Title: 2,4,5-Trichlorophenoxyacetic acid promotes somatic embryogenesis in the rose cultivar Livin’ Easy’ (Rosa sp.).
Authors: Estabrooks, Tammy; Browne, Robin; Dong, Zhongmin.
Authors affiliation: Department of Biology, Saint Mary’s University, Halifax, NS, Can.
Published in: Plant Cell Reports (2007), 26(2), pages 153-160.
Abstract: “Somatic embryogenesis (SE) offers vast potential for the clonal propagation of high-value roses. However, some recalcitrant cultivars unresponsive to commonly employed SE-inducing agents and low induction rates currently hinder the commercialization of SE technol. in rose. Rose SE technol. requires improvement before it can be implemented as a prodn. system on a com. scale. In the present work, we assessed 2,4,5-trichlorophenoxyacetic acid (2,4,5-T), a synthetic auxin not previously tested in rose, for its effectiveness to induce SE in the rose cultivar Livin’ Easy’ (Rosa sp.). We ran a parallel comparison to the commonly used 2,4-dichlorophenoxyacetic acid (2,4-D). We tested each auxin with two different basal media: Murashige and Skoog (MS) basal medium and woody plant medium (WPM). MS medium resulted in somatic embryo prodn., whereas WPM did not. 2,4,5-T induced SE over a greater concn. range than 2,4-D’s and resulted in significantly greater embryo yields. 2,4,5-T at a concn. of 10 or 25 mM was better for embrygenic tissue initiation than 2,4,5-T at 5 mM. Further embryo development occurred when the tissue was transferred to plant growth regulator (PGR) free medium or media with 40% the original auxin concn. However, the PGR-free medium resulted in a high percentage of abnormal embryos (32.31%) compared to the media contg. auxins. Upon transfer to germination medium, somatic embryos successfully converted into plantlets at rates ranging from 33.3 to 95.2%, depending on treatment. Survival rates 3 mo ex vitro averaged 14.0 and 55.6% for 2,4-D- and 2,4,5-T-derived plantlets, resp. Recurrent SE was obsd. in 60.2% of the plantlets growing on germination medium. This study is the first report of SE in the com. valuable rose cultivar Livin’ Easy’ (Rosa sp.) and a suitable methodol. was developed for SE of this rose cultivar.”