| Abstract Detail
Developmental and Structural Section Strout, Greg W. [1], Russell, Scott D. [2], Lee, David [3]. Ultrastructual basis of blue interference color in leaves of Mapania caudata, a Malaysian tropical rainforest understory herb. A number of Malaysian tropical rainforest understory species produce brilliant blue color, due to layering that produces color through constructive interference. In flowering plants (species in Phyllagathis and Sonerila in the Melastomataceae and Begonia in the Begoniaceae) structural interference is due to modified epidermal plastids, termed iridoplasts. Mapania caudata Kük (Cyperaceae) is locally common in Malaysian forest understory, and its leaves are a beautiful iridescent blue. Analysis of diffuse reflectance of blue versus green leaves revealed a peak at ~480 nm. Assuming a refractive index (η) of ~1.4 for hydrated cellulose or thylakoid membranes, these plants would need structures with a spacing of 86 or 172 nm, depending upon an increase or decrease of η in the material. The cell walls of blue leaves have a pronounced layering of electron translucent and opaque layers with a periodicity of approximately 112 nm, and the electron opaque portion roughly corresponds with the predicted thickness. There is little evidence for a strong helicoidal structure, due to even angles of cellulose microfibril layering, which accounts for iridescence in beetle exocuticles as well as leaves in some ferns. The entire cell wall is permeated with silica, and it is possible that the silica deposition (with η of 1.46) promote conditions for interference coloration in these plants. Thus, the mode of structural color production in M. caudata is unique among the angiosperms.
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1 - University of Oklahoma, Samuel Roberts Noble Electron Microscopy Laboratory, Norman, OK, 73019, USA
2 - University of Oklahoma, Samuel Roberts Noble Electron Microscopy Laboratory and Department of Botany and Microbiology, Norman, OK, 73019, USA
3 - Florida International University, Deparment of Biological Sciences, Miami, FL, 33199, USA
Keywords:
constructive interference
leaf color
Mapania caudata
tropical rainforest
Malaysia
cell wall ultrastructure.
Presentation Type: Poster:Posters for BSA Sections
Session: P2
Location: Event Tent/Cliff Lodge
Date: Tuesday, July 28th, 2009
Time: 5:30 PM
Number: P2DS010
Abstract ID:931 |
