@article {2345, title = {Phylogenetic ecology of leaf surface traits in the milkweeds (Asclepias spp.): chemistry, ecophysiology, and insect behavior}, journal = {New Phytologist}, volume = {183}, number = {3}, year = {2009}, note = {ISI Document Delivery No.: 472AKTimes Cited: 4Cited Reference Count: 89Agrawal, Anurag A. Fishbein, Mark Jetter, Reinhard Salminen, Juha-Pekka Goldstein, Jessica B. Freitag, Amy E. Sparks, Jed P.}, pages = {848-867}, type = {Article}, abstract = {P>The leaf surface is the contact point between plants and the environment and plays a crucial role in mediating biotic and abiotic interactions. Here, we took a phylogenetic approach to investigate the function, trade-offs, and evolution of leaf surface traits in the milkweeds (Asclepias). Across 47 species, we found trichome densities of up to 3000 trichomes cm(-2) and epicuticular wax crystals (glaucousness) on 10 species. Glaucous species had a characteristic wax composition dominated by very-long-chain aldehydes. The ancestor of the milkweeds was probably a glaucous species, from which there have been several independent origins of glabrous and pubescent types. Trichomes and wax crystals showed negatively correlated evolution, with both surface types showing an affinity for arid habitats. Pubescent and glaucous milkweeds had a higher maximum photosynthetic rate and lower stomatal density than glabrous species. Pubescent and glaucous leaf surfaces impeded settling behavior of monarch caterpillars and aphids compared with glabrous species, although surface types did not show consistent differentiation in secondary chemistry. We hypothesize that pubescence and glaucousness have evolved as alternative mechanisms with similar functions. The glaucous type, however, appears to be ancestral, lost repeatedly, and never regained; we propose that trichomes are a more evolutionarily titratable strategy. New Phytologist (2009) 183: 848-867doi: 10.1111/j.1469-8137.2009.02897.x.}, keywords = {adaptation to arid environments, ALDEHYDES, CARBON ISOTOPE DISCRIMINATION, cardenolides, CHARACTERS, CHEMICAL-COMPOSITION, cuticular, cuticular waxes, DISCRETE, EPICUTICULAR WAX CRYSTALS, EVOLUTION, IN-VITRO RECONSTITUTION, LEAVES, monarch butterfly caterpillar (Danaus plexippus), plant defense, STRATEGIES, syndromes, trichomes, UV PHOTOPROTECTION, water use efficiency, waxes}, isbn = {0028-646X}, url = {://000268100800031}, author = {Agrawal, A. A. and Fishbein, M. and Jetter, R. and Salminen, J. P. and Goldstein, J. B. and Freitag, A. E. and Sparks, J. P.} } @article {1626, title = {Nanotubules on plant surfaces: Chemical composition of epicuticular wax crystals on needles of Taxus baccata L}, journal = {Phytochemistry}, volume = {67}, number = {16}, year = {2006}, note = {ISI Document Delivery No.: 090QVTimes Cited: 13Cited Reference Count: 24Wen, Miao Buschhaus, Christopher Jetter, Reinhard}, month = {Aug}, pages = {1808-1817}, type = {Article}, abstract = {Needles of Taxus baccata L. were covered with tubular epicuticular wax crystals varying in diameters (100 and 250 nm) and lengths (300-500 and 500-1000 nm) on the abaxial and adaxial surfaces, respectively. Various sampling protocols were employed to study the chemical composition of the needle waxes on three different levels of spatial resolution. First, a dipping extraction of whole needles yielded the total cuticular wax mixture consisting of very long chain fatty acids (21\%), alkanediols (19\%), phenyl esters (15\%), and secondary alcohols (9\%) together with small amounts of aldehydes, primary alcohols, alkanes, alkyl esters, and tocopherols. Second, waxes from both sides of the needle were sampled separately by brushing with CHCl3-soaked fabric glass. Both sides showed very similar qualitative composition, but differed drastically in quantitative aspects, with nonacosan-10-ol (18\%) and alkanediols (33\%) dominating the abaxial and adaxial waxes, respectively. Third, the epi- and intracuticular wax layers were selectively sampled by a combination of mechanical wax removal and brushing extraction. This provided direct evidence that the tubular wax crystals contained high percentages of nonacosane-4,10-diol and nonacosane-5,10-diol on the abaxial surface, and nonacosan-10-ol on the adaxial surface of the needles. Together with these compounds, relatively large amounts of fatty acids and smaller percentages of aldehydes, primary alcohols, alkyl esters, and alkanes co-crystallized in the epicuticular layer. In comparison, the intracuticular wax consisted of higher portions of cyclic constituents and aliphatics with relatively high polarity. The formation of the tubular crystals is discussed as a spontaneous physicochemical process, involving the establishment of gradients between the epi- and intracuticular wax layers and local phase separation. (c) 2006 Elsevier Ltd. All rights reserved.}, keywords = {composition, CUTICULAR WAX, IN-VITRO RECONSTITUTION, LEAF CUTICULAR WAXES, LEAVES, SECONDARY ALCOHOLS, SURFACE, Taxaceae, Taxus baccata, yew needles}, isbn = {0031-9422}, url = {://000240966900015}, author = {Wen, M. and Buschhaus, C. and Jetter, R.} }