In vitro propagation of Acacia hybrid through alginate-encapsulated shoots and axillary buds
Seed collected from Acacia hybrid trees yields highly variable and poorly performing offspring and are not commonly used in regeneration. The present study described the incapsulation of Acacia hybrid shoots and axillary buds in the calcium alginate gel. The aim of the study was to evaluate the germination of the buds in vitro on the medium with different concentrations of plant growth regulator and; the performance of the germination under light and darkness. For encapsulation purposes, 3% sodium alginate (w/v) in the Murashige and Skoog (MS) free of calcium salt solution solvent were tested. While for complexation, 100 mM calcium chloride solutions (CaCl2.2H2O) were prepared in liquid MS medium. The encapsulated explants or the beads were cultured into the following media: Modified basal MS supplemented with 6-benzylaminopurine (BAP) ranging from 0 to 2.5 mg/L BAP. High germination rate (100%) was observed within five to eight days in all medium tested. Analysis of variance showed no significant difference in the ability of the synthetic seeds to germinate. This showed that the regeneration of shoots is possible by using basal MS only. It was observed that synthetic seeds needed sucrose more than plant growth regulator for its germination. They were also showing good regeneration and development under light condition.
Key words: Acacia hybrid, synthetic seeds, encapsulation, germination, regeneration.