Resumen
The present studyevaluated the biostimulating effect on seed germination and initial vegetativedevelopment of Phaseolus vulgaris L.bean seedlings in response to the application of the aqueous extract of Osmundaria obtusiloba (C. Agardh) RENorris (Rhodophyta) and Sargassum vulgareC. Agardh Ochrophyta), relating the activity with the contents of proteins andcarbohydrates of extracts. Seaweed dried biomass of macroalgae were extractedat the concentration of 500 g L-1 in distilled water, thisconcentration was considered 100%. After was prepared in dilutions of 25%, 50%, and 0% (negative control) for eachspecies. The experiment was conducted with 140 bean seeds in transparentplastic boxes kept in incubators under a12 hour photoperiod at the temperature of 25°C for 15 days.During this time, the germination percentage, germination speed and vigor ofthe seedlings (shoot length x radicle length) were assessed, as well as thesugar and total protein content of each seaweed extract. The results indicatedthat the development of seedling aerial biomass was 1.8 times higher with theextract at 25% concentration of O. obtusiloba thanwith the negative control. There were no changes in the germination parameters.Therefore, the O. obtusiloba extractshowed a more positive effect on initial development than that of S. vulgare. TheO. obtusiloba extract contained160 mg L-1 while that of S.vulgarecontained 80 mg L-1 total soluble proteins, indicating that proteincontent might be indicative of seaweed potential for application inagriculture.