HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

What's this?

This Article Full Text Full Text (PDF) Submit a response Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in Web of Science Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Web of Science (14) Citing Articles via Google Scholar Google Scholar Articles by Pierce, S. Articles by Winter, K. Search for Related Content PubMed Articles by Pierce, S. Articles by Winter, K. Agricola Articles by Pierce, S. Articles by Winter, K. Social Bookmarking                            What's this?

Hydrophobic trichome layers and epicuticular wax powders in Bromeliaceae¹

Smithsonian Tropical Research Institute, Apartado 2072, Balboa, Panama City, Republic of Panama

The distinctive foliar trichome of Bromeliaceae has promoted the evolution of an epiphytic habit in certain taxa by allowing the shoot to assume a significant role in the uptake of water and mineral nutrients. Despite the profound ecophysiological and taxonomic importance of this epidermal structure, the functions of nonabsorbent trichomes in remaining Bromeliaceae are not fully understood. The hypothesis that light reflection from these trichome layers provides photoprotection was not supported by spectroradiometry and fluorimetry in the present study; the mean reflectance of visible light from trichome layers did not exceed 6.4% on the adaxial surfaces of species representing a range of ecophysiological types nor was significant photoprotection provided by their presence. Several reports suggesting water repellency in some terrestrial Bromeliaceae were investigated. Scanning electron microscopy (SEM) and a new technique—fluorographic dimensional imaging (FDI)—were used to assess the interaction between aqueous droplets and the leaf surfaces of 86 species from 25 genera. In the majority of cases a dense layer of overlapping, stellate or peltate trichomes held water off the leaf epidermis proper. In the case of hydrophobic tank-forming tillandsioideae, a powdery epicuticular wax layer provided water repellency. The irregular architecture of these indumenta resulted in relatively little contact with water droplets. Most mesic terrestrial Pitcairnioideae examined either possessed glabrous leaf blades or hydrophobic layers of confluent trichomes on the abaxial surface. Thus, the present study indicates that an important ancestral function of the foliar trichome in Bromeliaceae was water repellency. The ecophysiological consequences of hydrophobia are discussed.

Key Words: Bromeliaceae • epicuticular wax • fluorographic dimensional imaging • SEM • trichomes • water repellency

CiteULike    Complore    Connotea    Del.icio.us    Digg    Facebook    Reddit    Technorati    Twitter    What's this?

This article has been cited by other articles:

				T. J. Givnish Bromeliaceae: Profile of an Adaptive Radiation.--D. H. Benzing (with contributions from B. Bennet, G. Brown, M. Dimmitt, H. Luther, I. Ramirez, R. Terry and W. Till). 2000. Cambridge University Press, Cambridge, U.K. xii + 690 pp. ISBN 0-521-43031-3. $160.00 (hard cover). Syst Biol, April 1, 2005; 54(2): 340 - 344. [Full Text] [PDF]

				D. M. Crayn, K. Winter, and J. A. C. Smith Multiple origins of crassulacean acid metabolism and the epiphytic habit in the Neotropical family Bromeliaceae PNAS, March 9, 2004; 101(10): 3703 - 3708. [Abstract] [Full Text] [PDF]