Developmental and Structural Section
Mickle, James , Barone Lumaga, Maria Rosaria , Moretti, Aldo , DeLuca, Paolo .
SEM studies of cuticle micromorphology in Cycas L. (Cycadacae).
Whole leaf and isolated cuticle specimens from Cycas L. were examined using SEM for features of inner and external surfaces and three-dimensional structure of the stomatal complex, useful characteristics in taxonomic determination. Samples were from the middle of leaflets from the midregion of mature leaves of greenhouse-grown Cycas revoluta Thunb., C. rumphii Miquel, C. circinalis L., C. media R. Brown and C. normanbyana Muell. Samples for external surfaces were air dried or fixed in FAA (10:5:50). Cuticles were isolated using 20% Cr2O3 to study their inner surface. Characteristics common to these species include hypostomy, abaxial and adaxial hair bases, adaxial cells randomly arranged, adaxial exterior cuticle smooth, and stomatal pit always formed by two layers of epidermal cells. Stomatal complexes polyperigenous, randomly oriented and dispersed and, except in C. revoluta, not contiguous. Stomata are deeply sunken in C. revoluta, intermediate in C. rumphii and C. normanbyana, and less sunken in C. circinalis and C. media. Aperture between guard cells extends the entire length of the stomatal complex in C. rumphii and C. normanbyana, about 80% in C. circinalis and C. media, and about 50% in C. revoluta. Based on cuticular features, C. revoluta shows the greatest number of differences from the other species, C. media and C. circinalis show the most similarity to each other and C. normanbyana and C. rumphii show the most similarity to each other. This contrasts with current taxonomy which places C. normanbyana in synonomy with C. media.
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1 - North Carolina State University, Department of Botany, Campus Box 7612, Raleigh, North Carolina, 27695-7612, USA
2 - Universitą di Napoli Federico II, Orto Botanico, via Foria, 223, Napoli, 80139, Italy
3 - Universitą di Napoli Federico II, Dipartimento di Biologia Vegetale, via Foria, 223, Napoli, 80139, Italy
4 - Universitą di Napoli Federico II, Orto Botanico, via Foria, 223, Napol
Presentation Type: Poster:Posters for Sections
Location: Exhibit Hall (Northeast, Southwest & Southeast)/Hilton
Date: Sunday, July 8th, 2007
Time: 8:00 AM