Reproduction of Polygala myrtifolia l. plants by tissue culture technique

This study was carried out at Dept. of Ornamental Hort. Fac. Agric., Cairo Univ., and the applied part was carried out at the Tissue Culture Laboratory, Horticulture Research Institute, Agriculture Research Center, during 2007-2009 seasons to develop an efficient protocol of Polygala myrtifolia L. propagation by tissue culture technique. Different disinfection agents (sodium hypochlorite and ethanol), explant types (apical, middle and basal), cultural seasons (summer, autumn, spring and winter), plant growth ,regulators (BA, kin, NAA, IAA and IBA), MS medium strengths (1/4, 1/2 and 3/4), commercial fertilizer (Nofatrein) concentrations as well as supporting agents (agar, gelrite and filter paper bridge) and acclimatization medium substrates (peatmoss, vermiculite and sand) were employed in these experiments. Important results could be summarized as follows: To produce aseptic cultures, soaking apical explants in 20% Clorox (sodium hypochlorite) solution either for 10 or 15 minutes without presoaking in 70% ethyl alcohol was the best in producing the lowest contamination percentage, the highest survival% and the lowest mortality%. During establishment stage, apical explants cultured during spring season recorded the highest survival%, while middle explants were more successful in other parameters, i.e. number of shoots/explant, shoot length and number of leaves/shoot, when they were cultured during autumn season. Multiplication experiments showed that the highest survival% was obtained either by BA at I mg/I or kin at 2 mg/I without NAA addition or by BA at I mg/I with NAA at 0.5 mg/I. BA at I mg/I without NAA addition presented the highest number of shoots/explant. In the same regard, Nofatrein at I mg/I with '/% MS medium strength gave the highest number of shoots/explant and leaves/shoot. This was accompanied by an increase in survival%. Results of rooting experiments demonstrated that IBA at I mg/I when applied as a presoaking solution presented the highest rooting% and number of roots/plantlet, while IBA at 1.5 mg/I added to the medium presented the longest roots. On the other hand, IBA free medium solidified with agar+gelrite produced the highest survival% and rooting%. Number of roots reached the maximum value by using IBA at I mg/I with agar. IBA at I mg/I with filter paper bridge presented the longest roots, the highest carotenoids, the highest phenols and the highest total soluble sugars content. Peatmoss+vermiculite (1:1, v/v) was superior in increasing most characteristics as survival%, plant height, number of leaves/plantlet, leaf area, number of roots, plantlet fresh weight, total chlorophylls, total indoles and total soluble sugar during acclimatization stage..