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

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

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

Preliminary study of in vitro propagation of a selected high yielding clone of kacip fatimah (Labisia pumila VAR. alata)

Kacip Fatimah (Labisia pumila), an undershrub herb from the Myrsinaceae family, is traditionally used as medicine, particularly by Malay women during post-natal care. The development of L. pumila as a medicinal herb has led to its commercialization and increasing demand. To ensure its sustainable supply, the propagation of kacip Fatimah on a large scale such as through tissue culture needs to be explored. In this study, the leaves of a selected high yielding clone of kacip Fatimah, clone AA28, were used as explants. After surface sterilization, the explants were cultured on MS basal medium containing 0.5 mg/l NAA with different concentrations of BAP ranging from 0.05 to 0.15 mg/l for shoot induction. The explants cultured in MS medium containing 0.5 mg/l NAA in combination with 0.05 mg/l BAP produced the highest mean number of shoots per explants (10 ± 0.1). The shoot multiplication study is in progress and will be reported in a future paper

In vitro micropropagation of Acacia auriculiformis from selected juvenile sources

The effects of 6- Benzylaminopurine (BA), different basal medium, sucrose concentration and gelling agent were investigated for shoot induction and multiplication of Acacia auriculiformis. Nodal explants derived from 5-month-old seedlings yielded the highest shoot multiplication rate in Murashige and Skoog medium (MS) with 0.44 μM BA, 30 g/L sucrose and 2 g/L Gelrite. The highest mean number of shoots (10) and mean length of shoots (5.07mm) were also obtained in this medium. Qualitative observation of the shoots cultured in 0.44 μM BA were greener and vigorous in growth as compared to shoots cultured on higher concentrations of BA (22.2 μM). MS medium produced a significantly higher number of shoots (18) compared to Woody Plant Medium (WPM) (11) and B5 medium (10). Media solidified with different gelling agents also produced a significantly different number of shoots with 2 g/L Gelrite produced the highest number of shoots (23). The highest percentage of shoots rooted was found in the MS medium without any growth regulators (40.0%) followed by medium supplemented with Indole-3-butyric acid (IBA) at 9.84 μM and the combination of 9.84 μM IBA with 5.37 μM α-naphthalene acetic acid (NAA) (33.3%). MS medium without any plant growth regulators produced the highest mean root length (84.33mm), whereas medium supplemented with 9.84 μM IBA produced the highest mean number of roots per shoot (4.33). Out planting of in vitro rooted shoots in shredded coconut husk as the substrate gave the highest percentage of survival (90%) during acclimatization in the greenhouse