Biostimulant potential of three chlorophyta and their consortium: application on tomato seeds

Abstract

Microalgae offer a promising solution for enhancing agricultural sustainability and mitigating global warming. When extracts from algal cells and their spent medium are used as biostimulants on crop seeds, they can significantly influence plant physiology. This application boosts plant productivity and improves tolerance to abiotic stress. The objective of this study was to evaluate the biostimulant potential of crude extracts from Tetradesmus obliquus, Chlamydomonas reinhardtii, Auxenochlorella protothecoides, and their consortium, as well as the potential of their spent growth media, when applied to tomato seeds (Solanum lycopersicum). The study assessed germination indexes and seed development, including weight, root/shoot ratio, and growth speed. The results indicated that the variation in the morphology of the treated seeds was primarily influenced by the concentration of the extracts, with the algal species having a lesser impact on the observed variability. The number of germinated seeds was notably higher at the lowest concentration of biostimulants. Additionally, the algal extracts exhibited greater biostimulant potential than the spent media. Furthermore, the analysis of growth speed revealed that most treated seedlings grew significantly faster than the control seeds. Lastly, the study reported a lower biostimulant potential of the algal consortium compared to the single species, possibly due to the co-cultivation of different species.