The key difference between transpiration and guttation is that transpiration is the loss of water vapor from the aerial parts of plants, mainly through stomata, while guttation is the exudation of liquid water, often containing minerals, from the tips or edges of leaves, usually occurring at night or in high humidity.
What is transpiration?
Transpiration is a botanical process where plants lose water, primarily through the stomata located on their leaves. These stomatal openings serve essential functions like enabling the entry of carbon dioxide for photosynthesis and the exit of oxygen during the same process.
While transpiration is often considered an unavoidable side effect of stomatal activity, some theories suggest that it also aids in water transportation within the plant and may help dissipate heat in direct sunlight through water evaporation. However, these hypotheses have faced challenges and are not universally accepted.
Excessive transpiration can be highly detrimental to a plant. When the rate of water loss surpasses the rate of water intake, it can hinder the plant’s growth and eventually lead to dehydration-induced death.
What is guttation?
Guttation is the process by which small herbaceous plants release water in the form of droplets through tiny pores called hydathodes found on the edges of their leaves. This phenomenon occurs mainly during the evening or early morning when the rate of water absorption by the plant’s roots exceeds the rate of water evaporation through transpiration from the leaves.
As a result, excess water accumulates in the plant’s tissues, which could potentially harm the cells. To prevent this damage, plants utilize hydathodes located at the tips of their veins to expel the surplus water, ensuring a balanced water regulation within the plant.
Interestingly, water has the remarkable ability to travel up to 2 feet through the plant’s xylem on its own, contributing to this process of guttation.
Transpiration vs Guttation
The primary difference between transpiration and guttation is given below:
| Aspect | Transpiration | Guttation |
| Occurs through | Stomata and lenticels. | Hydathodes. |
| Type of water loss | Water vapor. | Liquid water. |
| Time of occurrence | During the day. | During early morning or at night. |
| Temperature conditions | High temperatures. | Low temperatures. |
| Response to dry conditions | Favored by dry conditions. | Resisted by dry conditions. |
| Water lost through | Simple diffusion. | Not through diffusion. |
| Regulation mechanism | Controlled by stomata opening/closing. | Cannot be regulated, hydathodes don’t close. |
| Effect of humidity | Reduced rate during humid days. | Rate enhanced by humidity. |
| Involvement of root pressure | Not involved. | Vital role in the process. |
| Substances eliminated | Only pure water. | Sugars, salts, and amino acids. |