(281) Effects of Colchicine and Oryzalin on Callus and Adventitious Shoot Formation of Euphorbia pulcherrima `Winter Rose'™

Abstract

<jats:p>Poinsettia, <jats:italic>Euphorbia pulcherrima</jats:italic>, is an important holiday symbol and is the number one flowering potted plant in the United States. The technique of chromosome doubling has been utilized to increase size of flowers, stems, and leaves of many species, and has been used in poinsettia breeding to obtain new cultivars. Application of colchicine or oryzalin to in vitro tissues may be used to enlarge the inflorescences and brackets and reduce the height of `Winter Rose'™ poinsettias, reduce the likelihood of chimeric tetraploids, and provide a rapid means for producing many tetraploid plants. The purpose of this research was to evaluate the effect of colchicine and oryzalin on callus and adventitious shoot formation of `Winter Rose'™ poinsettia with in vitro grown leaf tissues and its potential for tetraploid induction. In vitro grown leaf midvein sections were placed on various media supplemented with either colchicine or oryzalin at various concentrations for 1–4 days. Colchicine was least damaging to leaf tissues at concentrations of 0.25 or 250.4 μ<jats:sc>m</jats:sc>. A large amount of callus, as well as adventitious shoots, were produced. Regenerated shoots were found to be diploid, determined by flow cytometry. On media with oryzalin (28.9–144 μ<jats:sc>m</jats:sc>), leaf tissues produced callus, but not adventitious shoots. Calluses produced on oryzalin-containing media were tested using the flow cytometer and were found to be diploid.</jats:p>

Induced Polyploidy in Diploid Ornamental Ginger (Hedychium muluense R. M. Smith) Using Colchicine and Oryzalin

“…L.), poinsettias (Euphorbia pulcherrima Willd. ex Klotzsch), and Watsonia lepida N. E. Brown (Ascough et al, 2008;Pickens et al, 2006;Sloan and Camper, 1981). Callus production slightly increased (compared with the control media) and remained generally constant in culture media containing 30 or 60 mM oryzalin, regardless of exposure time, but steadily declined over time for medium containing 120 mM oryzalin ( Table 2).…”

“…Induced polyploidy has been achieved in several plant species using the antimitotic chemicals colchicine and oryzalin (Dhooghe et al, 2009;Pickens et al, 2006;Rey et al, 2002). Colchicine binds poorly to plant tubulins but has a high affinity for animal microtubulins and thus is toxic to humans (Morejohn et al, 1987).…”