Efeito de GA3 e da condição de luminosidade no crescimento in vitro de Leptotes unicolor Barb.Rodr.

Abstract

This study aimed to evaluate the effect of GA3 concentrations (0, 1, 5, 10 or 20 mg L-1 ) and lighting condition (white, yellow, blue, red and green) on the in vitro growth of Leptotes unicolor Barb. Rodr. We used a randomized block design, and the treatments were arranged in a 5 x 5 factorial with three replications. Were used as explants plants of L. unicolor, with 1 cm of height, leaves and roots. The medium was MS 1⁄2 increased of GA3 doses and the cultures were placed in a growth room at 25 ± 2 o C, photoperiod of 12 hours and subjected to different light conditions, for 360 days when they were evaluated on the number of shoots and root, height, root length and fresh weight of the tussocks. There was joint effect of GA3 concentrations and light conditions on the variables studied, with the exception (p> 0.05) fresh mass tussocks, which showed overall average equal to 7.50 g, regardless of the combinations. The highest number of shoots (215) was observed in the calculated dose of 7 mg L-1 GA3 under yellow light. The highest number of roots (17) and the root system longer (15.1 mm) were observed in the presence of white light, the larger diameters of the tussocks (43.5 mm) were recorded under red light, regardless of the color of light the highest height of tussocks (32.5 mm) were observed in the absence of GA3 and lower (below 5 mm) at the highest dose studied. Leptotes unicolor Barb.Rodr. shows higher growth in vitro in the absence of GA3 and can be grown in bright white, yellow or red.