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First published online December 16, 2005; 10.1104/pp.105.069724 Plant Physiology 140:176-183 (2006) © 2006 American Society of Plant Biologists Increased Accumulation of Cuticular Wax and Expression of Lipid Transfer Protein in Response to Periodic Drying Events in Leaves of Tree Tobacco1,[W]Faculty of Environmental and Forest Biology (K.D.C., L.B.S.) and Faculty of Chemistry (M.A.T.), State University of New York, College of Environmental Science and Forestry, Syracuse, New York 13210
Cuticular wax deposition and composition affects drought tolerance and yield in plants. We examined the relationship between wax and dehydration stress by characterizing the leaf cuticular wax of tree tobacco (Nicotiana glauca L. Graham) grown under periodic dehydration stress. Total leaf cuticular wax load increased after each of three periods of dehydration stress using a CH2Cl2 extraction process. Overall, total wax load increased 1.5- to 2.5-fold, but composition of the wax was not altered. Homologous series of wax components were classified into organic groups; n-hentriacontane was the largest component (>75%) with alcohols and fatty acids representing <10% of the entire wax load. An increase in density, but no change in the three-dimensional shape, of leaf wax crystals was evident under low-kV scanning electron microscopy after each drying event. Leaves excised from plants subjected to multiple drying events were more resistant to water loss compared to leaves excised from well-watered plants, indicating that there is a negative relationship between total wax load and epidermal conductance. Lipid transfer proteins (LTPs) are thought to be involved in the transfer of lipids through the extracellular matrix for the formation of cuticular wax. Using northern analysis, a 6-fold increase of tree tobacco LTP gene transcripts was observed after three drying events, providing further evidence that LTP is involved in cuticle deposition. The simplicity of wax composition and the dramatic wax bloom displayed by tree tobacco make this an excellent species in which to study the relationship between leaf wax deposition and drought tolerance.
1 This work was supported by the U.S. Department of Agriculture McIntire-Stennis Cooperative Forestry Research Program. The author responsible for distribution of materials integral to the findings presented in this article in accordance with the policy described in the Instructions for Authors (www.plantphysiol.org) is: Lawrence B. Smart (lbsmart{at}esf.edu). [W] The online version of this article contains Web-only data. Article, publication date, and citation information can be found at www.plantphysiol.org/cgi/doi/10.1104/pp.105.069724. * Corresponding author; e-mail lbsmart{at}esf.edu; fax 315–470–6934. Received August 9, 2005; returned for revision October 22, 2005; accepted October 24, 2005. This article has been cited by other articles:
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