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

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.

Micropropagation Protocols for Three Elite Genotypes of Stevia rebaudiana Bertoni

“…The selection of the elite genotypes (here referred to as L020, L102, and Morita II; [37]) for the mass multiplication program through tissue culture cultivation is grounded in strategically utilizing genetic variability to optimize crop yields. In a comparative analysis, genotypes L020, Morita II, and L102 stand out by demonstrating high efficiency in water use efficiency, excellent biomass production, late flowering, upright architecture, higher levels of steviol glycosides, and a more robust antioxidant system compared to other genotypes from the germplasm bank at the University of Córdoba [37,40], Montería, CO, Colombia (08 • 25 ′ 47 ′′ N; 75 • 53 ′ 24 ′′ W; 18 m.a.s.l.). Specifically, genotype L020 emerged as the frontrunner, displaying the highest content of stevioside and rebaudioside A, followed by genotype Morita II.…”

“…However, they also face the obstacle of lacking efficient seed propagation and multiplication systems. In light of these findings, this study has the main objective to contribute to the advancement of knowledge about Stevia tissue culture by establishing specific micropropagation protocols for three elite genotypes: L-020, L-102, and Morita II, originating from the Stevia segregating lines germplasm bank at the University of Córdoba [37,40]. This contribution aims to increase the availability of promising Stevia materials for tropical regions worldwide.…”