Net Photosynthesis and Biomass Production in Stevia, Eggplant, and Cowpea Can Be Improved by Fertilization with Cyanobacteria (<i>Limnospira maxima</i>)

Abstract

Conventional fertilizers often result in the accumulation of chemical residues in the environment with a significant threat to ecosystems, with leaching to the groundwater disrupting the delicate balance of ecosystems. To mitigate the adverse effects of chemical residues, we need new methods and the use of eco-friendly alternatives. Cyanobacteria could play a crucial role in sustainable agriculture by reducing the partial/complete use of synthetic fertilizers. This study assessed the impacts of different concentrations of Limnospira maxima extract on the physiological aspects of Vigna unguiculata, Stevia rebaudiana, and Solanum melongena. The gas exchange parameters, chlorophyll a fluorescence, and phenotypic characteristics were measured. The net photosynthesis (AN) of V. unguiculata, S. rebaudiana, and S. melongena increased by 23%, 40%, and 44%, respectively, upon the application of cyanobacteria extracts. Furthermore, the quantum yield of photosystem II showed that the extract application enhanced this response in the three species by 8.7%, 4.8%, and 11.3%, respectively. Similar results were found in the total plant biomass production with significant increases of 17%, 130%, and 80% with respect to the control. Moreover, a positive correlation was observed between AN and the majority of the evaluated parameters, which could illuminate the plant’s responses to the studied treatments. The promising potential of this cyanobacteria as a biofertilizer was accentuated.

Keywords

• cyanobacteria
• plant physiology
• net photosynthesis
• photosystem II
• biomass