Synthetic seed technology for encapsulation and regrowth of <i>in vitro</i>-derived <i>Acacia</i> hyrid shoot and axillary buds

Abstract

In this study, various concentrations of sodium alginate solutions and calcium chloride solutions were tested in order to optimize the size, shape and texture of alginate synthetic seeds or beads for Acacia hybrid bud-sprouting. The shoot buds and axillary buds from in vitro Acacia hybrids, as explants were encapsulated with 2 to 5% sodium alginate (w/v) in the Murashige and Skoog (MS) free of calcium salt solution solvent and exposed to 25 to 100 mM calcium chloride solution (CaCl₂.2H₂O). Rounded beads were observed by the encapsulation with alginate 3% and exposed to 75 to 100 mM CaCl₂.2H₂O combinations and; the encapsulation with alginate 4 to 5% and exposed to any CaCl₂.2H₂O combinations. The produced synthetic seeds were then tested on the plantlets regeneration ability. The germination rate was within 73.3 to 100% in the duration of 6 to 20 days. It showed that encapsulation at any alginate concentrations and exposed to any of the CaCl₂.2H₂O concentrations, gave high germination frequency. These plantlets could then be used as the source of explants for the subsequent experiments. The synthetic seeds have the possibility of being an alternative planting material meant for forestry sector in the future, especially for the highly demanded species.

Key word: Acacia hybrid, synthetic seeds, encapsulation, alternative planting material.