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Pneumatode

Specialized structure of roots

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In botany, pneumatodes are air-containing structures in plant roots. Their function is to allow gaseous exchange in root tissues. This can be beneficial to semi-aquatic plants, such as neo-tropical palms. Plants with photosynthetic roots, such as epiphytic orchids like Dendrophylax lindenii also possess these structures. They play a role in fungal interactions.

01Etymology

The name of the structure is derived from the Greek word πνεῦμα (pneûma), meaning breath and ὁδός (hodós), meaning pathway.

Visualisation of pneumatodes on a root of Phalaenopsis philippinensis
Visualisation of pneumatodes on a root of Phalaenopsis philippinensis

02Fungal interactions

Fungal infections of plants may begin through penetration of the roots through pneumatodes.

03Functional analogy to stomata

Pneumatodes are considered as a special type of cyclocytic stomata. The entire structure may rise above the adjacent epidermis. The pneumatodes may function as double structures for gas exchange and liquid water elimination (guttation). Leafless orchids with photosynthetic roots rely on the gas exchange through pneumatodes for photosynthesis.

04Taxonomic importance

These structures are characteristic for different species and can be used to differentiate between them. These features can be used to distinguish between palm species. They can also be used in the field of paleobotany, as the structures may be preserved in fossilized roots.

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Sources and credits

This article is adapted from the Wikipedia article Pneumatode, written by its contributors and licensed under CC BY-SA 4.0. Fathomly has changed the layout, removed citation markers, navigation and maintenance notices, and adjusted punctuation. This adapted version is shared under the same license. For references, see the original article.

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