The biostimulating effects exerted by microalgae and cyanobacteria, such as Spirulina, are the result of the activity of a series of bioactive molecules released by themselves.
For example, algal extracts have the ability to increase the content of phytohormones in plant tissues: phytohormones are organic compounds produced in very low concentrations that function as chemical messengers in the regulation of various physiological processes in plants, and that act in all phases of plant development, from seed germination to senescence.
Among the most active and abundant components in microalgae and cyanobacteria are polysaccharides, which confer greater resistance to abiotic stress and pathogens, through the activation of signal molecules such as salicylic acid and jasmonic acid. Extracellular polysaccharides, on the other hand, improve the water capacity and bioavailability of macro and microelements in soils.
