Metodologias para o cultivo in vitro de Eucalyptus pilularis Smith visando o resgate e a clonagem de plantas selecionadas

Abstract

The induction of epicormic shoots in pruned branches together with micropropagation can be used to promote tissue rejuvenation/reinvigoration and rescue adult eucalypts trees in tests of species and provenances with potential for industrial applications. Despite the inexpressive plantations in Brazil, the species Eucalyptus pilularis has great potential for sawmilling and laminating in the Southeast of the country. In vitro propagation of woody species, mainly with advanced ontogenetic age, still presents obstacles, making it necessary to define methodologies that promote improvements in the in vitro culture environment. Thus, the general aim of the work was to define methodologies to improve the morphophysiological responses in the establishment, multiplication, elongation and in vitro rooting of E. pilularis with a chronological age of 44-years-old, being divided into four chapters. In chapter 1, the aim was to evaluate two tissue origins and four inoculation methods in the in vitro establishment of the species. According to the results, it was only possible to establish explants from tissues with a lower ontogenetic age, and it is recommended to use activated charcoal, PVP30 and exposure to light in this phase of micropropagation for E. pilularis. For chapter 2, the aim was to evaluate induction of buds and epicormic shoots, establishment, multiplication by 15 subcultures, genetic fidelity and in vitro elongation, testing two concentrations of BAP and NAA, from three selected trees of the species (M1, M2 and M3). It was only possible to establish, multiply and elongate explants from M3, being recommended the concentration of 0.10 mg L-1 BAP combined with 1.0 mg L-1 NAA for in vitro elongation. Polymorphisms were not found after in vitro multiplication. The aim of the third chapter was to evaluate the effect of carbon sources on in vitro multiplication and elongation, and concentrations of the best carbon source and flask sealing systems on elongation and in vitro rooting of the species. The use of glucose promoted the best results on in vitro multiplication and elongation of shoots in tubes and the best in elongation and in vitro rooting in flasks containing lids with a porous membrane, at a concentration of 30 g L-1. In chapter 4, the objective was to evaluate the effect of light quality and glucose concentrations on the in vitro multiplication and elongation of the species. The use of fluorescent lamps and R:B LEDs and supplementation of the medium with 30 g L-1 of glucose resulted in the highest averages for the characteristics evaluated in multiplication and elongation in vitro. The methodologies tested demonstrate the possible improvements in the in vitro culture of E. pilularis with advanced ontogenetic age and the importance of applying cloning on a large scale, through the techniques used for eucalypts species.