with tomato plants under three levels of zinc (control, low, and high Zn) ) and two EBR conditions (0 and 100 nM). Both experiments was performed at the Campus of Paragominas of the Universidade Federal Rural da Amazônia, Paragominas, Brazil (2°55’ S, 47°34’ W). The study was conducted in a greenhouse with the temperature and humidity controlled. This research has shown that the application of EBR relieved the stress caused by B in soybean plant and Zn in tomato plants, synergistically stimulating leaf and root structures, photosynthesis, and growth. Therefore, our results show that EBR application could help improve plants’ tolerance to boron and zinc stress.