Effect of plant-derived smoke extract on in vitro plantlet regeneration from rapeseed (Brassica napus L. cv. Topas)microspore-derived embryos

The effect of aqueous smoke extract, derived from Tanacetum parthenium, on in vitro plantlet regeneration from rapeseed (Brassica napus L. cv. Topas) microspore-derived embryos (MDEs) was evaluated in this study. Inoculation of rapeseed MDEs with the smoke-extract dilutions (1:250, 1:500, 1:1000 and 1:2000) for various times (5, 10 and 15 min) significantly enhanced the percentage of regenerated plantlets from these embryos and also decreased the callogenesis percentage in these explants. The root length and shoot length of inoculated MDEs were significantly improved with all smoke-extract dilutions except for dilutions of 1:100 and 1:10. Application of smoke-extract solutions (1:1000, 1:500, 1:250 and 1:100) in B5 regeneration medium significantly enhanced the plantlet regeneration from rapeseed MDEs compared to control cultures. Furthermore, use of smokeextract solutions in combination with GA3 (0.1 and 0.15 mgl-1) significantly improved the root length and shoot length of rapeseed MDEs compared to separate use of smoke-extract solutions. Use of filter paper saturated with aqueous smoke extract (1:250) on top of the B5 regeneration medium was the best smoke treatment method improving the plantlet regeneration percentage, root length and shoot length of rapeseed MDEs compared to other treatment methods. The conversion frequency of rapeseed MDEs pretreated with smoke extract dilution of 1:500 was improved up to 50% compared with the control MDEs (26.67%), whereas the use of smoke extract (1:100) in B5 regeneration medium enhanced the conversion frequency of these MDEs up to 62% compared with the control cultures (26.67%). Keywords: Brassica napus L.; Plant-derived smoke; Plantlet regeneration; Microsporederived embryo.