Chemical Induction | SignalResin™ Inoculant | SignalResin™ Formulation | SignalResin™ Development | SignalResin™ Profile
Salicylic acid (SA) is a plant signaling molecule known for its role in systemic acquired resistance (SAR) and defense response activation. In the context of agarwood formation, salicylic acid is being explored and utilized as a chemical inducer to stimulate resin biosynthesis in Aquilaria species.
Mechanism of Action
Salicylic acid functions by mimicking a natural defense signal in plants. In Aquilaria, application of SA leads to:
- Activation of plant defense pathways
- Induction of reactive oxygen species (ROS)
- Upregulation of sesquiterpene and chromone biosynthesis
- Initiation of programmed cell death in target tissues, which is key to oleoresin formation
Application as Inoculant
Formulation Options:
| Type | Description |
|---|---|
| Pure SA | Crystalline powder, dissolved in ethanol or water |
| SA Solution (1–10 mM) | Commonly used for injection |
| SA + Co-inducers | Combined with ethylene, hydrogen peroxide, or Fusarium spores for synergistic effects |
Methods of Application:
- Syringe injection: Direct into drilled holes on trunk
- Infusion system: Gravity drip into boreholes (2–5 cm deep)
- Pressure-based systems: For deeper and uniform penetration
Efficacy in Research & Practice
Several studies (e.g., Gao et al., 2020; Hidayat et al., 2018) report that salicylic acid treatment leads to faster and more visible resin formation when compared to mechanical wounding alone.
Best results are often observed when SA is combined with:
- Fungal inoculants (e.g., Fusarium oxysporum)
- Manganese dioxide (MnO₂) to enhance ROS generation
- Jasmonic acid or ethylene for complex signaling
This supports a multi-signal induction model, where SA is a key component.
Sample Formulation for Field Use
SA-Based Induction Solution (per liter):
- Salicylic acid: 100–200 mg
- Ethanol (solvent): 20 mL
- Distilled water: up to 1 L
- Optional: MnO₂ (0.5–1 g), glucose (0.5%), Fusarium spores (if dual-action)
Adjust pH to ~6.0 for optimal uptake.
Considerations
| Factor | Impact |
|---|---|
| Tree age and size | Minimum 4–5 years for effective induction |
| SA concentration | Too high can be phytotoxic |
| Frequency | Typically applied once; resin formation monitored over 6–12 months |
| Environmental conditions | Humidity and temperature affect resin accumulation |