Abstract: To investigate the induction effect of exogenous 2,4-epibrassinolide (EBR) on saltresistance of oat seedlings and reveal the potential physiological mechanism, we examined the effects of EBR on the absorption, transportation, and allocation of inorganic ion in oat seedlings under NaCl stress, with Avena sativacv. ‘Qingyin No. 2’ and cv. ‘Jiayan No. 2’ as materials. Results showed that under 100 mmol·L^-1 NaCl stress, the content of Na⁺ and Cl^- in leaf and root of ‘Qingyin No. 2’ and ‘Jiayan No. 2’ seedlings increased significantly. NaCl stress had antagonistic effects on cationic absorption, with reductions of contents of K⁺, Ca²⁺, Mg²⁺, Fe²⁺, Mn²⁺, Cu²⁺, and Zn²⁺ as well as a disordered ion equilibrium in leaf and root of oat seedlings. Under 100 mmol·L^-1 NaCl stress, the addition of 0.01 μmol·L^-1 EBR significantly reduced the content of Na⁺ and Cl^- in leaf and root of ‘Qingyin No. 2’ and ‘Jiayan No. 2’ seedlings, while the absorption of K⁺, Ca²⁺, Mg²⁺, Fe²⁺, Mn²⁺, Cu²⁺, and Zn²⁺ was improved, and the ratios of K⁺/Na⁺, Cl^-/Na⁺, Ca²⁺/Na⁺, Mg²⁺/Na⁺, Fe²⁺/Na⁺, Mn²⁺/Na⁺, Cu²⁺/Na⁺, and Zn²⁺/Na⁺ were increased significantly; the transport ratio of inorganic ions and the transport selectivity ratio of cations were effectively regulated, and the steady state of ion recovered. Our results suggest that exogenous EBR could alleviate the toxicity of Na⁺ and Cl^- to oat seedlings under NaCl stress and effectively regulating the selective absorption, transportation, and allocation of inorganic ions in oat seedlings, with a positive regulatory effect on ion steady-state equilibrium in oat seedlings.

Key words: grain position, rice quality, ozone stress, amylose