RESUMO
El mantenimiento en campo de los Bancos de Germoplasma resulta muy costoso, además de los riesgos a que se exponen. El cultivo de tejidos constituye una solución a estos problemas siendo conveniente utilizar una combinación de técnicas de almacenamiento en los cultivos de propagación vegetativa para no depender de una sola. El cultivo in vitro ofrece nuevas alternativas para el mejoramiento de la productividad y la producción de material de siembra sano en malanga (Xanthosoma spp.). La presente investigación se desarrolló en el Laboratorio de Cultivo de Tejidos del Instituto de Investigaciones de Viandas Tropicales (INIVIT), Cuba, con el objetivo de estudiar las condiciones para la conservación en crecimiento mínimo in vitro de germoplasma de esta especie. Como material vegetal se utilizó el clon de Malanga Xanthosoma "INIVIT MX-2008". El establecimiento del material vegetal y su posterior multiplicación fueron realizadas según la metodología recomendada por García et al. (1999). Para la conservación en medio de cultivo de crecimiento mínimo se utilizó el medio basal MS y se estudiaron 15 tratamientos que combinaron concentraciones de Manitol (regulador osmótico) (1,5; 3 y 4%) y Nitrato de plata (inhibidor de la acción etileno) (0, 2, 4, 8, 10 mg.L-1). Se concluye que es posible conservar in vitro los recursos genéticos de malanga Xanthosoma durante más de 10 meses, en un medio de cultivo compuesto por sales y vitaminas MS suplementado con 4% de manitol y 4 mg.L-1 de Nitrato de plata. Las plantas propagadas a partir de este medio de cultivo se recuperaron exitosamente. La mayor concentración de manitol en el medio de cultivo pudo haber influido en la mejor recuperación del material conservado.
Maintenance field genebanks are costly, in addition to the risks they face; to that effect on tissue culture is a solution to these problems. In vegetative propagated crops is desirable to use a combination of storage technology rather than relying on just one. in vitro culture provides an alternative for improving productivity and production of healthy planting material of taro (Xanthosoma spp.). This research was conducted in the Tissue Culture Laboratory of the Research Institute of Tropical Crops. Our objective was study the conditions for minimal growth conservation in vitro germplasm in this species. As plant material was used clone of Taro Xanthosoma 'INIVIT MX-2008'. The establishment of the plant material and its subsequent multiplication were carried out according to the methodology recommended by García et al. (1999). For the maintenance in culture of minimal growth basal medium MS was used and studied 15 treatments with combined concentrations of mannitol (osmotic regulator) (1.5, 3 and 4%) and silver nitrate (Ethylene inhibitor) (0, 2, 4, 8, 10 mg.L-1). It concludes that it is possible to conserve taro Xanthosoma genetic resources in vitro, for over 10 months in a culture medium composed of MS salts and vitamins and supplemented with 4% mannitol and 4 mg.L-1 of silver nitrate. Plants propagated from this culture medium were recovered successfully. The presence of higher concentrations of mannitol, may have influenced that increases survival of preserved material. O3.
Assuntos
Manitol , Nitrato de Prata , Xanthosoma , CrescimentoRESUMO
A conservação in vitro é uma estratégia de conservação ex situ que garante a manutenção da integridade genética e biológica das espécies. O objetivo deste estudo foi avaliar o efeito de agentes osmóticos e temperatura na conservação in vitro de Syngonanthus mucugensis Giul. subsp. mucugensis. Os brotos foram inoculados em meio de cultura MS ½ contendo 7g L-1 de ágar e suplementado com 60g L-1 de sacarose, e com as concentrações de sacarose 15, 30 e 45g L-1 combinados com 0 e 15g L-1 de sorbitol ou manitol. As culturas foram mantidas em duas temperaturas (18 e 25°C). A porcentagem de sobrevivência das plantas foi avaliada mensalmente e ao final de 180 dias foram analisados o comprimento da parte aérea e da raiz, a porcentagem de folhas verdes, a porcentagem de explantes com brotos, o número de brotos por explante e o comprimento dos brotos. Os agentes osmóticos promoveram um decréscimo no crescimento das plantas, no entanto reduziram a sua viabilidade. Os resultados observados nos experimentos mantidos a 18°C foram significativamente superiores aos encontrados a 25°, para todas as variáveis analisadas. A conservação de S. mucugensis subsp. mucugensis pode ser feita à 18°C em meio de cultura MS ½ contendo 15g L-1 de sacarose, por até 180 dias, sem subcultivo.
The in vitro conservation is an ex situ conservation strategy that ensures the maintenance of genetic and biological integrity of species. The present study evaluated the effects of, osmotic agents and different temperature regimes on the in vitro conservation of Syngonanthus mucugensis Giul. subsp. mucugensis. The shoots were inoculated into half salt strength Murashige and Skoog culture medium (MS ½) containing 7g L-1 of agar. The culture medium was supplemented with 60gL-1 sucrose and with the sucrose concentrations 15, 30 and 45g L-1 combined with 0 and 15g L-1 of sorbytol or mannitol. Two different temperatures were used in these experiments (18 and 25°C). The percentage of plant survival was evaluated monthly and at 180 days were analyzed length of shoot and root, the percentage of green leaves, the percentage of explants with shoots and number of shoots per explants and shoot length. The addition of osmotic agents resulted in decreased growth of the plants and therefore reduced their viability. The averages observed in the experiments undertaken at 18°C were significantly superior to those observed at 25°C for all of the variables analyzed. S. mucugensis subsp. mucugensis can be cultured at 18°C in MS½ culture medium containing 15g L-1 of sucrose, for up to 180 days, without subculturing.