A brassinosteroid analogue prevented the effect of salt stress on ethylene synthesis and polyamines in lettuce plants

Abstract The present study was carried out to analyze the effect of treatment with DI-31, a brassinosteroid analogue (0.1 or 1 μM), on alleviating salt stress in lettuce plants. After application of DI-31, 100 mM NaCl treatments were administered. Samples that were separated into shoots and roots were taken 5 days after this application. DI-31 alleviated the reduction of weight due to NaCl with a greater effect at 1 than at 0.1 μM. The emission of ethylene increased with the application of NaCl, and the DI-31 treatment decreased this effect in shoots and roots. Similar results were obtained in ACC, since its concentration was increased by salinity, and DI-31 was effective in reducing it. The putrescine content decreased with salinity and DI-31 reversed the effect in the shoots, while it remained constant in the roots. The spermidine and spermine contents in roots increased with salinity. The DI-31 reversed the effect of NaCl in both shoots and roots in the two polyamines, except in shoots where the spermine content was maintained. Since the DI-31 brassinosteroid has partially reversed the negative effect of NaCl on lettuce plants, we conclude that the brassinosteroid has a protective effect against salinity.