Optimizing nutrient solution for vegetative growth of Dendrobium Tubtim Siam and Phalaenopsis Taisuco Swan through plant tissue nutrient balance estimation.

BACKGROUND: Orchids are grown without soil in many regions of the world, but there is a lack of studies to define the balanced and adequate nutrient solution for their cultivation, mainly in the vegetative growth phase. Therefore, this paper aims to evaluate the optimal concentration of the nutrient solution based on the proposal by Hoagland and Arnon (1950) in the vegetative growth phase capable of increasing the nutrient contents, growth, and dry matter production of Dendrobium Tubtim Siam and Phalaenopsis Taisuco Swan. In addition, this paper aims to estimate a new nutrient solution from the optimal nutrient contents in the dry matter of these orchid species to be used in the vegetative growth phase. RESULTS: Nutrient contents, growth, and dry matter production increased as the nutrient solution concentration increased up to an average concentration of 62 and 77% for D. Tubtim Siam and P. Taisuco Swan, respectively. We found that the Hoagland and Arnon solution presented a group of nutrients with concentrations above the requirement for P. Taisuco Swan (nitrogen, phosphor, calcium, and sulfur) and D. Tubtim Siam (phosphor, calcium, magnesium, and sulfur), while other nutrients in the solution did not meet the nutritional demand of these orchid species, inducing nutritional imbalance in the vegetative growth phase. CONCLUSION: We conclude that using a balanced nutrient solution created specifically for each orchid species in vegetative growth might favor their sustainable cultivation by optimizing the use of nutrients in the growing medium.

Impact of Nitrate and Ammonium ratio on Nutrition and Growth of two Epiphytic Orchids.

Phalaenopsis and Dendrobium do not grow and flower well with 100% ammonium (NH4-N); and there are detailed studies on the effects of nitrate (NO3-N) and ammonium ratios on the flowering, but no information about accumulation of other nutrients and the effects of ammonium toxicity on orchids. For this reason, two experiments were carried out with orchids: Phalaenopsis 'Golden Peoker' and Dendrobium 'Valentine'. Six months after acclimatization the plants were transplanted to individual plastic vessels and the treatments consisted of five ratios (%) of nitrate / ammonium (0/100, 25/75, 50/50, 75/25, 100/0). The sources of NO3-N and NH4-N were calcium nitrate and ammonium sulfate, respectively. After 12 months treatment, when the plants were beginning to issuance of flower stem, the accumulation of: N, P, K, Ca and Mg in the shoot and biometric variables were evaluated for both species. The NH4-N ratio of 40% and 50% of the total nitrogen benefited the growth of Phalaenopsis and Dendrobium, respectively. The application of higher proportions of ammonium resulted in decreased N, K, Ca and Mg absorption, index of green color and increased leakage of electrolytes in Phalaenopsis and Dendrobium. NH4-N proportions greater than 75% for 12 months caused toxicity in Phalaenopsis and Dendrobium.

Carbohydrates on the growth of Cattleya schilleriana Reichb.f. seedlings (Orchidaceae) / Carboidratos no crescimento de plântulas de Cattleya schilleriana Reichb.f. (Orchidaceae)

ABSTRACT: The aim of the present study was to evaluate the effects of carbohydrate supplementation on the propagation of the orchid Cattleya schilleriana. The 120-d-old seedlings were subcultured in fructose-, glucose-, or sucrose-supplemented (0, 15, 30, and 45g L-1) ½ MS culture medium (half-strength macronutrient concentrations), using a completely random design with four repetitions per treatment. After 120d of treatment, root number and length, leaf number and length, and fresh weight were evaluated, and seedling survival was evaluated after 75d of acclimatization in a greenhouse. The in vitro growth data were submitted to regression analysis, whereas the percentage survival data were analyzed using ANOVA and Tukey's test. Both in vitro growth and ex vitro survival were lowest when the plantlets were grown in the absence of a carbohydrate source and highest (>90% survival) when supplemented with glucose. According to our findings, the addition of either glucose (30g L-1) or sucrose (30g L-1) is recommended for mass propagation of C. schilleriana.

