Improving plantlet yield in Pinus pinaster somatic embryogenesis

Abstract

Somatic embryogenesis is expected to play a significant role in the future forest tree improvement programmes. The main bottleneck of this technique is still the progression from immature embryogenic cultures to mature cotyledonary embryos able to develop properly into well-growing plants. In this work, we present an improved protocol focused on increasing the maturation and conversion rate of Pinus pinaster Ait. embryogenic cultures. Results showed that the optimisation of the nutrient composition in the maturation medium increased the number of mature embryos by 25% (187.8 embryos per gram of fresh mass in average compared to 144.5 embryos in regular medium). It was also shown that 12-month cryostorage did not reduce viability or embryogenic ability of maritime pine cultures. A further increase in the yield of the protocol could be obtained by using benzyladenine in the conversion medium, promoting the bud-break of axillary buds that yielded 5.7 shoots in average per somatic embryo. Rooting of axillary shoots reached 84.3%. This methodology offers an alternative to overcome some problems associated with low somatic embryo production since the plantlet yield could be increased fivefolds.

Keywords:

• Conifer
• cryopreservation
• maturation
• organogenesis
• somatic embryogenesis

Acknowledgements

The authors thank Dr. Rubén Alvarez for proofreading the manuscript and the helpful comments. This work was supported by “Ministerio de Educación y Ciencia de España” (AGL2009-12139-C02-01); “Plan de Ciencia, Tecnología e Innovación del Principado de Asturias” (IB08-054 and FC10-COF10-07); predoctoral grant from the “Ministerio de Educación y Ciencia de España” (FPU AP2005-0140) to J.M. Alvarez and from “Plan de Ciencia, Tecnología e Innovación del Principado de Asturias” (BP10-098) to N. Bueno.

Supplemental Data

Supplemental data for this article can be accessed at http://dx.doi.org/10.1080/02827581.2013.821516