Efeito do fotoperíodo na morfofisiologia de abacaxizeiro cultivado in vitro em sistema fotomixotrófico

Abstract

Plants adjust their development to environmental variations through molecular mechanisms regulated by the circadian rhythm, with photoperiod being one of the main modulators of these processes. In this context, in vitro culture represents a strategic tool for investigating plant physiological plasticity and the interaction between photoperiod and the biological clock. In the state of Maranhão, the pineapple variety ‘Turiaçu’ shows agronomic potential, however, it faces limitations in the production of high-quality plantlets, making in vitro culture a viable alternative. Thus, this study aimed to evaluate the morphophysiological responses of pineapple plants from the ‘Pérola’ and ‘Turiaçu’ varieties cultivated in vitro under different photoperiods. The experiment was conducted in a completely randomized design, in a 2 × 4 factorial scheme, considering the two varieties and four photoperiods (4, 8, 16, and 24 h of light). Photoperiods of 8 and 16 h promoted greater root growth, leaf area expansion, biomass accumulation, and increased levels of photosynthetic pigments in both varieties, whereas the continuous 24 h photoperiod impaired growth and physiological efficiency, in addition to altering anatomical traits. It is concluded that intermediate photoperiods are the most suitable for the in vitro culture of the varieties studied, highlighting the central role of photoperiod in circadian regulation and plant morphophysiological plasticity