ABSTRACT
Aims: Temporary Immersion Bioreactor (TIB) system is an advanced technology for commercial mass production of potato microtubers. Despite of several advantages, this system possess a great risk of culture loss at any stage of micropropagation due to microbial contamination. The aims of this study were to identify microbial contaminants isolated during potato shoot growth in the TIB system, evaluate the efficacy of antimicrobial agents to prevent them, to investigate the effect of those agents in vitro on growth and morphology of potato plantlets. Methodology and results: Six bacteria namely Pseudomonas, Staphylococcus, Klebsiella, Corynebacterium, Proteus, Bacillus and five fungi Aspergillus, Penicillium, Mucor, Fusarium and Rhizopus were isolated from the TIB system. We examined the effect of three antibacterial (Gentamycin, Vancomycin and Tetracycline) and four antifungal agents (Mencozeb, Propiconazole, Bavistin and Copper oxychloride) on the contaminants and on potato shoot growth. Results show that Gentamycin (50 mg/L) and Propiconazole (0.15%) were most effective against the isolated bacteria (35 mm inhibition zone) and fungi (100%) respectively, whereas Gentamycin in combination with Bavistin showed better performance on potato shoot and root development. Conclusion, significance and impact of study: Present study will provide useful guidelines to reduce or eliminate the risk of contamination during micropropagation.
ABSTRACT
La micropropagación es una alternativa para la producción comercial de plantas de zábila (Aloe barbadensis Mill.) limitada por los altos costos de producción. Con el objetivo de prescindir de los agentes gelificantes, reduciendo costos, se comparó el medio de cultivo líquido con el medio de cultivo gelificado en las diferentes etapas de micropropagación de la zábila. En la etapa de establecimiento se observó mayor porcentaje de explantes contaminados en el medio de cultivo líquido estático (25.55 %) que en el medio gelificado (11.11 %); y aunque el resto de los explantes se establecieron independientemente de la condición del medio de cultivo, en el medio líquido alcanzaron mayor altura (3.81 cm) que en el medio gelificado (3.03 cm). En la etapa de multiplicación, la altura de los explantes (entre 4.43 y 6.01 cm) fue superior en los recipientes de inmersión temporal automatizado (RITA®) en comparación con el medio gelificado (entre 3.24 y 3.42 cm); sin diferencias significativas entre el número de brotes/explante. Todos los brotes enraizaron a los 30 días independientemente del medio de cultivo empleado (líquido estático y gelificado), sin observar variaciones en la altura del brote y, número y longitud de las raíces. El empleo de los medios de cultivo líquidos y la implementación de los sistemas de inmersión temporal tipo RITA® permiten reducir los costos de producción al prescindir de los agentes gelificantes, lo que representa un avance para la micropropagación comercial de zábila.
Micropropagation is considered a successful alternative for aloe (Aloe barbadensis Mill.) plant production. However, it has limited use due to the high production cost. Liquid media were compared to agar-gelled medium during all micropropagation stages of aloe to reduce the cost for gelling agent used. In the establishment stage, there was a higher percentage of contaminated explants in static liquid medium (25.55%) than those cultured in agar-gelled medium (11.11%), although all the explants were established independently of the culture medium used, higher height (3.81 cm) was observed in liquid medium than those growing in agar-gelled medium (3.03 cm). In the multiplication stage, explant height was higher in the recipients used for automated temporary immersion system (RITA®) (4.43 - 6.01 cm) than those cultured in agar-gelled medium (3.24 - 3.42 cm), there was no significant difference for number of shoots/explant. All shoots had roots at 30 days independently of used culture media (static liquid or agar-gelled media). Shoot height, number and root length had similar values in both culture media. The implementation of liquid media and automated temporary Immersion system RITA® may allow to reduce production costs of gelling agent used, it represents an approach for the commercial micropropagation of aloe.
ABSTRACT
The aim of the present research was to verify the in vitro growth of orchids in different systems of micropropagation, being cultivated in a bioreactor, with natural ventilation and conventional systems. Cattleya walkeriana plants were obtained from the germination of seeds in culture medium. After 8 months, seedlings with 1 cm of length were placed in a culture vessel according to the treatments, which counted with two micropropagation systems (conventional and natural ventilation) in three media of culture (liquid, solid with 5 or 6g L-1 of agar). Two additional treatments in bioreactor of temporary and continuous immersion were performed. The design was entirely randomized (ERD), consisting of a 2x3 factorial with two additional treatments, totaling 8 treatments with three repetitions. The temporary immersion bioreactor promoted a bigger growth of the aerial part and of the root system, bigger accumulation of dry mass and better control of water loss by the plants. The temporary immersion bioreactor is the best micropropagation system for the C. walkeriana growth in vitro.
