Resumo Cattleya cernua é uma orquídea epífitica nativa da Floresta Atlântica, do Cerrado, da Caatinga e do Pampa. Visando ao desenvolvimento de uma ferramenta tecnológica in vitro para a conservação, plantas foram micropropagadas por meio da cultura assimbiótica, e a influência de diferentes concentrações de sacarose (10, 30, 60 e 90 g L-1) e macronutrientes (25, 50 e 100% MS) sobre a sobrevivência e o desenvolvimento das plantas foi avaliada. A sobrevivência das plantas variou entre 47 e 100%. A interação entre macronutrientes e sacarose influenciou o desenvolvimento das plantas. O sistema aéreo das plantas foi superior no meio 100% MS, combinado com 30 ou 60 g L-1 de sacarose. O número de raízes foi superior com macronutrientes reduzidos, combinados com 30 ou 60 g L-1 de sacarose. O comprimento da maior raiz também foi superior quando os macronutrientes foram reduzidos, mas combinados com 10 ou 30 g L-1 de sacarose. A maior massa foi registrada quando 30 g L-1 de sacarose foram adicionados às três concentrações de sais. A clorofila não diferiu entre plantas crescidas com 30 ou 90 g L-1 de sacarose. Nós recomendamos cultivar as plantas em meio MS com 30 g L-1 de sacarose para melhor desenvolvimento do sistema aéreo. C. cernua pode ser micropropagada assimbioticamente, facilitando estratégias de conservação ex vitro.

Abstract Cattleya cernua is an epiphytic orchid native of the Atlantic Forest, Cerrado, Caatinga and Pampa. Aiming at the development of an in vitro conservation technology, plants were micropropagated through asymbiotic culture and the influence of different concentrations of sucrose (10, 30, 60 and 90 g L-1) and macronutrients (25, 50 and 100% MS) on survival and development was evaluated. Plant survival ranged between 47 and 100%. The interaction between macronutrients and sucrose influenced plant development. The aerial system of the plants was higher in 100% MS medium combined with 30 or 60 g L-1 of sucrose. The number of roots was higher with reduced macronutrients, combined with 30 or 60 g L-1 of sucrose. The length of the largest root was also higher when macronutrients were reduced but combined with 10 or 30 g L-1 of sucrose. The greatest mass was recorded when 30 g L-1 of sucrose was added to the three salt concentrations. Chlorophyll did not differ between plants grown with 30 or 90 g L-1 of sucrose. We recommend cultivating the plants in MS medium with 30 g L-1 of sucrose for better development of the aerial system. C. cernua can be asymbiotically micropropagated, facilitating ex vitro conservation strategies.

Resumo As características das cascas de árvores hospedeiras podem influenciar na distribuição e no desenvolvimento de epífitos. Amostras de casca foram suspensas em 10 e 20 mL de água destilada por 1, 4 e 24 h, para avaliação de métodos para a determinação do pH. Cascas de Myrcia brasiliensis, M. glabra e Myrsine coriacea hospedeiras de Cattleya intermedia foram coletadas no fuste e na copa, para avaliação do pH, da capacidade de retenção de água e da espessura. A altura da parte aérea e o número de raízes de C. intermedia crescidas no fuste e na copa das três espécies de árvore foram avaliados. O volume de solvente e o tempo de suspensão da casca influenciaram nos valores de pH. O pH e a espessura da casca de Myrsine coriacea foram maiores do que nas espécies de Myrcia. A altura da parte aérea e o número de raízes dos indivíduos de C. intermedia foram superiores na copa. Os parâmetros de crescimento das plantas não se relacionaram com o pH e a espessura da casca. Os dados trazem informações para subsequentes estudos sobre epífitos vasculares que incluam novos parâmetros e maiores amostragens, visando a subsidiar propostas de conservação de espécies ameaçadas.

Abstract The traits of the bark of host trees can influence the distribution and development of epiphytes. Bark samples were suspended in 10 and 20 mL of distilled water for 1, 4 and 24 h, to evaluate pH determination methods. Bark samples of Myrcia brasiliensis, M. glabra and Myrsine coriacea, three host trees of Cattleya intermedia had bark samples collected from the trunk and the crown, for the evaluation of the pH, water retention capacity and thickness. Shoot height (cm) and number of roots of C. intermedia grown on trunk and into the crown of the three species were evaluated. Volume of solvent and suspension time of the bark samples influenced pH values. The pH and thickness of Myrsine coriacea barks were higher when compared to Myrcia species. Shoot height and number of roots of C. intermedia individuals were significantly higher in the crown. The growth parameters of the reintroduced plants were unrelated to pH and bark thickness. The data bring information for the application of further vascular epiphyte studies including new parameters and greater samplings, in order to support proposals of the conservation of endangered species.

