An instructional system involving tropical hibiscus (Hibiscus rosa-sinensis) was developed for teaching hands-on grafting skills as part of a traditional comprehensive course in plant propagation and also as part of an online grafting course. The advantages of using tropical hibiscus include the following: the absence of phenological constraints associated with seasonal changes in temperate woody species; the comparative ease of grafting hibiscus, assuring positive reinforcement of the student's learning experience; and the ease of propagating and growing hibiscus in the greenhouse for use at any time of year. The three methods included in these laboratory exercises are top wedge grafting—selected for its ease and high rate of success—T-budding, and chip budding. In addition to development of hands-on skills, the exercises are designed to teach students three of the most important requirements for successful grafting of any species, regardless of method. These requirements include cambial alignment, application of pressure between stock and scion, and avoidance of desiccation. An online rating tutorial and lab report form was developed for students to self-evaluate their grafted plants.
Kenneth W. Mudge, Kelly Hennigan and Peter Podaras
Rebecca E. Scoville and Todd P. West
The objective of this study was to investigate the effects of multiple nutrient salt formulations and different plant growth regulator concentrations on initiation and proliferation of axillary shoot culture of tropical hibiscus (Hibiscus rosa-sinensis L.). Combinations of five thidiazuron (TDZ) concentrations (0, 10-6, 10-7, 10-8, or 10-9 M) in conjunction with two 6-benzylaminopurine (BA) concentrations (0, 10-5 M) and two indole-3-butryic acid (IBA) concentrations (0, 10-5 M) were compared to determine which plant growth regulator combination(s) would stimulate the proliferation of the most viable axillary shoots. Also, five nutrient salt formulations (MS, 1/2 MS; Macro MS, WPM, LP, or DKW) ranging from high to low salt formulations were studied to determine a suitable nutrient medium formulation for axillary shoot proliferation. Nodal explants that were 2 cm in length were used to initiate cultures and were maintained on the various medium treatments plus 30 g·L-1 sucrose and 7 g·L-1 agar at a pH of 5.8. Explants were incubated about 30 cm beneath cool-white fluorescent lamps that provide a photon flux of about 40 μM·m-2·s-1 for a 16-hour photoperiod at 25 ± 3 °C. Nodal explants were transferred every 3 weeks for a total culture period of 12 weeks. At each transfer date data were collected on node number, axillary shoot number and length. Initial results indicate that high nutrient salt formulations coupled with low TDZ concentrations performed better at axillary shoot initiation. Poor shoot elongation was observed and further research needs to be performed to address this issue.
Cecil T. Pounders and Hamidou Sakhanokho
Tropical hibiscus ( Hibiscus rosa-sinensis L.), also commonly known as the shoe flower or chinese hibiscus, is a widely planted tropical flowering shrub throughout the world. This cultivated species is generally a highly heterozygous polyploid of
Cecil T. Pounders and Hamidou F. Sakhanokho
Chinese hibiscus ( Hibiscus rosa-sinensis L.) or tropical hibiscus is extensively planted as a flowering pot plant worldwide and as a flowering shrub throughout tropical regions. Hibiscus rosa-sinensis has not been reported from the wild and is