Tecnologia LED e diferentes meios de cultura na germinação assimbiótica e crescimento inicial in vitro de Ionopsis utricularioides (Sw.) Lindl.

Abstract

The objective of this work was to evaluate the effect of light conditions provided by LEDs and to compare the efficiency of culture media on the in vitro germination and initial growth of Ionopsis utricularioides (Sw.) Lindl. For germination of I. utricularioides seeds, the culture media MS, ½ MS, K, VW were used, and media modified by replacing the original formulation VW macronutrients in commercial formulations for NPK: 09-45-15 (PF). or 20-20-20 (PM) or 30-10-10 (PC). After inoculation, the cultures were conditioned in growth room with controlled temperature and photoperiod, and subjected to the following conditions: white fluorescent (6.500K) - control; 100% yellow LED (3.000K); 100% white LED (6.500K); 50% white LED (6.500K) + 25% red + 25% blue. At 45 and 90 days after sowing, germination and initial growth were evaluated. At 45 days the highest percentage of germination was observed with the use of VW medium and most of the propagules were still in stage 1. When the medium K + LED 100% yellow (3.000K) was used the formation of seedlings at stadium 2. At 90 days the highest values for percentage of chlorophyll propagules were observed in MS, ½ MS and VW media, regardless of the light condition used. The highest values for stage 4 propagules were found in VW + 100% yellow (3.000K) LED and VW + CL4 50% white (6,500K) + 25% red + 25% blue. The I. utricularioides germinates and develops best when grown in vitro using culture media that have lower salt concentrations. The 100% yellow (3.000K) LED light source can be used in growing rooms for in vitro cultivation of this orchid.