Spermidine priming mitigated the Na+ toxicity damage in Leymus chinensis

Polyamines play important regulatory roles in mitigating salt damage to the plant in response to salt-alkali stress environment. To explore an effective pathway alleviating the osmotic damage to the plants, exogenous signal molecules had largely been applied. Spermidine, as one component of polyamine, was widely used to improve the plant tolerance to the abiotic stresses, but the regulatory mechanism of spermidine-mediated in alleviating ion toxicity still lacks detailed report. In this study, spermidine priming seeds was performed to unveil the physiological responsive effects of spermidine-triggered in Leymus chinensis under salt-alkali stress. Measurements show that spermidine priming seeds remarkably increased the antioxidant enzymatic activities and strengthened polyamines synthesis pathway, and simultaneously beneficially altered the accumulation of proline and soluble sugar, but reduced malondialdehyde accumulation, thus mitigating the oxidative damage in Leymus chinensis seedlings. Data also shows that spermidine priming seeds significantly inhibited the uptake of harmful Na+ but promoted the accumulation of K+ and Ca2+, thus lowering the osmotic damage to the plant cell membranes. This study provides novel insights into the regulatory pathway of exogenous spermidine-mediated in mitigating the oxidative and ion toxicity damages to Leymus chinensis.