Efeito de diferentes concentrações de sacarose e tipos de vedação no cultivo in vitro e no enraizamento ex vitro de Teca (Tectona grandis L.f.)

Abstract

Teak (Tectona grandis L.f.) is an exotic species of high commercial value worldwide. The importance of carbohydrates in both in vitro and in issuing and root formation and is currently being discussed. The objective of this study was to test the effect of different concentrations of sucrose and seal types on in vitro and ex vitro rooting of teak. The experiment was conducted in two stages: laboratory and nursery. In the laboratory Bioteca (Várzea Grande - MT), the explants were cultured on MS medium and maintained for 35 days in a growth chamber at a temperature of 30 +2 °C and a photoperiod of 16 h. The experimental design was completely randomized factorial 2 x 6, two types of seal (lid and cover with filter without filter) and six concentrations of sucrose (0, 6, 12, 18, 24 and 30 mg.L-1), twelve treatments with ten replicates each. We evaluated the following variables: length (cm), number of internodes and dry weight (mg) of shoots. In the nursery (Jangada-MT), the microcuttings had their bases immersed in the solutions, and then were planted in tubes with the base substrate of pine bark bioestabilizada. The experimental design was completely randomized in a factorial 2 x 2 x 5, considering the two forms of in vitro culture (C1 and C2), the presence and absence of sucrose, and the five IBA concentrations (0,0; 0,5; 1,0; 1,5 and 2,0 mg.L-1), totaling twenty treatments with six replications. The experiment was divided into three phases: a greenhouse, shade and full sun. Were evaluated: shoot length (cm), diameter (cm) and fresh weight (mg). The best results were obtained in the laboratory using the filter cover. For length at a concentration of 17 mg.L-1 of sucrose, with 4,1 cm length. For the number of internodes, with 18 mg L-1 sucrose, the average was 4,6 internodes. For the dry matter concentration of 30 mg L-1, with 0,0162 mg. In the nursery there was an interaction between culture and sucrose only in the greenhouse (first test) for the three variables. The IBA concentration showed no difference between the evaluations and the use of sucrose was shown to be necessary especially when there was a reduction in vitro.