Does Seaweed Extract as a Biostimulant Ameliorate Tomato Plant’s Salt Stress Tolerance ?

Seaweed extracts are considered a promising strategy in reducing plant stress. A growth experiment was designed to study the effect of an alkali seaweed extract (SE) on the morphology, physiology, and biochemical parameters of tomato plant grown under salt stress. The experiment consisted of five salinity levels (0.6, 4, 8, 12, and 16 dSm-1), and four levels of SE (0.0, 1, 3, and 6%). Salt stress decreased significantly shoot and root fresh weight, shoot and root water content, chlorophyll, fruit length, and fruit yield. Seaweed extracts significantly ameliorated tomato’s growth. Sprayed SE has increased significantly morphological parameters evaluated. Indeed, salinity increased the antioxidant enzymes (superoxide dismutase) and resulted in the accumulation of proline and lycopene. The results of this study demonstrated that spraying SE ameliorate the negative effect of salt stress in tomato plants.