Fontes de luz na germinação assimbiótica e estabelecimento inicial in vitro de Schomburgkia crispa Lindl.

Abstract

This work was developed with the objective of evaluating the effect of different lights sources on germination and initial establishment in vitro of Schomburgkia crispa Lindl. Seeds from mature fruits of S. crispa were used, which were evaluated for viability by tetrazolium test, and dried in silica gel for 14 days. MS 1⁄2 was used as culture media for seed germination. After sowing in the aseptic environment, five culture flasks were brought to the greenhouse (235μmol m-2 s-1). The remaining treatments were conditioned in a growth chamber with controlled temperature and photoperiod (25 ± 2 °C; 16h) under the following light conditions: yellow LED 3000K (128 μmol m-2 s-1), weak white LED 6500K (58 μmol m-2 s-1), strong white LED 6500K (108 μmol m-2 s-1) and white fluorescent lamp 6500K (23 μmol m-2 s-1), used as control. Thereafter 45 and 90 days of sowing, germination and the initial establishment were evaluated. The experimental design was completely randomized with five replications. At 45 days after sowing, the conditions of natural light, white fluorescent lamp and LEDs: weak white and strong white had no effect on the germination of S. crispa, and provided protocormos only at stage 1. Seedlings at stage 2 were found under conditions of yellow LED light and white fluorescent lamp. At 90 days after sowing, there was also no statistical difference for the light conditions on the germination’s percentage. The yellow LED and the white fluorescent lamp presented better conditions for initial establishment of seedlings at stage 4. The use of yellow LED for in vitro cultivation of S. crispa provided greater differentiation of the propagules in a shorter period and lower seedlings mortality compared to the others sources of light.