Alongamento e enraizamento in vitro de Helicônia (Heliconia latispatha Bentham cv. Orange Gyro) em função do fotoperíodo e da concentração de macronutrientes do meio de cultivo MS

Abstract

Heliconia latispatha is an ornamental plant adapted to the tropical climate, whose inflorescences are very exotic and with good post-harvest durability; is a species conventionally propagated vegetatively through its rhizomes. However, difficulties in large-scale production, seedlings restricted to certain times of the year, and phytosanitary problems make research related to alternative methods, such as in vitro cultivation, important for the ornamental plant sector. Even with tissue culture, especially in vitro propagation, having evolved in recent years, many studies still use patterns formulations for the culture media and standard photoperiods, which can lead to morphological and physiological problems in the development and growth of species that have very restricted mineral and photoperiodic requirements. The objective of this work was to evaluate the macronutrient concentrations of the culture medium for in vitro elongation and rooting from shoots of Heliconia latispatha Bentham cv. Orange Gyro in two photoperiods. The experiment was carried out with a completely randomized design in a factorial scheme, 4 x 2, with 4 macronutrient concentrations of MS medium, T1 (25%), T2 (50%), T3 (75%) and T4 (100%) and 2 photoperiods (12 hours and 16 hours of daily light), totaling 8 treatments. Six replicates (flasks) were used per treatment, the experimental unit consisting of a bottle containing 3 explants (shoots). The treatment with 75% of macronutrients in the photoperiod of 12 hours proved to be the most adequate for the elongation and rooting of micropropagated seedlings of Heliconia latispatha Bentram cv. Orange Gyro, in order to induce the highest averages of height, without compromising the fresh and dry masses of the seedlings, as well as the length of the longest root and the diameter of the pseudocaule, while also did not affect the production of leaves, the production of photosynthetic pigments and leaf thickness in relation to the treatments.