Efficiencies in Alginate Encapsulation of Vegetative Explants

The goal of this study was to improve a non-mechanized bulk encapsulation technique to standardize encapsulation procedures and reduce the labor time compared to encapsulating individual nodes.  Four mm-long nodal segments from Stage II cultures of Hibiscus moscheutos L. ‘Lord Baltimore’ were encapsulated as groups of 5 segments in matrix masses gelled with 2.5 - 3.25% sodium alginate that were solidified with 60 - 90mM calcium chloride in various experiments.  Encapsulated masses were placed in sterile Petri dishes, sealed with parafilm, and placed in darkness at 5°C for four weeks.  They were then removed from refrigeration and placed on fresh Stage II medium and incubated at 25°C under cool white fluorescent lamps for four weeks when data were taken.  There was a significant interaction between the alginate viscosity and the calcium chloride concentration for subsequent shoot length.  The most axillary shoots grew when the masses were encapsulated in 3% alginate and 60mM CaCl₂. The longest shoots grew from nodal segments encapsulated with 2.75% alginate that was solidified with 60mM CaCl₂.  The most roots grew from masses of nodal segments encapsulated in 2.5% alginate solidified with 60mM CaCl₂.