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 Google Scholar Google Scholar Articles by Tennakoon, K. U. Articles by Maass, E. Search for Related Content PubMed Articles by Tennakoon, K. U. Articles by Maass, E. Agricola Articles by Tennakoon, K. U. Articles by Maass, E. Social Bookmarking                            What's this?

Structural attributes of the hypogeous holoparasite Hydnora triceps Drège & Meyer (Hydnoraceae)¹

²Department of Botany, University of Peradeniya, Peradeniya 20400, Sri Lanka; ³Department of Biological Sciences, Old Dominion University, Norfolk, Virginia 23529 USA; ⁴Department of Biology, University of Namibia, Windhoek, Namibia

ABSTRACT

The morphology of the hypogeous root holoparasite Hydnora triceps is highly reduced, and as with many holoparasites, the vegetative body is difficult to interpret. The vegetative body of H. triceps has been historically considered a "pilot root" studded with lateral appendages known as "haustorial roots." We found the vegetative body of H. triceps to consist of a rhizome with a thickened root-cap-like structure that covered a vegetative shoot apical meristem. From the apical meristem, procambial strands originated and developed into endarch collateral vascular bundles arranged radially around a pith without an interfascicular cambium. Xylem vessels had scalariform pitting and simple perforation plates. A continuous periderm without root hairs was observed. Increase in girth was attributed to cork and fascicular cambia. "Haustorial roots" or bumps on the surface of the vegetative body were exogenous, contained meristems and were the origins of vegetative branching, budding, and haustoria. The haustoria of H. triceps were cylindrical and penetrated the host root stele. Phloem and xylem elements were observed within the endophyte, and direct xylem to host-xylem contacts were observed. The arrangement of vascular tissues and xylem anatomy of H. triceps are likely plesiomorphic features in light of Hydnoraceae's placement in the Piperales.

Key Words: anatomy • haustoria • holoparasite • homeosis • Hydnora • Hydnoraceae • parasitic plants

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

This article has been cited by other articles:

				R. S. Seymour, E. Maass, and J. F. Bolin Floral thermogenesis of three species of Hydnora (Hydnoraceae) in Africa Ann. Bot., October 1, 2009; 104(5): 823 - 832. [Abstract] [Full Text] [PDF]

				K. J. Wurdack and C. C. Davis Malpighiales phylogenetics: Gaining ground on one of the most recalcitrant clades in the angiosperm tree of life Am. J. Botany, August 1, 2009; 96(8): 1551 - 1570. [Abstract] [Full Text] [PDF]