Abstract Detail

Carnivorous Plants: New Horizons in Hungry Foliage

Fritsch, Peter [1], Pereira, Caio [2], Almenara, Daniela [3], Winter, Carlos [3], Lambers, Hans [4], Almeda, Frank [1], Oliveira, Rafael [2].

Underground leaves of Philcoxia (Plantaginaceae) trap and digest nematodes.

The recently described genus Philcoxia comprises three species restricted to the Campos Rupestres of the Central Brazilian cerrado biome. The species of Philcoxia possess several unusual morphological features similar to those of some carnivorous species, especially a non-mycorrhizal and poorly developed root system, initially folded peltate leaf blades, capitate-sticky glands on the upper leaf surfaces, and scapose inflorescences. A striking additional feature is the placement of many of the minute leaves (0.5- to 1.5-mm blade diameter) under the surface of the white sand in which these plants grow. The combination of morphological features, the highly nutrient-impoverished substrate, and the observation of nematodes adherent to the surface of the leaves on herbarium specimens and in the field led to the hypothesis that the species of Philcoxia are carnivorous via leaf glands that trap nematodes and perhaps other soil organisms and absorb their nutritive content. Although initial tests with film emulsions did not detect the presence of exterior leaf proteases, more definitive nitrogen-uptake experiments in which ¹⁵N-labeled nematodes were applied to leaf surfaces, along with the detection of phosphatase activity on intact leaves, has provided compelling evidence of carnivory in Philcoxia. Morphological and molecular phylogenetic data place the genus solidly within the tribe Gratioleae of the Plantaginaceae, a large family (about 2000 species) in which carnivory is otherwise unknown. Philcoxia appears to be unique among carnivorous plants in trapping and digesting nematode prey with underground adhesive leaves. Whether this mechanism originated from terrestrial or aquatic ancestors within the Gratioleae remains uncertain because of limited phylogenetic taxon sampling and resolution. Our findings illustrate how much can still be discovered about the origin, distribution, and frequency of the carnivorous syndrome in angiosperms and, more generally, about the diversity of nutrient-acquisition mechanisms that have evolved in plants growing in severely nutrient-impoverished environments.

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1 - California Academy Of Sciences, 55 Music Concourse Drive, SAN FRANCISCO, CA, 94118-4503, USA
2 - Universidade Estadual de Campinas, Plant Biology Department, Institute of Biology, Campinas, SP, 13083-970, Brazil
3 - Universidade de São Paulo, Department of Parasitology, Institute of Biomedical Sciences, São Paulo, SP, 05508-900, Brazil
4 - University of Western Australia, School of Plant Biology, Crawley, 6009, Australia

Keywords:
plant carnivory
plant nutrient acquisition
campos rupestres
nitrogen
stable isotopes
Philcoxia
Plantaginaceae
nematodes.

Presentation Type: Symposium or Colloquium Presentation
Session: C2
Location: Knox/Hyatt
Date: Monday, July 9th, 2012
Time: 11:00 AM
Number: C2004
Abstract ID:1117