In vitro culture and acclimatization of Cattleya xanthina (Orchidaceae), an endangered orchid of the Brazilian Atlantic Rainforest

Abstract Cattleya xanthina is a Neotropical orchid endemic to the Brazilian Atlantic Rainforest, at high risk of extinction. In this paper, we investigated the effects of different culture media on C. xanthina as well as on their endogenous nitrogen status. Culture media studied: Knudson C (KC), Vac...

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Bibliographic Details
Published in:	Rodriguésia Vol. 70
Main Authors:	Juras, Monique Cristine R., Jorge, Jackeline, Pescador, Rosete, Ferreira, Wagner de Melo, Tamaki, Vivian, Suzuki, Rogério M.
Format:	Journal Article
Language:	English
Published:	Instituto de Pesquisas Jardim Botânico do Rio de Janeiro 2019
Subjects:	Auxin conservation cytokinin ex vitro nitrogen
Online Access:	Get full text
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Summary:	Abstract Cattleya xanthina is a Neotropical orchid endemic to the Brazilian Atlantic Rainforest, at high risk of extinction. In this paper, we investigated the effects of different culture media on C. xanthina as well as on their endogenous nitrogen status. Culture media studied: Knudson C (KC), Vacin and Went (VW), and Murashige and Skoog (MS), the latter used at two different concentration (full and half-strength; MS/2). After 180 days, plants were transferred to MS medium with different NAA and BA concentrations. In each treatment, biometric parameters were measured and the endogenous levels of photosynthetic pigments, total protein, nitrate and ammonium ions were quantified. Plants grown on KC medium had the lowest concentration of nitrogen but exhibited the greatest shoot development, production of photosynthetic pigments and total protein. Results of growth regulators showed that the highest concentration of auxin stimulated root development and the production of photosynthetic pigments, and that a higher concentration of cytokinin promoted protein synthesis and the development of shoots. Most successful acclimatization was obtained when a mixture of Sphagnum and Pinus bark was used as the substrate. Resumo Cattleya xanthina é uma orquídea neotropical endêmica da Mata Atlântica brasileira, com alto risco de extinção. Neste trabalho analisamos diferentes meios de cultura sobre o desenvolvimento de C. xanthina, e seu status de nitrogênio endógeno. Meios de cultura estudados: Knudson C (KC), Vacin & Went (VW) e Murashige & Skoog (MS), e o meio MS com metade da concentração de nutrientes (MS/2). Após 180 dias, as plantas foram transferidas para o meio MS com diferentes concentrações de NAA e BA. Em cada tratamento, foram analisados parâmetros biométricos e níveis endógenos de pigmentos fotossintéticos, proteína total, nitrato e íons de amônio. As plantas cultivadas em meio KC apresentaram menor concentração de nitrogênio, mas exibiram o maior desenvolvimento, produção de pigmentos fotossintéticos e proteína total. Os resultados dos reguladores de crescimento mostraram que a maior concentração de auxina estimulou o desenvolvimento radicular e a produção de pigmentos, e a maior concentração de citocinina promoveu síntese proteica e o desenvolvimento caulinar. A aclimatização mais bem sucedida foi obtida quando uma mistura de Sphagnum e casca de Pinus foi usada como substrato.
ISSN:	0370-6583 2175-7860 2175-7860
DOI:	10.1590/2175-7860201970014