the effects of blue-green algae nostoc commune aqueous extract on the growth parameters, metabolite contents, and antioxidant capacity in seedlings of a local iraqi rice (amber) variety

Blue-green algae have significant potential for enhancing the productivity of various agricultural crops. in this study, the effects of nostoc commune extract on the physiological parameters of a local rice variety were evaluated. the extract was prepared at a concentration of 0.5 g per 100 ml of distilled water, and rice seeds were treated with extract dilutions of 0%, 20%, 40%, 60%, 80%, and 100%. different concentrations of n. commune extract produced varied physiological responses in rice. all extract concentrations significantly increased radicle length and seedling weight. germination percentage was significantly improved by 20% and 60% treatments, while the 40% concentration notably enhanced hypocotyl length. in terms of biochemical parameters, all concentrations significantly increased metabolite content. most concentrations also led to a significant rise in chlorophyll levels, and carotenoid content was the highest in 100% extract treatment. the 60% concentration resulted in the highest carbohydrate and protein levels. the greatest accumulation of phenols and flavonoids was observed with the 20% extract. additionally, antioxidant capacity was significantly enhanced by the 20% and 40% concentrations. overall, based on improvements observed in both growth and biochemical parameters, aqueous extract of n. commune at concentrations below 60% can be recommended as an effective biostimulant and biofertilizer for enhancing rice yield.