The Effect of Slow-grown in Vitro Storage Under Different Light Spectra on Banana Plantlets Cv. Prata Catarina (AAB).

Maintaining updated in vitro plant subcultures is essential for commercial micropropagation and tissue culture research. In unusual situations, the subcultures can be delay and the slow-growth in vitro storage technic could be applied to reduce the loss of plant material. The present study aimed to evaluate the slow-growth in vitro storage of banana plantlets (‘Prata Catarina’; group AAB) under different light spectra. Shoot cultures in MS medium without plant growth regulators were maintained under blue (B), red (R), red plus blue (R2B), and white (CW) light spectra (25°C ± 2°C; 50 µmol m -2 s -1 ) for up to 140 days. The plantlets maintained under the R, CW, and R2B spectra did not survive after 140 days of in vitro slow-growth storage. The plantlets maintained under the B spectrum survived after 140 days of in vitro slow-growth storage and showed little browning.

In vitro rooting of hybrid hazelnuts (Corylus avellana × Corylus americana) in a temporary immersion system

Commercial micropropagation of hybrid hazelnuts (Corylus avellana L. × C. americana Marshall) has been limited, owing to their poor rooting ability in vitro as well as ex vitro, leading to high mortality of plantlets transplanted in the greenhouse. The objective of this study was to develop an efficient and cost-effective protocol for rooting and plantlet acclimation of in vitro grown hazelnut shoots. Efficient in vitro rooting was accomplished in a rocker-based temporary immersion bioreactor system. The use of a temporary immersion system (TIS) in combination with the inert substrate Oasis® In Vitro Express (IVE) significantly improved the in vitro rooting efficiency (100%) compared with semi-solid medium (27%) after four weeks of culture. A higher density (36 explants/vessel) of shoot explants in the TIS was found to support a significantly greater shoot height, chlorophyll content, and longest root length, compared with the lowest density treatment (12 explants/vessel). Efficiency of rooting and the number of roots formed were similar for both the high and low density of explants in the culture vessels, and the resulting plantlets exhibited > 80% survival in the greenhouse. These results demonstrate the usefulness of rocker-based TIS for commercial micropropagation of hazelnuts and, potentially, other tree species.

PROTOCOLOS DE DESINFECCIÓN DE EXPLANTES DURANTE LA MICROPROPAGACIÓN DE Cedrela odorata L.

EXPLANTATION DISINFECTION PROTOCOLS DURING THE MICROPROPAGATION OF Cedrela odorata L.RESUMENLa contaminación microbiana es uno de los problemas más graves en la micropropagación de las especies vegetales, tanto en la investigación como en la micropropagación comercial. Tal contaminación puede ser producida por microorganismos endofíticos o microorganismos introducidos durante la manipulación de laboratorio. El presente trabajo se realizó con el objetivo de evaluar tres protocolos de desinfección de explantes para la micropropagación de Cedrela odorata L., en el laboratorio de biotecnología vegetal de la Universidad Estatal del Sur de Manabí. La metodología aplicada se basó en el montaje de un diseño experimental en bloque completamente al azar. Se evaluaron tres tratamientos para la desinfección de explantes, obteniéndose con éxito el 95.64% de explantes establecidos en el segundo tratamiento, en el que se utilizó un protocolo de desinfección basado en Etanol al 50% (C2H6O), Hipoclorito de Sodio (NaClO) en el 25% de su concentración. Tiempo de inmersión de 60 segundos. Existen diferencias estadísticas altamente significativas en los protocolos utilizados para la desinfección de explantes de Cedrela odorata. Sólo un tratamiento, T2, fue el que presentó la mayor eficiencia durante el experimento.PALABRAS CLAVE: Propagación, especies amenazadas, madera tropical.ABSTRACTMicrobial contamination is one of the most serious problems in micropropagation of plant species, both in research and in commercial micropropagation. Such contamination may be produced by endophytic microorganisms or microorganisms introduced during laboratory manipulation. The present work was carried out with the objective of to evaluate a disinfection protocol of explants for the micropropagation of Cedrela odorata L., in the plant biotechnology laboratory of the Southern State University of Manabí. The applied methodology was based on the assembly of an experimental design in block completely at random. Three treatments were evaluated for the disinfection of explants, successfully obtaining 95.64% of explants established in the second treatment, in which a disinfection protocol based on 50% Ethanol (C2H6O), Sodium Hypochlorite (NaClO) in 25% of its concentration, with a time of immersion of 60 seconds. There are statistically significant differences in the protocols used for the disinfection of Cedrela odorata explants. Only one treatment, T2, was the one that presented the highest efficiency during the experiment.KEYWORDS: propagation, threatened species, tropical timber.

Effects of Different Culture Media on Growth and Proliferation of Dendrobium ‘Earsakul’ Protocorm-like Bodies

The effects of culture media on growth and proliferation of ‘Earsakul’ dendrobium (Dendrobium) protocorm-like bodies (PLBs) were evaluated in a two-step culture. After culturing on each of the four first step media for 4 months and on each of the four second step media for 4 months, the greatest total PLB fresh weight, increase in number of PLBs and growth rates were obtained when using Vacin and Went medium 1 (VW1) in both culture steps compared with those in 15 other medium combinations. Starting from 0.5 g of PLBs, culturing on VW1 for 8 months achieved a total of 415.25 g of PLBs, a multiplication rate of 830-fold. The supplementation of tomato (Solanum lycopersicum) and substitution of ‘Hom Thong’ banana [Musa acuminata (AAA group)] with ‘Khai’ banana [M. acuminata (AA group)] in this new medium promoted growth and proliferation of dendrobium PLBs 2.4-fold over the control medium, suggesting its usefulness in commercial micropropagation.

Medios de cultivo líquidos: un avance para la micropropagación comercial de zábila (Aloe barbadensis Mill.)

<p><strong>Título en imgles: </strong><strong><strong>Liquid medium culture: an approach for the commercial micropropagation of aloe (<em>Aloe barbadensis</em> Mill.) <strong></strong></strong></strong></p><p><strong><strong><strong>Título corto: Un avance para la micropropagación comercial </strong><strong>de zábila</strong></strong></strong></p><p><strong>Resumen:</strong><strong> </strong>La micropropagación es una alternativa para la producción comercial de plantas de zábila (<em>Aloe barbadensis</em> 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. </p><p><strong>Palabras clave:</strong> Cultivo de tejidos, agentes gelificantes, RITA^®, sistemas de inmersión temporal.<strong></strong></p><p><strong>Abstract</strong>: Micropropagation is considered a successful alternative for aloe (<em>Aloe barbadensis</em> 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.<strong></strong></p><p><strong>Keys words:</strong> Tissue culture, gelling agents, RITA^®, temporary immersion system.<strong></strong></p><p><strong>Recibido: </strong> junio 15 de 2014<strong> Aprobado: </strong>abril 13 de 2015</p>