ABSTRACT Biotic and abiotic factors, such as luminosity, temperature, air humidity, and herbivory, can affect the establishment of reintroduced plants in natural habitats. This study evaluated the effects of these factors on the survival and growth of Cattleya intermedia plants reintroduced into a forest fragment in South Brazil. Plants of C. intermedia were obtained from in vitro seed germination in asymbiotic culture. Eighty-eight plants were reintroduced at both the forest edge and forest interior. Plants with greater shoot heights and number of leaves and pseudobulbs suffered more damage from herbivores at the edge. There were no significant differences in morphometric parameters between damaged and non-damaged plants in the interior. Tenthecoris bicolor, Helionothrips errans, Ithomiola nepos, Molomea magna and Coleoptera larvae damaged C. intermedia. Luminosity was higher at the edge, while air humidity and temperature were the same in both environments. Herbivory associated with abiotic factors increased plant mortality in the interior, while abiotic factors were determinative of plant survival at the edge. Luminosity is important to the survival of reintroduced epiphytic orchids, and herbivory affects the success of reintroduction.

Resumo A cultura in vitro é uma ferramenta eficiente para a propagação de plantas de importância ecológica e econômica e permite o entendimento acerca de aspectos ecofisiológicos das espécies. Este estudo teve por objetivo avaliar a influência de diferentes concentrações de macronutrientes sobre o desenvolvimento in vitro e a sobrevivência ex vitro de plântulas de Vriesea incurvata, visando à conservação desta bromélia epifítica endêmica da Floresta Atlântica. A germinação in vitro foi avaliada aos 60 dias e as plântulas foram cultivadas por 180 dias em meio MS com 25 ou 50% dos macronutrientes, 25 ou 50% dos sais nitrogenados, bem como com 100% da formulação original do meio. As sementes apresentaram 95% de germinação. Em todos os tratamentos, houve 100% de sobrevivência das plântulas cultivadas in vitro. A redução de todos os macronutrientes ou dos sais nitrogenados mostrou-se benéfica, proporcionando maior comprimento da parte aérea e da raiz maior, maior número de folhas e de raízes, bem como maior massa fresca, além de ter propiciado 97% de sobrevivência das plântulas aclimatizadas ex vitro. Os dados obtidos permitem o estabelecimento de um protocolo de propagação in vitro de V. incurvata, com o objetivo de sua futura reintrodução no habitat natural.

Abstract In vitro culture is an efficient tool for the propagation of plants of ecological and economic importance and allows the understanding about ecophysiological aspects of the species. The objective of this study was to assess the influence of different macronutrient concentrations on in vitro development and ex vitro survival of Vriesea incurvata plantlets, aiming the conservation of this endemic epiphytic bromeliad from the Atlantic Forest. The in vitro germination was assessed at 60 days and the plantlets were cultivated for 180 days on MS medium with 25 or 50% of the macronutrients, 25 or 50% of the nitrogen salts, or with 100% of the original formulation of the medium. The seeds showed 95% germination. In all treatments, there was 100% survival of in vitro cultivated plantlets. The reduction of all macronutrients or of the nitrogen salts was beneficial, and permitted a greater length of the aerial part and of the major root, a higher number of leaves and roots, and more fresh mass, as well as allowed 97% survival of ex vitro acclimatized plantlets. The obtained data allow the establishment of a protocol for in vitro propagation of V. incurvata, aiming its future reintroduction into the natural habitat.

ABSTRACTCattleya intermediais an Atlantic Forest species endemic to Brazil that is classed as vulnerable on the list of threatened species. In this study, C. intermedia plantlets were micropropagated in an asymbiotic culture and the influence of different concentrations of sucrose (15, 30, 45 and 60 g L-1, plus a zero sucrose medium) and macronutrient salts (complete Murashige and Skoog (MS) medium and half MS medium (with half-strength macronutrients)) on survival and development of the plantlets was evaluated. In all treatments 100% plantlet survival was achieved. The integrated analysis of height of aerial part, number of leaves per plantlet, fresh mass, number of roots per plantlet and length of the longest root showed that the plantlets exhibited greatest development at the half-strength macronutrient concentrations with 45 or 60 g L-1 of sucrose, as well as at the complete macronutrient concentration with 60 g L-1 of sucrose. Plantlets acclimatized and reintroduced to an environment in which the species occurs naturally exhibited 98.6% survival. The results obtained in this study allowed the establishment of optimal conditions for asymbiotic micropropagation, which is a requisite for future studies focused on conservation of C. intermedia.

