Stomata vs Hydathodes (A Comparison Table)
(Similarities and Differences between Stomata and Hydathodes)
Stomata and Hydathodes are specialized pores present in the aerial parts of plants associated with the release of water from the plant body to the surrounding environment.
Stomata: They are specialized pores present on the surface aerial plant parts especially on the lower epidermis of leaf, which facilitate Gaseous exchange and Transpiration. The stomatal pores are guarded by a pair of specialized epidermal cells called the Guard Cells. The guard cells can regulate the opening and closing of the stomatal pore and thereby regulate the gaseous exchange through the stomata.
Hydathode (Water Stomata): Hydathode is a secretory tissue commonly found in the leaves of Angiosperms. They are pore-like structures present on the leaf margin through which water is secreted out as droplets. This type of secretion is called Guttation.
The present post describes the Similarities and Differences between Stomata and Hydathodes with a Comparison Table
Similarities between Stomata and Hydathodes
Ø Both Stomata and Hydathodes are pores which opens to the exterior environment.
Ø Both are primarily present on leaves.
Ø Both stomata and hydathodes are completely composed of living cells.
Ø Both can release water to the atmosphere.
Difference between Stomata and Hydathodes
Sl. No. Stomata Hydathode
1 Stomata are associated with Transpiration. Hydathodes are associated with Guttation.
2 Stomata also facilitate exchange of gases like oxygen and carbon dioxide. Hydathodes do not have any role in the gaseous exchange in plants.
3 Stomata are present on the epidermis of leaf, young stem and floral parts. Hydathodes are present on the margins of leaf where the vascular supply (vein) ends.
4 Stomata are surrounded by a pair of specialized epidermal cells called Guard Cells. Hydathodes are surrounded by a ring of non-specialized cells.
5 The guard cells surrounding the stomata contain chloroplasts. The cells surrounding the hydathodes do not contain chloroplasts.
6 Stomata are subtended by a sub-stomatal cavity Hydathodes are subtended by a sub-epidermal cavity and mass of loosely packed parenchymatous cells called Epithem
7 Stomata are usually surrounded by two to many subsidiary cells. Subsidiary cells are absent around the hydathodes.
8 Stomata do not have any dependency with the vein ends of the leaves. Hydathodes are always associated with the vein ends of leaves.
9 Stomata remain closed at night and opened in the day time. Hydathodes always remain open (both day and night).
10 The opening and closing of stomata can be regulated by guard cells. There is no opening and closing mechanism for hydathodes, hence the hydathodes always remain open.