What is Guttation?
Guttation is the appearance of water droplets on the tips and margins of leaves, usually visible in the early morning. Unlike dew (which condenses from the air), guttation water is pushed out from inside the plant by root pressure through special pores called hydathodes.
How It Works
- Night conditions: Transpiration stops because stomata are closed.
- Root pressure: Roots continue absorbing water, building pressure in the xylem.
- Hydathodes open: Specialized pores at leaf tips or margins release the excess water.
- Droplets form: Visible drops appear at leaf edges, often in a row along the margin.
When You See It
- Early morning: Before the sun warms the air and transpiration resumes.
- Humid nights: Lower evaporation allows droplets to accumulate.
- Young leaves: Guttation is more pronounced on young, actively growing leaves.
- Wet season: More common when soil moisture is high.
Guttation vs. Dew
| Feature | Guttation | Dew | | ----------- | --------------------------- | ------------------------- | | Source | From inside the plant | From atmospheric moisture | | Location | Leaf tips and margins | Entire leaf surface | | Composition | Contains dissolved minerals | Pure water | | Pattern | Droplets at specific pores | Uniform film |
Costa Rican Examples
Guttation is commonly observed in tropical species with large leaves:
- Balsa trees guttate profusely on humid mornings.
- Guarumo often shows large droplets at the tips of its palmate leaf lobes.
- Grasses and crops in the Central Valley regularly display guttation.
Why It Matters
- Plant physiology: Guttation indicates healthy root pressure and water transport.
- Disease: Guttation droplets can harbor and spread bacterial pathogens.
- Indicator: Absence of expected guttation may indicate root damage or drought stress.