Spermidine Pretreatments Mitigate The Effects Of Saline Stress By Improving Growth And Saline Excretion In Frankenia Pulverulenta

Climatic change, ecosystem imbalance, and soil salinization and desertification are serious obstacles to the restoration of degraded landscapes. Halophyte cultivation could constitute a way of mitigating these problems. Frankenia pulverulenta is used in the remediation and revegetation of areas affected by salinity and as an ornamental plant on saline soils since it can tolerate salt concentrations up to 200 mM NaCl. To increase saline tolerance, different plant growth regulators (auxins, cytokinins, gibberellins, spermidine, and salicylic acid) were tested in hydroponic conditions before the addition of NaCl (300 mM). At 52 days, growth, proline, saline excretion, free polyamines, and ethylene were determined under both saline and non-saline conditions. All growth regulators improved growth in the salt-free pretreatment; however, under conditions of salinity, pretreatment with spermidine (0.5 mM) and then salicylic acid (0.5 mM) were efficient at reversing the inhibitory effect of salt and improved saline excretion in F. pulverulenta. A strong positive correlation of polyamines and proline, and a negative correlation with ethylene, indicate that pretreatments that increase endogenous polyamine content and osmolytes are the most effective in improving salt tolerance of F. pulverulenta and could be used in the technical guidance of the cultivation of this halophyte.