Anathallis adenochila is a small epiphytic orchid, endemic to the Atlantic Forest in the southern and southeastern regions of Brazil. Information on the species is scarce and limited to distribution and occurrence data, with no reports about its development. In the present study, plantlets were propagated in vitro, and the influence of different concentrations of macronutrient salts and sucrose on the survival and development of the species was assessed. The analysis were performed on complete Murashige and Skoog (MS) medium and half MS medium (with half-strength macronutrients) containing 10, 30 or 60 g L-1 of sucrose. Plantlet survival, height of the aerial part, and the length of the longest root were significantly greater on half MS medium containing 30 or 60 g L-1 of sucrose. The number of leaves per plantlet was higher in the presence of 60 g L-1 of sucrose, regardless of macronutrient concentration, and the highest number of roots was observed in plantlets cultured on half MS medium with 60 g L-1 of sucrose. This first report of Anathallis adenochila in vitro propagation may contribute to future studies on the physiological and ecological aspects of the life cycle of this species.

Ramos de Tradescantia pallida var. purpurea contendo botões florais são utilizados em bioensaios para diagnosticar efeitos genotóxicos de água. Diferentes substâncias para adaptar e recuperar os ramos antes e após a exposição a amostras de água e diferentes tempos de exposição são relatados na literatura. O objetivo do estudo foi avaliar e comparar as frequências de micronúcleos (MCN) em T. pallida quando ramos com botões florais foram submetidos a diferentes condições metodológicas. O bioensaio foi então aplicado bimensalmente durante sete meses para avaliar o potencial genotóxico de um sítio do Rio dos Sinos em Campo Bom, Rio Grande do Sul, Brasil. As frequências de MCN em botões de ramos adaptados e recuperados em água destilada e em solução de Hoagland foram de 3,0 e 2,9, respectivamente, quando ramos foram expostos a água do rio e de 1,19 e 1,23 nos controles. Não foram observadas diferenças significantes entre frequências de MCN em ramos expostos por 8, 24 ou 32 h a água do rio (de 3,07 a 4,73) e nos controles (de 1,13 a 2,00) em todas as amostragens ao longo do ano. Adaptação e recuperação de ramos em água destilada ou solução de Hoagland e exposição durante diferentes tempos não influenciaram a resposta de T. pallida de formas diferentes, indicando que todas as condições testadas são viáveis para biomonitoramento de genotoxicidade de água. Amostras de água do Rio dos Sinos apresentaram genotoxicidade ao longo do período monitorado, evidenciada pelas frequências de MCN registradas, que foram significativamente superiores às dos controles.

Tradescantia pallida var. purpurea cuttings with flower buds are utilized in bioassays to diagnose genotoxic effects of water. The literature describes different substances used to adapt and recover the cuttings before and after exposure to water samples and also describes the effects of different exposure times. This study evaluated and compared the micronuclei (MCN) frequencies in T. pallida when cuttings with flower buds were submitted to different methodological conditions. The bioassay was then applied bimonthly during seven months to assess the genotoxic potential of a site located on the Sinos River in Campo Bom, Rio Grande do Sul, Brazil. Micronuclei frequencies in buds of cuttings adapted and recovered in distilled water and in Hoagland solution were 3.0 and 2.9, respectively, for cuttings exposed to river water, and 1.19 and 1.23 in controls. No significant differences among MCN frequencies were observed when cuttings were exposed for 8, 24 or 32 hours to river water (from 3.07 to 4.73) and in controls (from 1.13 to 2.00) in all samplings during a year. Adaptation and recovery of cuttings in distilled water or Hoagland solution and exposure for different times did not influence the response of T. pallida, indicating that all the conditions tested are viable for biomonitoring of water genotoxicity. Water samples from the Sinos River presented genotoxicity during the period monitored, evidenced by the MCN frequencies recorded which were significantly higher than the frequencies of the controls.