Estratégias biotecnológicas com biorreator de imersão temporária e bioestimulantes para o cultivo in vitro de Cattleya nobilior Rchb.f.

Abstract

The Orchidaceae family has great representativeness in the Brazilian Cerrado; however, the beauty and diversity of its flowers make several species vulnerable to predatory collection. Among them, Cattleya nobilior stands out due to its high ornamental value and the risk of population reduction resulting from extractivism. An efficient strategy to reduce this vulnerability is the development of commercial production protocols associated with ex situ conservation through in vitro cultivation. Thus, the objective was to evaluate micropropagation techniques using biostimulants and different cultivation systems to optimize the growth of C. nobilior. To achieve this objective, two independent experiments were conducted. In both experiments, in vitro growth of the species was evaluated, with plants cultivated in two systems: conventional system (SCC) and temporary immersion bioreactor (BIT), and subjected to different concentrations of biostimulants: 1) Moringa oleifera (0; 12.5; 25.0; 37.5 and 50 g L⁻¹) and 2) Chlorella sp. (0.0; 0.15; 0.30; 0.45; 0.60 g L⁻¹). After 90 days, the plants were evaluated for in vitro vegetative growth. The experiments were arranged in a completely randomized design in a 2 × 5 factorial scheme (two micropropagation systems and five biostimulant concentrations), with four replications. In experiment 1, the TIB showed superior performance compared to the conventional cultivation system for most growth characteristics, highlighting the concentrations of 37,5 and 50 g L⁻¹ of M. oleifera, which promoted increases in the number of leaves, total length, and root length. In experiment 2, the concentrations of Chlorella sp. did not favor plant growth; however, they increased the number of shoots and leaves, indicating differentiated responses among vegetative organs and evidencing its use for species conservation and multiplication. Overall, the experiments demonstrate that the temporary immersion bioreactor is an efficient technology for in vitro cultivation of C. nobilior, providing greater growth and plant vigor. In addition, both Moringa oleifera and Chlorella sp. show potential as bio-inputs, provided they are applied at concentrations appropriate to the physiological needs of each species. Thus, their use associated with TIB constitutes promising strategies for commercial production and ex situ conservation of C. nobilior.