Developmental and Structural Section
Morawetz, Jeffery .
Comparative haustorial ultrastructure of hemiparasitic and holoparasitic Orobanchaceae.
The parasitic plant family Orobanchaceae presents an ideal system for studying the evolution of parasitism in plants. The family contains the full range of trophic capabilities from non-parasites to facultative and obligate hemiparasites and holoparasites. This parasiticability is conferred through an organ unique to parasitic plants: the haustorium. Direct xylem connections have been observed in all taxa examined;the width of the xylem bridge in haustoria is variable among the parasitic lineages in the family. However, a long-standing question about the structure of haustoria in Orobanchaceae remains unanswered: What are the structural modifications involved in phloem-to-phloem transfer between host and parasite? Here I examine the ultrastructure of two pairs of related taxa, each pair containing one hemiparasitic and one holoparasitic species. The proximity of host and parasite phloem differed between hemi- and holoparasites. The presence of transfer cells at the host-parasite interface, and plasmodesmatal connections between parasite and host cells at the interface will be discussed
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1 - Rancho Santa Ana Botanic Garden, 1500 North College Ave., Claremont, CA, 91711, USA
Presentation Type: Oral Paper:Papers for Sections
Location: Union D/Hyatt
Date: Tuesday, July 10th, 2012
Time: 2:15 PM