Comparative anatomy of the absorption roots of terrestrial and epiphytic orchids

The present study compared roots of terrestrial and epiphytic Orchidaceae, analyzing the anatomical characteristics from an ecological point of view. The material was collected at three different sites in Minas Gerais / Brazil and was fixed in FAA. Transverse sections were obtained by freehand sections or from material previously embedded in Paraplast® or Historesin®. The prominent characteristics of the epiphytic group were: significant smaller perimeter, epidermis with 3 or more cell layers, U-thickened exodermal cell walls, O-thickened endodermal cell walls, and a low ratio between the caliber and the number of protoxylem arches. The terrestrial group presented simple or multiseriate epidermis, and exodermis and endodermis with typical Casparian strips. The anatomical characteristics should have evolved with several adaptations to distinct environments during evolutionary process.<br<O presente trabalho comparou raízes de Orchidaceae epífitas e terrestres, analisando as características sob um ponto de vista ecológico. O material foi coletado em três diferentes regiões de Minas Gerais/Brasil e fixado em FAA. Cortes transversais foram obtidos à mão livre ou em material infiltrado em Paraplast ou Historresina. As principais características do grupo epifítico foram: perímetro significativamente menor, epiderme com 3 ou mais camadas celulares, exoderme com espessamento em U, endoderme com espessamento em O e uma baixa razão entre o calibre e o número de pólos de protoxilema. O grupo terrestre apresentou epiderme simples ou bisseriada e exoderme e endoderme com estrias de Caspary. As características anatômicas podem estar envolvidas com diferentes adaptações aos distintos ambientes durante o processo evolutivo..

Medienart:

E-Artikel

Erscheinungsjahr:

2008

Erschienen:

2008

Enthalten in:

Zur Gesamtaufnahme - volume:51

Enthalten in:

Brazilian Archives of Biology and Technology - 51(2008), 1, Seite 83-93

Sprache:

Englisch

Beteiligte Personen:

Ana Sílvia Franco Pinheiro Moreira [VerfasserIn]
Rosy Mary dos Santos Isaias [VerfasserIn]

Links:

doi.org [kostenfrei]
doaj.org [kostenfrei]
www.scielo.br [kostenfrei]
Journal toc [kostenfrei]
Journal toc [kostenfrei]

Themen:

Adaptations
Anatomy
Biotechnology
Epiphytic
Orchids
Terrestrial

doi:

10.1590/S1516-89132008000100011

funding:

Förderinstitution / Projekttitel:

PPN (Katalog-ID):

DOAJ049864548