| Abstract Detail
100 years of Baileyan Trends – Wood Evolution, Function and Future Dória , Larissa Chacon [1], Podadera, Diego [2], del Arco, Marcelino [3], Chauvin, Thibaud [4], Smets, Erik [5], Delzon, Sylvain [6], Lens, Frederic [7]. Insular woody daisies (Argyranthemum, Asteraceae) are more resistant to drought-induced hydraulic failure than their herbaceous relatives. Insular woodiness refers to the evolutionary transition from herbaceousness towards derived woodiness on (sub)tropical islands, and leads to island floras that have a higher proportion of woody species compared to floras of nearby continents. Several hypotheses have tried to explain insular woodiness since Darwin’s original observations, but experimental evidence why plants became woody on islands is scarce at best. Here, we combine experimental measurements of hydraulic failure in stems (as a proxy for drought stress resistance) with stem anatomical observations in the daisy lineage (Asteraceae), including insular woody Argyranthemum species from the Canary Islands and their herbaceous continental relatives. Our results show that stems of insular woody daisies are more resistant to drought-induced hydraulic failure than the stems of their herbaceous counterparts. The anatomical character that best predicts variation in embolism resistance is intervessel pit membrane thickness (TPM), which can be functionally linked with air bubble dynamics throughout the 3D vessel network. There is also a strong link between TPM vs degree of woodiness and thickness of the xylem fiber wall vs embolism resistance, resulting in an indirect link between lignification and resistance to embolism formation. Thicker intervessel pit membranes in Argyranthemum functionally explain why this insular woody genus is more embolism resistant to drought-induced failure compared to the herbaceous relatives from which it has evolved, but additional data are needed to confirm that palaeoclimatic drought conditions has triggered wood formation in this daisy lineage.
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1 - Naturalis Biodiversity Center, Botany / Understanding Evolution, Vondellaan 55, Leiden, 2332 AA, Netherlands
2 - UNICAMP, Campinas, SP, Brazil
3 - La Laguna University, Department of Plant Biology, La Laguna, Tenerife, Canary Islands, Spain
4 - University of Clermont Auvergne, INRA, Clermont-Ferrand, 63100 , France
5 - Naturalis Biodiversity Center, PO Box 9517, Leiden, 2300 RA, Netherlands
6 - University of Bordeaux, BIOGECO, INRA, Cestas, 33610 , France
7 - Naturalis Biodiversity Center, P.O. Box 9517, Leiden, 2300RA, Netherlands
Keywords:
Canary Islands
drought
hydraulic failure
insular woodiness
lignification
stem anatomy
thickness of intervessel pit membrane
xylem hydraulics.
Presentation Type: Colloquium Presentations
Session: C06, 100 years of Baileyan Trends - Wood Evolution, Function and Future
Location: 106/Mayo Civic Center
Date: Tuesday, July 24th, 2018
Time: 10:30 AM
Number: C06009
Abstract ID:137
Candidate for Awards:None |
