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

Monique Cristine R Juras,Rosete Pescador,Vivian Tamaki,Wagner De Melo Ferreira,Jackeline Jorge,Rogério M Suzuki

doi:10.1590/2175-7860201970014

Abstract

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.

Highlights

Cattleya xanthina (Lindl.) Van den Berg is an endangered, epiphytic species that has been categorized as “under threat” by the Brazilian Ministry of the Environment (MMA 2014)
Experiment I After 180 days of culture (Fig. 1), the biometric parameters of Cattleya xanthina plants revealed that the greatest shoot length was obtained on Knudson C (KC) medium (1.4 cm)
There was no significant difference among the culture media in terms of shoot fresh mass (Fig. 2c), the best result was obtained on KC medium

Summary

Introduction

Cattleya xanthina (Lindl.) Van den Berg is an endangered, epiphytic species that has been categorized as “under threat” by the Brazilian Ministry of the Environment (MMA 2014). Previous studies related to other endangered orchids have demonstrated that the development of seedlings varies among species and is dependent, among other factors, on the culture medium (Dutra et al 2008; Suzuki et al 2009, 2010). According to Malavolta et al (1997), the chlorophyll content present in plant tissues indicates the level of nitrogen absorbed. As it makes part of the chlorophyll molecule, nitrogen is critical to plant growth and any deficiency affects light absorption during photosynthesis, negatively influencing plant development (Cheng 2003)

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