In vitro culture of Hibiscus rosa-sinensis L.: Influence of iron, calcium and BAP on establishment and multiplication

Some factors influencing in vitro cultures of potted Hibiscus rosa-sinensis L. using nodal cuttings were investigated. A protocol using a modified MS medium helped to overcome chlorosis, shoot tip necrosis (STN) and leaf drop. These disorders have been caused by mineral imbalance associated with calcium and iron deficiency. STN and leaf drop were overcome by increasing calcium level from 3 mM (MS standard concentration) to 9 mM, and this increase, in addition, enhanced shoot dry weight and shoot extension. The chlorophyll content and leaf area increased by increasing the iron concentration 3-fold from 98 μM to 295 μM. Furthermore, substituting Fe-EDTA with Fe-EDDHA resulted in an increase in chlorophyll content, leaf area and shoot extension. The most suitable multiplication medium for H. rosa-sinensis L. was demonstrated to be a modified MS medium containing 2.2 μM BAP and increased concentrations of calcium at 9 mM and iron at 295 μM provided as Fe-EDDHA. The shoots were rooted in half-strength modified MS medium containing 2.7 μM NAA. Acclimatization was successful with all shoots with or without roots.