Poster: Late and Moved Abstracts

Abs # 1407: The effect of 2,4,5-trichlorophenoxyacetic acid on rose somatic embryogenesis

Presenter:	Estabrooks, Tammy L., T_ESTABROOKS@smu.ca
Authors	Estabrooks, Tammy L. (A)   Browne, Robin  (B)   Dong, Zhongmin  (A)
Affiliations:	(A): Saint Mary's University (B): PlantSelect Biotechnology Systems Ltd.

Somatic embryogenesis (SE) technology requires improvement before it can be implemented on an industrial scale as a clonal propagation system for roses. Due to genotype-specificity, there is not a universal protocol successful in inducing SE in all cultivars of rose. This study investigated the effects of the commonly employed auxin 2,4-dichlorophenoxyacetic acid (2,4-D) with one not previously reported in rose, 2,4,5-trichlorophenoxyacetic acid (2,4,5-T).These two compounds were tested at various concentrations in two different basal media (MS and WPM) using both leaflet and petiolte explants of the rose cultivar 'Livin' Easy'. Frequency of callus formation, embryogenic tissue initiation, somatic embryo formation, germination and survival rates after transfer to soil were determined. 2,4,5-T in MS medium promoted the highest percentage of SE induction for both leaflet and petiole explants. 2,4-D was not successful in producing somatic embryos, although callus and embryogenic tissue were successfully induced. 2,4,5-T had a wider working concentration range than 2,4-D in inducing embryogenic tissue and was successful in producing embryos when embryogenic tissue was transferred to either medium containing lower concentrations (40% of original) of 2,4,5-T or auxin-free medium. These results may prove useful for the induction of SE in rose cultivars unresponsive to 2,4-D. The genetic mechanisms underlying the different effects of 2,4-D and 2,4,5-T on embryo development are currently under investigation.