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Evidence for direct water absorption by the shoot of the desiccation-tolerant plant Vellozia flavicans in the savannas of central Brazil

Published online by Cambridge University Press:  25 July 2005

Rafael S. Oliveira
Affiliation:
Department of Integrative Biology, Valley Life Sciences Building, University of California – Berkeley, CA 94720 USA
Todd E. Dawson
Affiliation:
Department of Integrative Biology, Valley Life Sciences Building, University of California – Berkeley, CA 94720 USA
Stephen S. O. Burgess
Affiliation:
Department of Integrative Biology, Valley Life Sciences Building, University of California – Berkeley, CA 94720 USA School of Plant Biology, University of Western Australia, 35 Stirling Highway, Crawley WA 6009 Australia

Abstract

Our common view on water uptake by terrestrial plants is that it occurs via absorption by roots from the soil substrate. However, it has long been known that plants exhibit alternative water-absorption strategies, particularly in drought-prone environments. Examples include many tropical epiphytic orchids which use a specialized structure called velamen radicum around their aerial roots for moisture absorption directly from the air (Capesius & Barthlott 1975), specialized trichomes in bromeliads (Andrade 2003, Benzing 1990), uptake by hydathodes into leaves of species inhabiting dry desert ecosystems of Namibia (Martin & von Willert 2000) and foliar absorption by coastal California redwoods during the summer fog season (Burgess & Dawson 2004). One of the most intriguing and yet, least-studied examples of adaptations to severe water limitation is found with desiccation-tolerant plants (also called resurrection plants). During drought periods, the water content of these plants can equilibrate with the low relative humidity of the air to the point that the plants appear dead. However, when water is supplied, these plants fully rehydrate (Alpert 2000, Bewley & Krochko 1982) and become physiologically active. Desiccation-tolerant vascular plants are rare in most ecosystems but diverse in tropical inselbergs (granitic outcrops; Porembski & Barthlott 2000). Relatively little is known about inselberg species particularly from an ecophysiological perspective (see Lüttge 1997 and Klüge & Brulfert 2000 for reviews).

Type
Brief Report
Copyright
2005 Cambridge University Press

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