Photoautotrophic potential and photosynthetic competence in Ananas comosus [L]. Merr. cultivar Turiaçu in in vitro culture systems

The Turiaçu pineapple cultivar produces fruits of high organoleptic value but has few biotechnological studies on seedling production. However, conventional in vitro propagation can affect the photosynthetic potential of plants when transferred to the field, thus mitigating measures should be undertaken to solve this limitation, for example by decreasing carbohydrate concentration in the growth medium, adopting bioreactors of temporary immersion with forced ventilation, and using gas permeable membranes in the culture flask. The present work focused on evaluating the growth and development of plantlets from Ananas comosus [L]. Merr. cultivar Turiaçu, an important but neglected pineapple cultivar, under different sucrose concentrations and cultivation systems. For that, the impact of the photomixotrophic and photoautotrophic growth on morphophysiological responses of plants and survival during the ex vitro acclimatization was assessed. The plants were grown in four cultivation systems: permanent immersion system with sealed flasks (PIS-SF); permanent immersion system with natural ventilation (PIS-NV); single-flask temporary immersion bioreactors (TIS-PF); and twin-flasks temporary immersion bioreactors (TIS-RALM), combined with sucrose concentrations (0, 5.0, 15.0, and 30.0 g L⁻¹). The results indicate that Turiaçu plants have photoautotrophic potential in vitro, as the photochemical efficiency of the plants increased in cultivation systems with TIS –RALM gas exchange without the addition of sucrose. Furthermore, it also improved the performance and hardening of plants in ex vitro conditions, which constitutes a crucial step towards the diffusion of this cultivar.