Determination and quantification of two regulatory phytohormones extracted from Sargassum muticum and Gracilaria corticata seaweeds in the south of Iran

In the present study, two regulatory phytohormones, abscisic acid and auxin, were extracted from two different macroalgae, Sargassum muticum and Gracilaria corticata, for the first time. Sampling was performed each month with three replicates, from Bushehr Province shores located in the north region of Persian Gulf for six alternative months. The alteration of seaweeds biomass and the probable impacts of some environmental factors were measured. The extracted phytohormones were isolated employing HPLC method and identified by injection of standards. The highest amount of ABA phytohormone in the two species, occurred in November. Also, the highest amount of Auxin in Sargassum muticum was reported in May, while the highest amount of this hormone in Gracilaria corticata was observed in January. In January, the maximum mean biomass in Sargassum muticum was 679gr/m2, while the minimum mean of 20.66gr/m2 was observed in September. Moreover, the highest average biomass in Gracilaria corticata was 423/33gr/m2 in March and the lowest mean of 158g/m2 was reported in November. ANOVA and Chi-squared test results showed a significant difference in all samples. These phytohormones could be applied in preparing algae liquid fertilizer in future studies.