{{Short description|Specialized structure of roots}}
In botany, '''pneumatodes''' are air-containing structures in plant roots.<ref>Rosa Belarbi-Halli, Jean Dexheimer, and François Mangenot. Le pneumatode chez ''Phoenix dactylifera'' L. I. Structure et ultrastructure. Canadian Journal of Botany. 61(5): 1367-1376. {{doi|10.1139/b83-146}}</ref> Their function is to allow gaseous exchange in root tissues. This can be beneficial to semi-aquatic plants, such as neo-tropical palms.<ref>J Balick, M. (1989). The Diversity Of Use Of Neotropical Palms.</ref> Plants with photosynthetic roots, such as epiphytic orchids like ''Dendrophylax lindenii'' also possess these structures. They play a role in fungal interactions.<ref>Chomicki, G., Bidel, L. P., & Jay-Allemand, C. (2014). Exodermis structure controls fungal invasion in the leafless epiphytic orchid Dendrophylax lindenii (Lindl.) Benth. ex Rolfe. Flora-Morphology, Distribution, Functional Ecology of Plants, 209(2), 88-94.</ref>
thumb|right|Pneumatodes on roots of a ''Vanda'' orchid thumb|Visualisation of pneumatodes on a root of ''Phalaenopsis philippinensis''
==Etymology== The name of the structure is derived from the Greek word πνεῦμα (pneûma), meaning breath and ὁδός (hodós), meaning pathway.<ref name= "Jaeger">{{cite book|last=Jaeger |first=Edmund Carroll |title=A source-book of biological names and terms |publisher=Thomas |publication-place=Springfield, Illinois |date=1959 |isbn=0-398-06179-3}}</ref>
==Fungal interactions== Fungal infections of plants may begin through penetration of the roots through pneumatodes.<ref>Chinchilla, C. M. ''Fusarium'' Wilt (''Fusarium oxysporum'' f. sp. ''elaeidis'') In Oil Palm: A Rather Weak Pathogen?.</ref>
==Functional 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).<ref>Rolleri, C., Deferrari, A. M., & del Carmen Lavalle, M. (1994). Epidermis y estomas porociclocíticos en Christensenia-cumingiana Crist (Marattiaceae-Marattiales-Eusporangiopsida). Revista del Museo de La Plata, 14(98), 207-218.</ref> Leafless orchids with photosynthetic roots rely on the gas exchange through pneumatodes for photosynthesis.
==Taxonomic 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.<ref>Balick, M. J. (1984). Ethnobotany of Palms in the Neotropics. Advances in Economic Botany, 1, 9–23. http://www.jstor.org/stable/43931365</ref> They can also be used in the field of paleobotany, as the structures may be preserved in fossilized roots.<ref>Plaziat, J. C. (1995). Modern and fossil mangroves and mangals: their climatic and biogeographic variability. Geological Society, London, Special Publications, 83(1), 73-96.</ref>
== References == {{Reflist}}
Category:Plant anatomy Category:Plant physiology Category:Plant roots