Influence of Seaweed Extracts (Sargassum dentifolium or Padina gymnospora) on the Growth and Physiological Activities of Faba Bean and Wheat Plants Under Salt Stress

THE CHANGES of growth and some physiological parameters in faba bean (Vicia. faba L. cv. Masr-1) and wheat (Triticum vulgare L. cv. Sakha-94) treated with NaCl levels and seeds soaking for 12 hr in 1% seaweed water extracts from Sargassum dentifolium or Padina gymnospora collected from the red sea, Hurghada, Egypt were studied. Fresh, dry mass and photosynthetic pigments contents (Chl.a, Chl. b and Car.) of both plants significantly decreased in response to salt stress. The highest salinity levels (150 and 200 mM NaCl) resulted in injurious effects led to death of the tested plants (faba bean and wheat, respectively). Salinity induces a significant decline in the activity of ascorbate peroxidase (APX) of faba bean and peroxidase (POD) of wheat. On the other hand, there was marked increase in the activity of superoxide dismutase (SOD), catalase (CAT), of the two plants, POD of faba bean and APX of wheat compared to untreated plants. Application of 1% aqueous extract of S. dentifolium or P. gymnospora by seed soaking was accompanied by stimulation in growth, photosynthetic pigments and the activity of antioxidant enzymes. The higher activity was observed for extract of S. dentifolium. In contrast, treatment with seaweed water extracts resulted in significantly decreased in MDA content, which increased under salinity stress. All the previous findings suggested the possibility that seaweed water extracts may play an important role in increasing plant resistance by stimulating the antioxidant enzyme system which associated with a marked retardation in the MDA content.