Speaker
Description
Soil ecosystems enclose an important diversity of microorganisms assuring different ecological key roles. Cyanobacteria and eukaryotic microalgae can enhance soil organic matter, and support its stability, water retention, fertility, and nutrient availability. Microalgae can be exploited in many sectors, especially in agriculture, as a new emerging category of plant biostimulants and an environmentally friendly tool for sustainable agriculture. This study aimed to investigate the diversity of soil microalgae and cyanobacteria in the Marrakesh-Safi area and to screen their aqueous extracts' biostimulant effects on wheat seed germination. The soil cultivation approach showed twenty-nine taxa in collected soils including sixteen cyanobacteria, eleven chlorophyta, and two diatoms. Redundancy analysis of soil physicochemical parameters and specific richness of the three algal groups revealed a positive correlation between the richness of cyanobacteria and nitrogen, ammonium, and humidity, whereas diatoms richness was more related to a high concentration of silica, whilst chlorophyta richness was associated with chlorine and pH. Six strains were chosen for the biostimulant bioassay based on their growth rate and biomass productivity, of which three cyanobacteria Nostoc sp.1, Nostoc sp.2, and Phormidium sp. and three chlorophyta: Stichococcus bacillaris, Coellastrella sp., and Chlorococcum sp. The results showed that all strains displayed a positive effect on wheat seeds by increasing the germination index, coleoptile length, and root length compared to the control (two-way Manova, p<0.05). Nevertheless, significant differences in terms of strain extract performance were observed. Aqueous extracts of Nostoc sp.1, Stichococcus bacillaris, and Coellastrella sp. were the most performant, as they increased germination index by 25.14%, 20%, and 19% respectively. Whereas the increases in coleoptile and radicle length were between 54.65% and 38.83% in comparison with the control. Our findings highlighted the potential of soil microalgae isolates for the production of liquid extracts with biostimulant activity and potential uses in agriculture.