RESUMO: O objetivo deste estudo foi avaliar a adição de doses de carboidratos em meio de cultura ½ MS para a propagação da orquídea Cattleya schilleriana. Plântulas com 120 dias após semeadura foram recultivadas em 12 tratamentos, onde foram investigadas a adição de diferentes doses de frutose, glicose e sacarose (0, 15, 30 e 45g L-1). O delineamento utilizado foi inteiramente casualizado com quatro repetições por tratamento. Após 120 dias nos tratamentos, foram mensurados o número de raízes, comprimento da maior raiz, número de folhas, comprimento da maior folha e massa fresca total. Depois as plântulas foram aclimatizadas em casa de vegetação e avaliada a taxa de sobrevivência após 75 dias. Os dados obtidos foram submetidos ao teste de Tukey a 5% de probabilidade e ajustadas curvas de regressão. A ausência de carboidrato reduziu o crescimento das plântulas entre todas as características avaliadas in vitro e ex vitro. As doses de glicose promoveram maior eficiência para o crescimento in vitro e sobrevivência acima de 90% após a aclimatização. Assim, a adição de glicose (30g L-1) ou sacarose (30g L-1) são recomendadas para a propagação massal de C. schilleriana.

In vitro development of Encyclea cordigera in different concentrations of honey / Desenvolvimento in vitro de Encyclea cordigera em diferentes concentrações de mel

ABSTRACT: The objective of this paper was to evaluate the effects of different honey concentrations in culture media, in comparison to sucrose medium, for the in vitro development of the epiphytic Encyclea cordigera orchid, in order to improve the process of propagation of the species. The in vitro germination was prepared on a reduced Murashige & Skoog (MS) medium. After 90 days, the seedlings were divided into different treatments, where they remained for another 90 days. Six treatments were set up (30g L-1 of sucrose; 15, 30, 45, and 60g L-1 of honey; and absence of any carbohydrates) in a completely randomized design. Plants were removed from the vials 270 days after the start of the experiment, and the number of roots, length of the largest leaf, length of the longest root, number of leaves, and fresh and dry masses were evaluated. Data concerning the number of leaves and roots were (x+1)1/2 transformed and subjected to an analysis of variance (ANOVA); the means were compared by a Tukey's test set at 5% probability. Medium containing 60g L-1 of honey proved to be superior to the sucrose medium traditionally used, favoring the in vitro growth and development of Encyclea cordigera. This medium can therefore be recommended for the propagation of this species, which is usually cultivated as an ornamental plant.

RESUMO: Este trabalho foi realizado com objetivo de avaliar a influência da concentração de mel no meio de cultura, comparando-o com a sacarose, para o desenvolvimento in vitro da orquídea epífita Encyclea cordigera, a fim de aperfeiçoar o processo de propagação dessa espécie. A semeadura in vitro procedeu-se em meio de cultura Murashige & Skoog (MS) reduzido e, após 90 dias, as plântulas foram distribuídas entre os tratamentos, em que permaneceram por mais 90 dias. Seis tratamentos (30g L-1 de sacarose, 15, 30, 45 e 60g L-1 de mel e ausência de carboidrato) foram utilizados, em delineamento inteiramente casualizado. Após 270 dias do início do experimento, as plantas foram retiradas dos frascos, sendo avaliado o número de raízes, comprimento da maior folha, comprimento da maior raiz, número de folhas, massa fresca e massa seca. Os dados de número de folhas e de raízes foram transformados (x+1)1/2 e submetidos à análise de variância (ANAVA); as médias foram comparadas pelo teste de Tukey a 5% de probabilidade. O meio de cultura suplementado com 60g L-1 de mel favoreceu o crescimento e desenvolvimento in vitro de Encyclea cordigera, sendo superior ao uso de sacarose, que é tradicionalmente usado, podendo ser recomendado para propagação dessa orquídea, que apresenta potencial ornamental.

Desenvolvimento inicial e crescimento in vitro de Cattleya violacea (Kunth) Rolfe em diferentes concentrações de sacarose / Initial development and in vitro growth of Cattleya violacea (Kunth) Rolfe in different sucrose concentrations

The aims of this study were to analyze the initial germination aspects and evaluate the effect of sucrose concentrations on in vitro growth of Cattleya violacea. Mature seeds from closed pods were sowed on MS (Murashige and Skoog) culture medium. The external morphology of seed and plantlets were documented by light and scanning electron microscopy. Plantlets with 90 days after sowing were subcultured on ½ MS (with half-strength macronutrients concentrations) culture medium with different sucrose concentrations (0, 10, 20, 30 and 40 g L-1), incubated under the same in vitro conditions during more 150 days followed by the evaluation of root number, root length, shoot length, fresh and dry weight. The biometric data were statistically analyzed and regression curves constructed. The seeds showed reticulate seed coat with a micropylar (opened) and chalazal (closed) end; the embryo results a chlorophyllated tuberiforme structure called protocorm, which may have rhizoids, leaflets and is considered plantlet when it has root. Absence of sucrose or the highest evaluated sucrose concentration was detrimental for plant growth. The concentration of 27 g L-1 provided the highest in vitro growth enabling great efficiency for mass propagation of this species of high ornamental potential.

