3.4 Role of Manganese, Iron, and Stress Ions in Agarwood Resin Induction

1. What Are Stress Ions?

Stress ions are minerals like manganese (Mn²⁺), iron (Fe³⁺/Fe²⁺), and other trace metals that can create mild stress inside the tree.

  • They don’t produce resin directly
  • They trigger the tree’s defense system
  • Often applied via chemical elicitors in drilled holes

2. Role of Manganese (Mn²⁺)

  • Acts as a cofactor in enzyme reactions
  • Helps produce oxidative stress signals
  • Boosts secondary metabolites like sesquiterpenes
  • Enhances resin polymerization

Farmer tip:

Use in low concentration; excess Mn can burn tissues.

3. Role of Iron (Fe³⁺ / Fe²⁺)

  • Important in oxidation–reduction reactions
  • Strengthens the tree’s reactive oxygen burst
  • Supports chromone formation
  • Helps the tree maintain localized defense

Farmer tip:

Combine with wounding; avoid dripping on leaves.

4. Other Stress Ions

  • Calcium (Ca²⁺), Magnesium (Mg²⁺), Zinc (Zn²⁺) can also act as stress signals
  • Promote cell wall reinforcement and resin deposition
  • Help the tree isolate wounded areas

5. Why Controlled Dose Matters

IonFunctionRisk if Overused
ManganeseEnzyme cofactor, oxidative stressTissue necrosis, leaf drop
IronROS signaling, chromone supportLocal burn, tree death
Calcium/ZincStructural support, resin formationWeak tissue or toxicity

6. How Farmers Use Stress Ions

  1. Drill small holes in the trunk
  2. Inject a diluted solution of Mn²⁺, Fe³⁺, or combined ions
  3. Seal hole to prevent contamination
  4. Monitor for resin zone development over months
  5. Combine with microbial inoculation for best quality resin

Farmer Key Message

“Stress ions tell the tree: defend yourself.
The tree responds by making resin — the more carefully we apply, the better the resin.”