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Unformatted text preview: CELL BIOLOGY AND MORPHOGENESIS Auxin pulse treatment holds the potential to enhance efficiency and practicability of somatic embryogenesis in potato Sanjeev Kumar Sharma Æ Glenn J. Bryan Æ Steve Millam Received: 31 October 2006 / Revised: 23 January 2007 / Accepted: 11 February 2007 / Published online: 28 February 2007 Ó Springer-Verlag 2007 Abstract The objective of the current study was to sim- plify existing somatic embryogenesis systems in potato ( Solanum tuberosum L.) cv. Desiree. The project targeted the agar-based induction phase of the potato somatic embryogenesis process as the key area for improvement. Experiments were established to ascertain the effect of a 2,4-D (2,4 dichlorophenoxyacetic acid) pulse, applied to the primary internodal section explant source and its sub- sequent effect on embryo induction. Parameters tested were the duration of the auxin pulse in a range from 0 to 300 min, and the concentrations of 2,4-D applied, in a range from 0 to 5,120 l M. The mean number of somatic embryos formed per explant was recorded after 4 and 8 weeks culture. Our findings indicated that the somatic embryogenesis in potato internodal segments could be evoked by an auxin (2,4-D) pulse treatment over a wide concentration and duration range. The results further sug- gested that a simple 20 l M 2,4-D pulse treatment could replace a lengthy 2 week induction phase in potato somatic embryogenesis and thus improve the system’s practicabil- ity for wider uptake. Keywords 2,4-D Á Potato ( Solanum tuberosum ) Á Internode Á Auxin pulse Á Somatic embryo Abbreviations 2,4-D 2,4 Dichlorophenoxyacetic acid cDNA Complementary DNA GA 3 Gibberellic acid IAA Indole acetic acid MS Murashige and Skoog NAA Naphthalene acetic acid Introduction Achievements in somatic embryogenesis, including its application to an increasingly wide range of species, have progressed with the continuous development of effective media formulations and methodology improvements. So- matic embryogenesis protocols generally employ the sequential use of two media compositions, an induction medium followed by a somatic embryo regeneration medium (Krikorian 2000 ). In many protocols, the induction medium contains auxin, usually 2,4-D, which has been widely accepted to be the principal controlling factor for embryogenesis. However, some workers have also reported the use of cytokinins in induction medium (Iantcheva et al. 1999 ). The regeneration medium usually lacks auxin, or contains very small concentrations, but is often supple- mented with other additives such as gibberellins and ab- scisic acid, which are recognised for their beneficial effects on embryo development and maturation (Brown et al....
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- Spring '09
- Plant embryogenesis, somatic embryogenesis