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Abstract Detail



Phytochemical Section

Busta, Lucas [1], Budke, Jessica M. [2], Jetter, Reinhard [3].

Cuticular waxes from the leafy gametophyte, sporophyte, and calyptra of the moss Funaria hygrometrica.

The plant cuticle is a multi-layered hydrophobic coating that promotes self-cleaning and slows dehydration, among other functions. It is comprised of lipids in the form of cutin and waxes. Structurally, the cuticle is a crosslinking cutin framework inside and on top of which the wax accumulates and forms the transpiration barrier. Cuticles with specialized function are known to exhibit unique microstructures, which are in turn the result of exceptional composition. However, details of the connection between the identity of the chemical compounds in the wax and any specialized cuticle function are not yet understood.
Mosses are ideal models with which to investigate this relationship because of their phase-based haploid lifecycle and protective maternal structures. Electron microscopy was recently used to examine the microstructure of the cuticles on the leafy gametophyte, sporophyte capsule, and calyptra of Funaria hygrometrica. The data obtained established that the protective role of the calyptra and the dehydration sensitivity of each organ are consistent with the thickness of the corresponding cuticle. These observations prompt the question: are the chemical compounds in the cuticular wax of the calyptra different from those found in the sporophyte and leafy gametophyte, and can they be correlated with the role of the calyptra as a specialized maternal protective structure?
Gas chromatographic and mass spectrometric analysis of the cuticular wax of the leafy gametophyte, sporophyte, and calyptra of F. hygrometrica and revealed that each had very low wax coverage, ranging from 1 to 8 ng/cm2, and that the coverages correlated roughly with anatomical cuticle thickness. Wax coverage was highest on the calyptra, indicating a positive correlation between coverage and protective ability. The chemical make-up of the wax differed between maternal and offspring organs, and may indicate that alkanes are a tool for long-term dehydration protection in the sporophyte. In addition, these measurements present the first opportunity by which to compare the wax coverage on mosses with that on vascular plants. Finally, in the course of the analysis, two novel chemical compound types were identified in the wax, which indicate that cuticle biosynthesis in F. hygrometrica is more similar to grasses and ferns than to flowering plants.


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1 - The University of British Columbia, Chemistry, 2036 Main Mall, Vancouver, BC, V6T1Z1, Canada
2 - University Of California - Davis, Department Of Plant Biology, One Shields Avenue, Davis, CA, 95616, USA
3 - The University of British Columbia, Chemistry, 2036 Main Mall, Vancouver, BC, V6T 1Z1, Canada

Keywords:
cuticle
wax
dehydration stress
maternal investment
calyptra
Bryophyte
gas chromatography
Mass Spectrometry.

Presentation Type: Oral Paper:Papers for Sections
Session: 30
Location: Salon 13/The Shaw Conference Centre
Date: Wednesday, July 29th, 2015
Time: 8:15 AM
Number: 30002
Abstract ID:1298
Candidate for Awards:None


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