Development and Structure
Schwallier, Rachel M. , Gravendeel, Barbara , de Boer, Hugo , van Heuven, Bertie Joan , Sieder, Anton , Sumail, Sukaibin , van Vugt, Rogier , Nylinder, Stephan , Lens, Frederic .
Evolution of wood anatomical characters in Nepenthes and close relatives in Caryophyllales.
Nepenthes, a carnivorous plant genus from Southeast Asia, attracts wide attention with its spectacularly shaped pitchers, cultural value and horticultural curiosity. Despite the plants’ iconic intrigue, surprisingly little anatomical detail is known about the genus beyond its modified leaf tip traps. We investigated the wood anatomy of 40 Nepenthes species to (i) assess the evolution of these characters within the genus and within a broader Caryophyllales framework, and (ii) to relate wood anatomical characters with variation in developmental stages, growth habit and abiotic preferences. Wood anatomical observations were performed using light microscopy (LM) and scanning electron microscopy (SEM). Ancestral states of evolutionary significant wood and pith characters were reconstructed using an existing molecular phylogenetic framework for Nepenthes, the non-core Caryophyllales clade and beyond. Pairwise comparisons were assessed for possible relationships between wood anatomy and developmental stages, growth habits, substrates and ecology. For Caryohpyllales, silica grains, successive cambia, bordered perforation plate and helically banded idioblasts appear to be the results of convergent evolution. In fact, peculiar helical sculpturing patterns within various cell types occur within the insectivorous clade of non-core Caryophyllales. Nepenthes are no exception, harbouring unique helically-banded idioblasts in the cortex and occasionally in multiseriate rays. Amongst Nepenthes, occasional septate fibres and pith lignification appear plesiomorphic. Most Nepenthes have some level of pith lignification. The wood anatomy of Nepenthes is characterised by diffuse porosity, mainly solitary vessels showing simple, bordered perforation plates and alternate intervessel pits, fibres with distinctly bordered pits which occasionally show septa, diffuse-in-aggregates to banded axial parenchyma and a combination of uni- and narrow multiseriate rays often including silica bodies. Abiotic conditions (soil type and precipitation) and growth habit (plant length)correlated with anatomical wood variation, especially in reference to multiseriate ray height and width, vessel diameter and presence of silica grains. The helical-banded fibre-sclereids that occur idioblastically in the pith and the cortex are synapomorphic for Nepenthes. Other typical Nepenthes characters, such as silica grains and bordered perforation plates, evolved convergently in different Caryophyllales lineages.
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1 - Naturalis Biodiversity Center, Darwinweg 2, Leiden, 2333 CR, The Netherlands
2 - Naturalis Biodiversity Center
3 - Uppsala University
4 - University of Vienna
5 - Sabah Park Herbarium
6 - Hortus botanicus, Leiden
7 - Swedish Museum of Natural History
8 - Naturalis Biodiversity Center, Leiden University, P.O. Box 9514, Leiden, N/A, 2300RA, Netherlands
ancestral state reconstruction
Presentation Type: Oral Paper
Session: 29, Development and Structure I
Location: 202/Savannah International Trade and Convention Center
Date: Tuesday, August 2nd, 2016
Time: 4:00 PM
Candidate for Awards:Katherine Esau Award,Maynard F. Moseley Award