Foliar Application of Ulva rigida Water Extracts Improves Salinity Tolerance in Wheat (Triticum durum L.)

This study investigated the effect of seaweed extract (SWE) sprays obtained from Ulva rigida on wheat plants (Triticum durum L., variety Karim) grown under salt stress conditions for six weeks. Three levels of NaCl (0, 34.22, 68.44 mM) and four different concentrations (0, 12.5, 25 and 50%) of Ulva rigida as a water extract were applied. The obtained results indicated that seaweed treated plants showed higher ability to tolerate salt stress (34.22 or 68.44 mM of NaCl) by a significant (p < 0.05) increase of plant growth and the photosynthetic pigment contents, compared to those of control (non-treated plants). Furthermore, there was a significant improvement in antioxidant enzyme activity, such as superoxide dismutase (SOD), isocitrate dehydrogenase (ICDH), glutathione peroxidase (GPx), glutathione reductase (GR) activities in the stressed plants, especially in those treated with 12.5% of SWE. Overall, our results suggest that the application of the Ulva rigida water extract could be used as a promising plant growth biostimulant for treating wheat plants under salinity stress.