O presente estudo teve por objetivo analisar os aspectos da germinação e avaliar o efeito de concentrações de sacarose no crescimento in vitro de Cattleya violacea. Sementes provenientes de cápsulas fechadas foram semeadas em meio de cultura Murashige e Skoog (MS) e a morfologia externa da semente à plântula foi fotodocumentada em estereomicroscópio e microscópio eletrônico de varredura. Plântulas com 90 dias após a semeadura foram repicadas em meio de cultura ½ MS (com metade da concentração de macronutrientes) com diferentes concentrações de sacarose (0, 10, 20, 30 e 40 g L-1), incubadas nas mesmas condições in vitro por mais 150 dias e em seguida as plântulas foram avaliadas quanto ao número de raízes, comprimento da maior raiz, número de folhas, comprimento da parte aérea, massa fresca e seca total. Os dados biométricos foram submetidos à análise estatística e a eles ajustadas curvas de regressão. As sementes apresentaram testa reticulada com uma extremidade micropilar (aberta) e calazal (fechada); o embrião originou uma estrutura tuberiforme clorofilada denominada protocormo que pode apresentar rizóides, folíolos e quando provido de raiz é considerado plântula. A ausência de açúcar ou a maior concentração avaliada de sacarose foram prejudiciais ao crescimento da planta. A concentração de 27 g L-1 proporcionou maior crescimento in vitro possibilitando maior eficiência para a propagação massal dessa espécie de elevado potencial ornamental.

Crescimento in vitro e aclimatização de Cattleya loddigesii Lindley (Orchidaceae) com carvão ativado sob dois espectros luminosos / In vitro growth and acclimatization of Cattleya loddigesii Lindley (Orchidaceae) with actived charcoal in two light spectra

O objetivo deste estudo foi avaliar a adição de concentrações de carvão ativado em meio de cultura ½ MS (com metade da concentração dos macronutrientes) sob dois espectros luminosos para a obtenção de plântulas in vitro de Cattleya loddigesii. Plântulas com aproximadamente 90 dias foram subcultivadas em oito tratamentos, nos quais foi testada a adição ao meio de cultura ½ MS com carvão ativado (0; 0,5; 1,0 e 2,0g L-1) e combinados sob espectro de luz branca e luz vermelha. Após 180 dias da germinação, foram mensurados dados biométricos (raiz e parte aérea), massa fresca e teores de pigmentos fotossintéticos. Em plântulas aclimatizadas em casa de vegetação, foram avaliadas a taxa de sobrevivência após 120 dias. As concentrações de clorofila total, clorofila a e carotenoides foram maiores nos tratamentos sob luz branca, enquanto a luz vermelha influenciou significativamente maior clorofila b, plântulas com menos raízes e de menor comprimento e elevada mortalidade ex vitro. A adição de 2,0g L-1 de carvão ativado ao meio de cultura e o uso de luz branca proporcionaram maior eficiência de desenvolvimento tanto para as culturas in vitro quanto para a sobrevivência ex vitro das plantas.

The aim of this study was to evaluate the effect of different concentrations of activated charcoal in ½ MS (half concentration of macronutrients) culture medium under two light spectra on the in vitro growth of Cattleya loddigesii seedlings. Plantlets with approximately 90 days were subcultured under eight treatments, consisting of different active charcoal concentrations (0; 0.5; 1.0 and 2.0g L-1) in ½ MS medium combined with white and red light spectra. After 180 days of germination, biometric data, fresh weight, and the level of photosynthetic pigments were evaluated. Plantlets acclimatized in a greenhouse were evaluated for survival after 120 days. Total chlorophyll, chlorophyll a, and carotenoid concentrations were higher in treatments under white light, while red light promoted greater chlorophyll b, plantlets with fewer and shorter roots, and high ex vitro mortality. The addition of 2.0g L-1 of active charcoal to the culture medium and the use of white light provided greater development efficiency both on in vitro culture and ex vitro plant survival.