Brazilian Journal of Botany

, Volume 38, Issue 2, pp 411–415 | Cite as

Spiral root hairs in Spiranthinae (Cranichideae: Orchidaceae)

  • Angelita Aparecida Bernal
  • Eric de Camargo Smidt
  • Cleusa BonaEmail author


(Spiral Root Hairs in Spiranthinae (Cranichideae: Orchidaceae) Root hairs are extensions of root epidermal cells, usually unicellular and unbranched. Root hairs studies usually focus on the relevant physiological and molecular aspects and have become a well-studied model of cellular differentiation and growth. In the Orchidaceae structures such as velamen, as well as exodermal and endodermal thickening, have been considered taxonomically valuable for categorizing different groups. While velamen has been greatly studied and discussed, root hairs are rarely mentioned in the literature or are merely characterized as simple root hairs. In the present study, we characterize morphologically spiral root hairs in a broad sample species of Spiranthinae. We analyzed roots from 23 species included in 12 genera from the subtribe Spiranthinae and Prescottia stachyodes (Sw.) Lindl. (Cranichidinae) as an external group, using light microscopy and scanning electron microscopy. Spiral root hairs are a continuation of the velamen and are found among simple root hairs; they differ from the latter in the type of wall rupture displayed. Spiral root hairs occur frequently among the species we analyzed, in both epiphytic as well as terrestrial species. We believe these root hairs help increase the opening (facilitating the entrance of colonizers), improve fluid absorption, and increase adherence to the substrate. The presence of spiral root hairs may also carry taxonomic importance in studies with a broader sample of Orchidoideae.


Root anatomy Type of root hairs Wall thickenings 



We thank Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) for funding this project (PNADB 998/2010) and providing financial support for the first author. We thank the Center for Electron Microscopy at UFPR for allowing us to use their equipment, and Jaques Klein for providing us some of the samples.


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Copyright information

© Botanical Society of Sao Paulo 2015

Authors and Affiliations

  • Angelita Aparecida Bernal
    • 1
  • Eric de Camargo Smidt
    • 1
  • Cleusa Bona
    • 1
    Email author
  1. 1.Departamento de Botânica/Setor de Ciências BiológicasUniversidade Federal do Paraná - UFPRCuritibaBrazil

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