Plant Physiology & Development
Ethylene, Wounding & Stress Signaling
Ethylene is a gaseous plant hormone involved in responses to wounding, flooding, senescence, organ abscission, mechanical stress, and developmental processes. Its effects depend on concentration, tissue sensitivity, developmental stage, and interactions with other signals.
Key concepts
- Ethylene production can increase after wounding or other stress
- Mechanical training creates both structural change and wound-response signaling
- Low-oxygen root conditions can alter ethylene-related responses
- Senescing tissues often show coordinated hormone and nutrient-remobilization changes
- Hormone responses are networks rather than isolated switches
What to measure or observe
- Record training, pruning, transplant, or mechanical injury events
- Track wound closure and nearby tissue condition
- Check root-zone aeration when abnormal swelling, epinasty, or stress is suspected
- Compare damaged and undamaged branches
- Observe whether symptoms continue after the original stress has ended
Common mistakes
- Treating ethylene as the only explanation for any stress response
- Assuming visible wound swelling is always beneficial strengthening
- Ignoring root hypoxia in stress interpretation
- Applying hormone terminology without documenting the triggering event
- Confusing correlation with direct hormone measurement
Visuals this lesson still needs
- Wound-response signaling timeline
- Ethylene stress-response network
- Root hypoxia to shoot-response diagram
- Healing versus progressive injury comparison