What is the difference between stomata and hydathodes?
Plants have specialized pores on the aerial parts for getting rid of excess water. These pores are stomata and hydathodes. Excess loss of water can lead to plant wilting.
The core difference between stomata and hydathodes is stomata are found on the epidermis of the leaves, stems, and fruits while hydathodes are found on the tips and margin of young leaves.
What Are Stomata?
Stomata are specialized pores present on the aerial part of the plant especially on the lower epidermis of the leaves. They are responsible for gaseous exchange and transpiration.
The opening and closing of stomata are controlled by guard cells. They are further divided into:
- Anomocytic Stomata
- Anisocytic Stomata
- Diacytic Stomata
- Paracytic Stomata
- Gramineous Stomata
What Are Hydathodes?
Hydathodes are pore-like structures located along the margin of the leaves and they secrete water droplets. They are quite common in angiosperm leaves.
Guttation is the process through which these leaves secrete water droplets and other substances out of the plant. They can either be active or passive hydathodes.
Comparison Chart: Stomata vs Hydathodes
| Basic Terms | Stomata | Hydathodes |
| Associated with | Associated with transpiration | Associated with guttation |
| Significance | Facilitate gaseous exchange in plants | Does not enhance the gaseous exchange |
| Location | Present on lower epidermis of the leaf, young stems and floral parts | Presence on the margin of the leaf where vascular supply vein meet |
| Surrounded by | Specialized epidermal cells known as guard cells | Ring of non-specialized cells |
| Chloroplast | Present in the guard cells | Absent |
| Subtended | Sub-stomatal cavity | Sub-epidermal cavity and mass of loosely packed parenchyma cells |
| Role of specialized cells | Opening and closing of stomata | No control of opening and closing of hydathodes |
| Cycle | Remain closed at night and open in the daytime | Tend to remain open throughout |
| Dependency | Do not depend on the end of the veins | Tend to be associated with the end of the veins |
| Subsidiary cells | Present | Absent |
| Types | Anomocytic Stomata Anisocytic Stomata Diacytic Stomata Paracytic Stomata Gramineous Stomata | Active hydathodes and Passive hydathodes |
| What They Pass Out | Stomata pass out water vapor. | Hydathode passes out liquid water. |
Core Differences between Stomata and Hydathodes In Point Form
- Stomata are found on the aerial part of the plants while hydathodes are found on the margin of the leaf
- Stomata are responsible for gaseous exchange and transpiration while hydathodes for guttation
- Stomata pass out water vapor while hydathode pass out water droplets
- Stomata are surrounded by guard cells while hydathodes by a ring of non-specialized cells
- Guard cells of stomata contain chloroplast while non-specialized cells of hydathodes do not
- Stomata are controlled by guard cells for opening and closing while hydathodes tend to remain open throughout
- Hydathodes depend on vascular bundles supply ends while stomata do not depend on any ends of veins
- Stomata tend to open in the day and close at night while hydathodes remain open throughout
- Stomata are surrounded by many subsidiary cells while hydathodes are not surrounded by subsidiary cells
- Stomata facilitate a gaseous exchange for photosynthesis while hydathodes do not facilitate gaseous exchange.
Similarities between Stomata and Hydathodes
- Both pores open to the exterior environment
- Both are found on the leaves
- Both compose of living cells
- Both release water to the atmosphere
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Comparison Video
Summary
Stomata are associated with transpiration and gaseous exchange while hydathodes are associated with guttation. Both specialized pores are found on the leaves and contain living cells.