LAUSR

Biological effects of extracts obtained from the seaweeds Hormophysa cuneiformis (J.F.Gmelin) P.C.Silva and Actinotrichia fragilis (Forsskal) Burgesen were investigated using wheat for the improvement of growth and amelioration of the negative effects of soil salinity. Exposure of plants to salt stress resulted in an overall decrease in growth, chlorophyll a and b, carotenoids and soluble sugars, as well as nutrient uptake (i.e., K, Ca and Mg) and K+/Na+ ratio. At the same time, increases were found in proline, total free amino acids, phenolic compounds, malondialdehyde (MDA), Na+ ions, as well as the activities of peroxidase (POD), catalase (CAT), and superoxide dismutase (SOD). Priming wheat seeds with H. cuneiformis and A. fragilis extracts mitigated the negative impacts of salinity by enhancing growth and all the above attributes except MDA and Na+. Treatments with H. cuneiformis or A. fragilis extracts resulted in an increased intensity of the polypeptide bands with 200, 159, 120, 40, and 22 KDa which were already apparent in the control. A. fragilis showed higher effectiveness than H. cuneiformis extracts under both control and stressed regimes. Our results highlight “biofertilizer” properties of two seaweeds and furnish mechanistic insight into their salinity-improvement action, which is pertinent for both applied and basic research.