Multiple adventitious shoot formation in Spanish Red Cedar (Cedrela odorata L.) cultured in vitro using juvenile and mature tissues: an improved micropropagation protocol for a highly valuable tropical tree species

Abstract

Cedrela odorata L. is a valuable tropical tree widely appreciated for its wood. This species confronts serious problems due to both overexploitation of its natural populations and its susceptibility to the Meliaceae borer Hypsipyla grandella, which destroys the apical meristems and produces structural deformations. The rapid introduction of new varieties through clonal forestry has been demonstrated to be the most effective way to improve the production of perennial plantation species. In this work, we report both a protocol for the rejuvenation of elite mature trees of C. odorata and the optimization of an in vitro culture system to scale up micropropagation. Several media formulations and the use of temporary immersion culture in bioreactors were evaluated. The addition of 20% coconut water to TY17 medium increased the number of adventitious shoots from hypocotyl segments to an average number of 4.68 shoots per explant. To replace coconut water and to define the culture medium, several cytokinins were tested at various concentrations; however, none of them produced the effect of coconut water. Rejuvenation of elite mature individuals was investigated by ex vitro grafting of mature tree twigs onto 3-mo-old juvenile trees.Although the grafting had a positive effect on the micropropagation of mature material, the multiplication rate of 1.5 new shoots per explant did not compare to the organogenic capacity of younger materials. Shoot and root elongation as well as acclimatization to ex vitro conditions were carried out in a temporary immersion culture of juvenile material using BioMINT® bioreactors. A 3.5-fold increase in shoot elongation and a 4-fold increase in root elongation were achieved compared to material cultured on semisolid media. Furthermore, this culture system allowed for 98% effectiveness in the soil adaptation of the in vitrogrown plants. The scaled-up multiplication capacity over a period of 6 mo calculated for the system is above 16,000 plants per mother plant with young materials but is only 125 with mature materials.

Induction of somatic embryogenesis and plant regeneration in the tropical timber tree Spanish red cedar [Cedrela odorata L. (Meliaceae)]

“…We have previously reported on a protocol for C. odorata micropropagation in which hypocotyl segments were used as starting material and TY17 medium containing the plant growth regulator (PGR) dicamba was used as the induction culture medium (Gonzalez-Rodríguez and Peña-Ramírez 2007;Peña-Ramírez et al 2010). Using this protocol, we observed the induction of both adventitious shoot formation and the development of some proembryogenic calli.…”

Effects of immersion system and gibberellic acid on the growth and acclimatization of micropropagated pineapple

“…However, in the classes with longest shoots (5-6 cm, 6-7 cm, and higher than 7 cm), a higher regeneration was observed in TIS-TF. Similar results indicating the superiority of TIS for the production of shoots and plantlets with larger size were observed in peach palm (Steinmacher et al 2011), eucalyptus (McAlister et al 2005, Oliveira et al 2011), strawberry (Hanhineva et al 2005), Spanish red cedar (Peña-Ramíres et al 2010), lemon grass (Quiala et al 2006), sugarcane (Lorenzo et al 1998) and rubber tree (Etienne et al 1997). It was also observed that TIS-TF resulted in greater stability in the regeneration rate between different classes of shoot height.…”

PROPAGACION in vitro DE SEGMENTOS NODALES DE CEDRO (Cedrela odorata L.) OBTENIDOS A PARTIR DE SEMILLAS BOTANICAS

“…Estos datos contrastan con los resultados obtenidos en este estudio ya que en T2 se obtuvieron plantas de 4.82 cm y 2.87 nudos en 5 semanas de cultivo. La literatura muestra también que la adición de 20% de agua de coco en el medio TY17 incrementa el número de brotes adventicios a partir de segmentos de hipocotilo de cedro con un número promedio de 4.68 brotes por explante ( Peña-González-Rodríguez & Peña-Ramirez, 2007;Ramírez et al, 2010). Asimismo trabajos realizados con Cedrela fissilis muestran que la adición de BAP al medio de cultivo es indispensable para la brotación y multiplicación de brotes axilares (Da Costa-Nunes et al, 2001).…”