O objetivo do presente trabalho foi verificar o crescimento in vitro de orquídeas em diferentes sistemas de micropropagação, sendo cultivado em biorreator, sistema de ventilação natural e convencional. Plantas de Cattleya walkeriana foram obtidas a partir da germinação de sementes em meio de cultura. Após o a germinação, as plantas foram uniformizadas com aproximadamente 1,0cm de comprimento e inoculadas nos diferentes tratamentos. Os tratamentos contaram dois sistema de micropropagação (convencional e ventilação natural) e três meios de cultura (líquido, sólido com 5 e 6g L-1 de ágar). Foram realizados dois tratamentos adicionais em biorreator de imersão temporária e contínua. O delineamento foi o inteiramente casualizado, consistindo de um fatorial 2x3 com dois tratamentos adicionais, totalizando oito tratamentos com três repetições. O biorreator de imersão temporária promoveu o maior crescimento da parte aérea e do sistema radicular, maior acúmulo de massa seca e melhor controle da perda de água das plantas. O biorreator de imersão temporária é o melhor sistema de micropropagação para o crescimento in vitro de C. walkeriana.
ABSTRACT
Deschampsia antarctica (DA), the only species in the Gramineae family endemic to the Antarctic territory, is characterized by a combination of high levels of free endogenous phenylpropanoid compounds under normal in situ and in vitro growth conditions. In this article, we describe the design and use of a specific temporary immersion photobioreactor to produce both increased DA biomass and secondary metabolite accumulation by UV-B elicitation during cultivation. Three min-long immersions in an induction medium applied every 4 hrs at 14ºC +/- 1 and 20/4 hrs light/darkness photoperiod increased DA biomass production over previous in vitro reports. Biomass duplication was obtained at day 10.7 of culturing, and maximum total phenolics and antioxidant activity were observed after 14 day of culturing. The addition of UV-B radiation pulses for 0.5 hrs at 6 hrs intervals increased total phenolics and antioxidant activity more than 3- and 1.5- fold, respectively, compared to controls with no UV-B. Significant accumulation of scopoletin, chlorogenic acid, gallic acid and rutin was found in these plantlets. This is the first bioreactor designed to optimize biomass and phenylpropanoid production in DA.
Subject(s)
Phenols/metabolism , Poaceae/radiation effects , Poaceae/metabolism , Bioreactors , Ultraviolet RaysABSTRACT
Protocormos in vitro de Phalaenopsis de tres meses de edad se transfirieron a contenedores RITA® con el fin depropagarlos masivamente. Los factores evaluados fueron la concentración de sacarosa en el medio y la frecuencia de inmersión. Se dispusieron cinco pares de contenedores RITA® con medio de cultivo líquido a concentraciones de sacarosa de 0, 15, 30, 45 y 60 g/L. El medio utilizado fue el MS a la mitad de la concentración de las sales, suplementado con vitaminas y tidiazuron (5 mg/L). El experimento se realizó en dos etapas, cada una con duración de dos meses. La primera etapa con una frecuencia de inmersión de cuatro horas y la segunda con una frecuencia de inmersión de ocho horas, ambas con un tiempo de inmersión de un minuto. Los resultados mostraron que la mejor respuesta proliferativa, con 8,2 protocormos adventicios por protocormo por mes, se obtuvo en el medio con 15 g/L de sacarosa y un tiempo de inmersión de un minutocada cuatro horas.
In order to massively propagate Phalaenopsis orchids, three months old in vitro protocorms were transferred to RITA® vessels. The evaluation factors were the sucrose concentration in the culture medium and the frequency immersion. There was a set of five pairs of RITA® vessels with liquid culture medium containing sucrose at 0, 15, 30, 45, 60 g/L. A half-strength MS medium plus vitamins, supplemented with vitamins and thidiazuron (5 mg/L) was used. The experiment had two stages, each lasting two months. Each stage had a one minute immersion. The first stage had a four hour immersion frequency and the second one had an eight hour immersion frequency. Results showed that the best proliferating response was reached in a 15 g/L of sucrose medium with one minute of immersion time every four hours, resulting in 8,2 adventitious protocorms per protocorm per month.