Microalgae-Based Biostimulants: Effects on Growth and Stress Resistance in Agricultural Crops

Microalgae grow rapidly, require minimal space, can proliferate in non-agricultural land, do not compete with human food sources, and can be cultivated in a variety of environments, including wastewater. They are considered an ecological source of bioactive compounds, offering an environmentally friendly alternative to conventional industrial production methods, which are often resource-intensive. It is important to emphasize that both the species of microalgae and the specific culture conditions play a decisive role in the generation and storage of valuable bioactive compounds, which can act as biostimulants. Biostimulants are organic compounds or microorganisms capable of enhancing crop quality parameters by optimizing nutrient and water use efficiency, while also strengthening tolerance to abiotic stress. The aim of this article is to provide an updated understanding of biostimulants, their modes of action, and their role in regulating plant responses to abiotic stress. It further incorporates examples of successful trials that demonstrate the advantageous applications of microalgae-based biostimulants, while also addressing the barriers and limitations to their commercialization and integration into sustainable agricultural practices.