Micropropagation is an advanced tissue culture technique used to rapidly multiply disease-free, high-quality Aquilaria (agarwood) plants. This method is crucial for sustainable agarwood production, ensuring genetic uniformity and large-scale propagation without overharvesting wild populations.
Advantages of Micropropagation for Agarwood
Mass Production – Thousands of plants can be produced from a single explant.
Disease-Free Plants – Sterile conditions eliminate pathogens, improving plant health.
Faster Growth Rate – Plants develop rapidly, reducing the time to maturity.
Genetic Uniformity – Ensures high-yield agarwood-producing trees with consistent resin quality.
Year-Round Cultivation – Not limited by seasonal seed availability.
Step-by-Step Micropropagation Process
1. Selection of Explant (Starter Plant Tissue)
✔ Common explants: Shoot tips, nodal segments, or immature embryos.
✔ Source from healthy, mature Aquilaria trees to ensure high-quality clones.
✔ Surface sterilization:
- Wash explants in running water for 15–30 minutes.
- Soak in 0.1% Mercuric Chloride (HgCl₂) or Sodium Hypochlorite (NaOCl) for 10–15 minutes.
- Rinse thoroughly 3–5 times with sterile distilled water.
2. Initiation of Cultures (Establishment Phase)
✔ Place sterilized explants into Murashige & Skoog (MS) medium with growth regulators.
✔ Growth Hormones:
- For shoot induction: 0.5–2.0 mg/L BAP (6-Benzylaminopurine) or Kinetin.
- For callus induction: 1.0–3.0 mg/L 2,4-D (2,4-Dichlorophenoxyacetic acid).
✔ Maintain in dark conditions for the first 3–5 days, then shift to 16-hour light cycles at 25°C ± 2°C.
3. Multiplication Phase (Shoot Proliferation)
✔ Subculture shoots every 3–4 weeks to fresh MS medium.
✔ Adjust growth hormones to increase shoot multiplication:
- BAP + Kinetin (0.5–1.5 mg/L each) encourages multiple shoot formation.
✔ Maintain cultures in a growth chamber at 25°C with 16-hour light exposure.
✔ Within 4–6 weeks, multiple shoots develop from a single explant.
4. Rooting Phase (Root Induction & Plant Development)
✔ Transfer well-developed shoots to MS medium with auxins (IBA or NAA at 0.5–1.0 mg/L) for root formation.
✔ Keep in low light conditions for the first 5–7 days to encourage rooting.
✔ Once roots form, shift to normal light conditions (16-hour photoperiod).
5. Hardening & Acclimatization (Greenhouse Transfer)
✔ Transfer rooted plantlets to sterile potting mix (peat moss + vermiculite + perlite in 1:1:1 ratio).
✔ Keep in a high-humidity chamber or greenhouse for 2–4 weeks to prevent transplant shock.
✔ Gradually expose plants to external conditions before field planting.
Challenges & Solutions in Micropropagation
❌ Contamination Issues → Use strict sterilization protocols for explants & media.
❌ Slow Growth in Culture → Optimize growth hormones & light conditions.
❌ Low Rooting Success → Use IBA or NAA with auxin-rich media for better root induction.
❌ Acclimatization Failure → Gradually adjust plants to natural conditions with controlled humidity & shading.