Effect of safflower aqueous extracts (Carthamus tinctorius) on germination, seedling growth and enzymes activity of wild oat (Avena fatua) and barnyard grass (Echinochloa crus-galli)

In order to evaluate the effect of safflower aqueous extracts on seedling growth and enzymes activity of wild oat and barnyard grass, this experiment was arranged in a completely randomized design (CRD) with five replications in 2 separated experiments. Effect of different concentrations of safflower extracts (0, 10, 20, 30 and 40%) were examined on seed germination characters of wild oat and barnyard grass weeds. The results showed that in the concentrations of 30 and 40% of safflower aquatic extract, wild oat germination was 33.3% and 46.6%, respectively, and significantly decreased in comparison with control (93.3%). While, under 30 and 40% concentrations, barnyard grass germination was 30% lower than control treatment. Safflower extract reduced the activity of α-amylase enzymes in barnyard grass seeds. The activity level of α-amylase enzymes and wild oat seedlings in the treatment of 40% safflower extract was 2.2 and 1.9 nmol / g protein / min, respectively. Increasing the concentration of safflower extract resulted in degradation of cell membranes, increased free fatty acid levels, and decreased activity of barnyard grass catalase enzymes. In general, the allelopathic compounds in the aqueous extract of safflower reduced the amount and speed of germination of wild grasshoppers and wild oat by reducing the activity of α-amylase enzyme and increasing the peroxidation of membrane fats. Germination and seedling growth of wild oat compared to barnyard grass were more susceptible to safflower extract.