Microalgae can stimulate plant growth through bioactive compounds such as cytokinins, gibberellins, and abscisic acid. Here, we present novel insights into applying live microalgae cultures-Chlorella sp. and Scenedesmus obliquus-at different concentrations in lettuce cultivation, cv. 'Emocion'. Plants were grown in perlite under greenhouse conditions. Microalgae suspensions were prepared using fresh weight concentrations of 0.775, 0.0775, and 0.00775 g L-1, corresponding to cell densities of 2 × 107, 2 × 106, and 105 cells mL-1, respectively, and applied to the substrate as 140 mL per plant. The control received no microalgae application. Chlorella sp. significantly improved head weight and total yield, with the 0.775 g L-1 concentration being the most effective. Total yield increase was 18.3% compared to the control. For S. obliquus, the optimal effect was observed at 0.0775 g L-1, yielding a 2.7% higher yield than the control. Heatmap analysis revealed two primary treatment clusters, separating Chlorella sp. from S. obliquus and the control, with Chlorella sp. closely associated with yield-enhancing parameters. We concluded that Chlorella sp. application can effectively increase yield with 0.775 g L-1 identified as the most beneficial dose. Future research should investigate the mechanisms of microalgae-plant interactions and evaluate their applicability across various crops and cultivation systems.
Keywords: Chlorella sp.; Lactuca sativa; Scenedesmus obliquus; Heatmap; Soilless culture.
© 2025. The Author(s).