Open AccessFontes de nitrogênio no crescimento <em>in vitro</em> de plântulas de <em>Cattleya loddigesii</em> Lindl. (Orchidaceae)
Author(s) -
Aparecida Gomes de Araújo,
Moacir Pasqual,
Filipe Almendagna Rodrigues,
Janice Guedes de Carvalho,
Danielle Zampiere Arce Zárraga
Publication year - 2009
Publication title -
acta scientiarum. biological sciences
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.16
H-Index - 23
eISSN - 1807-863X
pISSN - 1679-9283
DOI - 10.4025/actascibiolsci.v31i1.309
Subject(s) - calcium nitrate , ammonium , laboratory flask , horticulture , sucrose , chemistry , nitrate , ammonium nitrate , calcium , botany , biology , food science , organic chemistry
Objetivou-se avaliar diferentes concentrações de nitrato de cálcio e nitrato de amônio no crescimento in vitro de orquídea. Plântulas de Cattleya loddigesii oriundas de sementes germinadas in vitro, com 1,0 cm de comprimento, foram inoculadas em frascos contendo 60 mL de meio de cultura WPM modificado em suas concentrações de nitrato de cálcio (0, 278, 556, 834 e 1112 mg L-1) e nitrato de amônio (0, 200, 400, 600 e 800 mg L-1). O meio foi acrescido de 20 g L-1 de sacarose, 150 g L-1 de polpa de banana ‘nanica’ madura e 2 g L-1 de carvão ativado, pH ajustado para 5,7 ± 0,1 e solidificado com 6 g L-1 de ágar, antes da autoclavagem a 121ºC e 1,5 atm, por 20 min. Após a inoculação, os frascos foram transferidos para sala de crescimento a 25 ± 2ºC, fotoperíodo de 16h e 35 µmol m-2 s-1 de intensidade luminosa. Decorridos 90 dias, observaram-se melhores resultados para número de folhas e de brotos com 400 e 450 mg L-1 de nitrato de amônio, respectivamente, enquanto que o maior número de raízes foi obtido com 600 mg L-1 de nitrato de amônio e 278 mg L-1 de nitrato de cálcio. Recomenda-se a utilização do meio WPM em sua composição original, sem nitrato de cálcio na micropropagação desta espécie. This work aimed to evaluate the effect of different concentrations of calcium and ammonium nitrate on the in vitro development of orchids. Cattleya loddigesii ‘Tipo’ orchid plantlets, 1.0 cm in size produced by self pollinization and also by in vitro germinated seeds, were inoculated in flasks containing 60 mL of WPM culture medium, modified with different concentrations of calcium nitrate (0, 278, 556, 834, and 1112 mg L-1) and ammonium nitrate (0, 200, 400, 600 and 800 mg L-1). The culture medium was supplemented with 20 g L-1 of sucrose, 150 g L-1 of ‘Nanica’ banana pulp, activated charcoal 2 g L-1, solidified with agar 6 g L-1, and pH adjusted to 5.7 ± 0.1 before being autoclaved at 121ºC, 1.5 atm pressure during 20 minutes. After inoculations, the flasks were transferred to a growth room with controlled temperature around 25±2ºC, 16 h photoperiod regime, with a light intensity of 35 µmol m-2 s-1. After 90 days, it was observed that the best results in terms of number of leaves was achieved with 400 mg L-1 of ammonium nitrate, and the highest number of sprouts was obtained with 450 mg L-1 of ammonium nitrate, but the major number of roots was verified in the treatment with 600 mg L-1 of ammonium nitrate and 278 mg L-1 of calcium nitrate. In resume, it is recommended to use the WPM medium in its original composition, without calcium nitrate to micropropagate Cattleya loddigesii ‘Tipo’ orchid plantlets. The best rooting was achieved with 600 mg L-1 of ammonium nitrate and 278 mg L-1 of calcium nitrate added in the medium