What is Guttation?
Guttation (pronunciation: guh-tay-shun) in plants refers to the appearance of water droplets on the leaf edges or tips, typically during the late evening or early morning. These droplets often contain dissolved minerals and sugars, making them different from dew, which comes directly from the condensation of atmospheric moisture. Dew is purely atmospheric water, while guttation droplets originate inside the plant and exit through specialised leaf pores.
Mechanism of Guttation
Guttation in plants commonly occurs when there is high humidity and abundant water supply in the soil. In such conditions, the roots absorb water continuously, creating a pressure known as root pressure. This pressure pushes water upwards through the xylem and forces it out through tiny pores called hydathodes found at the margins or tips of leaves. This phenomenon is sometimes called hydathode guttation.
Key Points:
Occurs mainly at night or early morning when stomata (tiny openings on leaves) are closed, reducing or stopping transpiration.
The expelled fluid contains minerals and organic compounds, leaving a whitish residue after evaporation.
Guttation usually happens in herbaceous plants like grasses, strawberries, and certain ornamental plants.
Guttation vs Transpiration
Although both involve water movement in plants, guttation vs transpiration are distinct processes. Below is a brief comparison:
Unique Insights on Guttation
Confusion with Dew: Guttation droplets can look like dew, but dew forms on the leaf surface from external atmospheric moisture, whereas guttation fluid is pushed out from within the plant.
Nutrient Cycling: Since guttation droplets contain minerals, they can help to redistribute nutrients on the leaf surface, although this effect is generally minor.
Impact on Garden Plants: If you notice watery droplets on your houseplants or in your garden early in the morning, it might be guttation. It usually does not harm the plant.
Relation to Humidity: High humidity and moist soil are ideal for guttation because transpiration is minimal, allowing root pressure to build up and push water out.
Quiz Time!
Test your understanding of guttation:
Which plant tissues generate the pressure that drives guttation?
A. Root Pressure
B. Stem Pressure
C. Leaf Pressure
D. Flower Pressure
Answer: A. Root Pressure
Where do guttation droplets mainly exit from the plant?
A. Hydathodes
B. Bark
C. Petals
D. Flower buds
Answer: A. Hydathodes
Which statement is true about guttation?
A. The water lost is 100% pure.
B. It occurs mostly in the afternoon.
C. It happens through stomata only.
D. Guttation droplets contain minerals and sugars.
Answer: D. Guttation droplets contain minerals and sugars.
FAQs on Guttation in Plants: Definition, Mechanism and Key Differences
1. Can guttation harm plants if it happens too often?
Guttation itself usually does not harm plants. However, if the soil remains excessively wet, it can lead to root problems like fungal growth or rot. Ensuring proper drainage helps keep plants healthy.
2. Why are guttation droplets often sticky or leave a white residue?
The droplets contain dissolved minerals, sugars, and other compounds. As the water evaporates, these substances remain, forming a sticky or white crust on the leaf surface.
3. Is guttation more common in certain types of plants?
It is more frequently observed in herbaceous plants like grasses, tomatoes, and strawberries. Woody plants typically do not display guttation as prominently.
4. Is guttation the same as bleeding or exudation of sap from stems?
No. Bleeding or exudation of sap usually occurs when a stem is cut or damaged, whereas guttation is a natural excretion of water droplets through hydathodes on leaf edges.
5. What is the difference between guttation and dew formation?
Dew is atmospheric moisture that condenses on the leaf surface. Guttation, on the other hand, is water exuded from inside the plant, pushed out by root pressure.
