Efeito do boro (H3 BO3) e manganês (MnSO4 .4H2 0) na micropropagação de Cattleya loddigesii Lindl. (Orchidaceae)

Abstract

The current work aimed at studying the effect of different concentrations of Boron (H3 BO3 ) and Manganese (MnSO4 .4H2 0) in the Knudson C (KC) medium on the in vitro culture of Cattleya loddigesii seedlings. Both Boron and Manganese are essential compounds required for the activity of several enzymes involved in respiration and/or photosynthesis. Seeds of C. loddigesii were in vitro germinated. After one month, shoots (1 to 1.5 cm in length) containing small roots (±0.5 cm) were excised and inoculated in 250 cm3 flasks containing 60 mL of the (KC) medium supplemented with H3 BO3 (0; 0.056; 1.4; 2.8 and 5.6 mg L-1) and MnSO4 .4H2 0 (0; 3.75; 7.5; 15 and 30 mg L-1 ) in all possible combinations. Additionally, this medium also contained 2 g L-1 of activated charcoal and 150 g L-1 of banana pulp (obtained from the local cv. “nanica”). After 90 days, the best in vitro growth of orchids seedlings was obtained with the KC medium with concentrations of 1.4 mg L-1 H3 BO3 and 15 mg L-1 MnSO4 .4H2 0.