Arthrospira platensis (Spirulina) as a Sustainable Biofertilizer: Influence on Radish Growth and Seed Germination

HistoryThis study assessed the effect of Arthrospira (Spirulina) platensis as a biofertilizer on the germination and development of Raphanus sativus (radish).A semi-open photobioreactor with Zarrouk medium was employed for the cultivation of the cyanobacterium.The temperature was maintained at 32°C using a heater, and aeration was controlled through a 6/30 pumping cycle to ensure proper gas exchange.A 12-hour light/12-hour dark photoperiod was used with artificial fluorescent light.After harvesting, different biofertilizer formulations were prepared from dry biomass and cultures in the exponential phase, which were compared with a commercial fertilizer and a control treatment.Variables such as germination rate, number of leaves, stem height, leaf width, and survival rate were analyzed.The results showed that treatments with spirulina improved the germination rate, with treatments T2 and T4 showing the best results.Moreover, during the growth stage, these treatments significantly increased stem height, leaf number, and survival rate compared with the commercial fertilizer.Statistical analysis using ANOVA, Tukey's test, and principal component analysis (PCA) confirmed significant differences between the treatments, supporting the effectiveness of the microalga-based biofertilizer as an alternative to conventional fertilizers, demonstrating its potential as a natural biostimulant.