Stevia rebaudiana under a CO2 Enrichment Atmosphere: Can CO2 Enrichment Overcome Stomatic, Mesophilic and Biochemical Barriers That Limit Photosynthesis?

Due to the desire to live a healthier lifestyle, the search for nonglycosidic sweeteners has increased stevioside production in recent years. The main goal of this study was to demonstrate that S. rebaudiana grown in a CO2-enriched environment can overcome stomatic, mesophilic and biochemical barriers that limit photosynthesis (A(N)). We show that in an environment with a CO2-enriched atmosphere (800 and 1200 mu mol CO2 mol(-1)), the genotype 16 (G16) shows an increase of 17.5% in A(N) and 36.2% in stomatal conductance in plants grown in 800 mu mol CO2 mol(-1) when compared to non-enriched plants. In conjunction with this issue, the plants show an efficient mechanism of dissipating excess energy captured by the photosystems. Photosystem II efficiency was increased at 1200 mu mol CO2 mol(-1) when compared to non-enriched plants, both in genotype 4 (25.4%) and G16 (211%). In addition, a high activity of Calvin-Benson enzymes, a high production of sugars and an enhanced production of steviosides were combined with high horticultural yield. Both genotypes (G4 and G16) showed excellent physiological indicators, with high superiority in G16. Thus, our study has demonstrated that S. rebaudiana could adapt to global climate change scenarios with higher temperatures caused by higher atmospheric CO2.