n vitro conservation and acclimatization of Epidendroideae (Orchidaceae) from Sergipe, Brazil

Abstract

Orchids are known for the beauty, exuberance, and color of their flowers and therefore represent one of the most coveted ornamental plants. Due to their high commercial value, several illegal practices of removal and commercialization have led to the verge of extinction. This study aimed to develop protocols for in vitro conservation under slow growth and acclimatization of species of the subfamily Epidendroideae (Orchidaceae), from the state of Sergipe, Brazil. Two experiments were conducted: the first one tested four concentrations of MS (MURASHIGE and SKOOG, 1962) (25%, 50%, 75%, 100%), three orchid species (Catasetum macrocarpum, Oeceoclades maculata, and Polystachya estrellensis), and two temperatures (18 and 25ºC); the second one tested three combinations of carbon sources and osmotic regulators (20 g L -1 sucrose; 10 g L -1 sucrose + 5 g L -1 de mannitol; 10 g L -1 sucrose + 5 g L -1 sorbitol) and the same three species and two temperatures. For the in vitro conservation of C. macrocarpum, O. maculata, and P. estrellensis over 450 days, the use of 25% of MS salts or 20 g.L -1 sucrose at 25ºC is recommended. C. macrocarpum seedlings were acclimatized using sand + shredded pine bark + worm castings at a ratio of 2:2:1 (w:w:w). The use of sand alone is recommended for the acclimatization of O. maculata.

Germinación asimbiótica, conservación ex situ e in vitro regeneración de plantas de Catasetum integerrimum Hook

“…The conservation protocols for Dendrobium draconis, Bulbophyllum auricomum Lindl., Ullucus tuberous species of the subfamily Epidendroideae, Arnica montana L. used MS reduced to half its ionic strength as basal medium (Than, 2013;Hammond Hammond et al, 2019;Menezes-Sá et al, 2019;Petrova et al, 2021).…”

“…The woody plant medium (WPM) (Matos Alvim et al, 2020). Culture media for slow growth can use sucrose as a carbon source (Than, 2013;Sanghamitra et al, 2019;Menezes-Sá et al, 2019;El-Hawaz et al, 2019;Matos Alvim et al, 2020;Gomes et al, 2021). Another modification made to the culture medium is sorbitol and mannitol as carbon sources.…”

Germination and initial development in vitro, and acclimatization of Oeceoclades maculata (Orchidaceae), aiming at its reintroduction in natural environments

“…As their leaves are coriaceous, they are less susceptible to water loss which certainly aids survival, especially under controlled environmental and growth conditions such as the ones to which O. maculata plants were subjected in the present study. Upon studying the effects of different substrates, Menezes et al (2019) verified that survival of O. maculata plants varied from 83 to 100% after 6 months of growth under shade-house conditions with 50% retention of solar radiation flux and an intermittent spray system (second acclimatization phase). The fact that shading percentage was higher (75%) might have contributed to the maximum survival of O maculata in the present study.…”

“…As the leaves of this species are much thinner and thus more prone to water loss than those of O. maculata, the observed survival percentage at the end of the second phase was much lower. These results obtained for O. maculata might also have resulted from the fact that this orchid species is terrestrial and adapted to different substrates varying from sandy to clayey ones (Menezes et al, 2019).…”

Adequação das condições de crescimento mínimo para a conservação in vitro de Vernonia condensata

“…mucugensis), observaram que as maiores médias para o número de folhas verdes foram obtidas na temperatura de 18 ºC, independente da concentração de carboidrato utilizado. Assim como os autores supracitados, Menezes- Sá et al (2019), ao compararem duas temperaturas de cultivo (18 e 25 ºC), observaram que a temperatura de 18 ºC proporcionou maiores médias atribuídas ao número de folhas verdes na conservação in vitro das espécies Polystachya estrellensis Rchb. f. e Oeceoclades maculata (Lindl.)…”