Physiological Allelopathic Effect of Aqueous Extracts of Cucumber, Carrot, Onion, and Garlic Seeds on Germination and Growth of Pea

Allelopathic potential of aqueous extracts of cucumber, carrot, onion and garlic seed on germination and growth of pea was studied. Aqueous extracts at 0.0, 10, 30 and 60% concentrations were used. The results indicate that both cucumber and carrot seeds extracts exerted positive allelopathic effects and improved seed germination, growth and metabolic activities of pea seedlings. Also, the data showed that both cucumber and carrot seeds extracts led to increased auxin content and decreased abscisic acid content of pea seedlings. On the other hand, onion and garlic seed extracts had significant negative allelopathic effects on seed germination, growth parameters and metabolic activities of pea seedlings. Extracts of onion and garlic seeds led to pea seedlings of higher abscisic acid content and lower auxin content. All extracts exerted concentration dependent allelopathic effects on pea growth.