Germinação, crescimento e desenvolvimento in vitro de orquídeas (Cattleya spp., Orchidaceae)

Abstract

Germination, growth and development in vitro of orchids of the genus CattleyaOrchids are over-exploited in their natural environment due to their ornamental importance, which is leading some species to extinction. In vitro culture is an alternative for ex-situ conservation. Our objective was to determine an efficient medium for in vitro seed germination and initial seedling growth of Cattleya forbesii and Cattleya harrisoniana. Seeds of Cattleya forbesii were incubated in Murashige & Skoog (MS) medium (T1) and MS added with 2,5 g L -1 of activated charcoal (T2). For the last, plants with 1 ± 0,2 cm of height were submitted to the following treatments: T1, T2, MS reduced to the half strenght (T3) and MS reduced to the half strenght supplemented with 1,25 g L -1 of activated charcoal (T4). Thirty days after seed inoculation of C. forbesii, it was verified 45% and 90% of germination in T1 and T2, respectively. The addition of activated charcoal also promoted an increase in the height of the C. forbesii seedlings Germinação, crescimento e desenvolvimento in vitro de orquídeas (Cattleya spp., Orchidaceae)As orquídeas no ambiente natural sofrem exploração devido a sua importância ornamental, levando algumas espécies à extinção. O cultivo in vitro é uma forma alternativa para a conservação ex-situ. Procurou-se determinar um meio de cultura eficiente para a germinação in vitro de sementes e o crescimento inicial de plântulas de Cattleya forbesii, bem como para o crescimento de plântulas in vitro de Cattleya harrisoniana. No primeiro caso, sementes foram inoculadas em meio de cultura básico de Murashige & Skoog (MS) = T1 e MS básico acrescido de 2,5 g L -1 de carvão ativado (CA) = T2. No segundo, plântulas com 1 ± 0,2 cm de altura foram submetidas aos tratamentos T1, T2, MS com a metade da concentração original de macro-micronutrientes (T3) e MS com a metade da concentração original de macro-micronutrientes suplementado com 1,25 g L -1 de CA (T4). Verificou-se aos 30 dias em C. forbesii uma porcentagem de germinação de 45% em T1 e 90% em T2. A adição de CA ao meio de cultura trouxe aumento na altura de plântulas de C. forbesii de acordo com análises realizadas aos 180 dias de cultivo. Em relação ao crescimento de C. harrisoniana, aos 240 dias observou-se que todos os parâmetros médios avaliados (altura da parte aérea, massa de matéria fresca total, número de raízes e folhas, comprimento da maior raiz e diâmetro do pseudocaule) foram significativamente maiores em T2. Dessa forma, sugere-se o uso do meio MS acrescido de 2,5 g L -1 de CA (T2), uma vez que é significativamente favorável tanto para a germinação de sementes quanto para o crescimento de ambas as espécies.Palavras-chave: carvão ativado, meio de cultura, micropropagação, orquídeas.

In vitro establishment and early development of barueiro (Dipteryx alata Vogel)

“…Given the efficiency of activated carbon to adsorb undesirable compounds, which are occasionally present in the medium, it follows that it also acts on the desirable substances, making them unavailable for the explant, indicating there is a tolerable limit for this agent to the culture medium. The optimal dose in this study was approximately 2,5 g L -1 , a result that corroborates those found by Chagas et al (2005) and Schneiders et al (2012) who worked with Cattleya harrisoniana and several species of citrus, respectively. An adequate supply of activated charcoal is an essential requirement for the satisfactory performance of explants in vitro.…”

In vitro propagation of Cyrtopodium saintlegerianum rchb. f. (orchidaceae), a native orchid of the Brazilian savannah

“…This percentage was significantly higher than that found on AC-devoid medium (30%) ( Table 1). Similar results were found by Schneiders et al (2012), who obtained that, at 30 days after sowing, both treatments had germinated; however, the medium containing AC promoted higher germination of seeds (90%) compared to that with no AC (45%). Thomas (2008) affirmed that not all species undergo positive influence by the presence of AC; therefore, to establish a suitable protocol for each kind of orchid, specific tests are necessary.…”

PYROLIGNEOUS LIQUOR EFFECT ON IN AND EX VITRO PRODUTION OF Oeceoclades maculata (Lindl). Lindl.1

“…Plant structural development is directly related to absorption and incorporation of mineral nutrients (SCHNEIDERS et al, 2012). Macro and micronutrient availability in pyroligneous liquor (Table 1) may have contributed to vegetative growth when present in the culture medium at low levels.…”