Abstract Detail

Anatomy and Morphology

Teixeira-Costa, Luiza [1], Ceccantini, Gregorio [2].

What's in a name? That which we call a haustorium by any other name would cause misunderstanding of parasitic plant biology.

The parasitic life form in plants is associated with the formation of an organ generically called haustorium, which is responsible for the connection between parasite and host. The great diversity of parasitic species - about 1% of living angiosperms, added to the diversity of potential hosts results in a multiplicity of structures, tissues and cell types peculiar to these interactions. However, all this morpho-anatomical variety is often described under the use of few common terms. Such ambiguous terminology often leads to the implication of controversial homology. In order to promote a clearer and more precise use of terminology, we compiled several terms associated with the host-parasite interface and analyzed their meaning and use. The compilation process was initially based on a review paper published in 1977, from which 33 terms and their respective synonyms were selected. To these, 17 other entries were added based on more recent publications. Once selected, each term was analyzed regarding its original use and definition, as well as eventual resignifications through time. In addition, anatomical and ontogenetic studies have been carried out and compiled from the literature, then re- analyzed under the current phylogenetic perspective. A total of 50 terms are presented and discussed in this illustrated and referenced glossary. We suggest a standardization and an update of more adequate terms for the description of the parasite- host interface established by species in all different parasitic lineages. We discuss why the haustorium of parasitic plants should be understood as a complete organ, such as a root or a stem, which is composed of different tissues and cell types. The frequent equalization of this complete organ with one of its parts could lead to misunderstandings of the very parasitic nature of some species and lineages of parasitic plants. In addition, we highlight the need for caution when comparing structures formed by severely modified and reduced parasitic plants with those of free-living species. Further developmental studies analyzing these plants should broaden the current comprehension of their structure and evolution.

1 - Harvard University, Harvard University Herbaria, 22 Divinity Ave, Cambridge, MA, 02138, United States
2 - University of Sao Paulo, Department of Botany, 277 Rua do Matao, Sao Paulo, Brazil

Keywords:
parasitic plant
haustorium
Balanophoraceae
Orobanchaceae
Rafflesiaceae
mistletoe.

Presentation Type: Oral Paper
Session: AM1, Anatomy and Morphology
Location: Virtual/Virtual
Date: Wednesday, July 29th, 2020
Time: 11:15 AM
Number: AM1006
Abstract ID:252
Candidate for Awards:None