Abstract Detail

Developmental and Structural Section

Granados Mendoza, Carolina [1], Isnard, Sandrine [2], Charles-Dominique, Tristan [3], Van den Bulcke, Jan [4], Rowe, Nick P. [5], Van Acker, Joris [4], Goetghebeur, Paul [7], Samain, Marie-Stéphanie [8].

Bouldering: an alternative strategy to long-vertical climbing in root-climbing hortensias.

In the Neotropics, the genus Hydrangea of the popular ornamental hortensia family is represented by climbing species that strongly cling to their support surface by means of adhesive roots closely positioned along specialized anchoring stems. These root-climbing hortensia species belong to the nearly exclusive American Hydrangea section Cornidia and generally are long lianescent climbers that mostly flower and fructify high in the host tree canopy. The Mexican species Hydrangea seemannii, however, encompasses not only long lianescent climbers of large vertical rock walls and coniferous trees, but also short ‘shrub-like’ climbers on small rounded boulders. To investigate growth form plasticity in root-climbing hortensia species, we tested the hypothesis that support variability (e.g. differences in size and shape) promotes plastic responses observable at the mechanical, structural and anatomical level. Stem bending properties, architectural axis categorization, tissue organization and wood density were compared between boulder and long-vertical tree-climbers of H. seemannii. For comparison, the mechanical patterns of a closely related, strictly long-vertical tree-climbing species were investigated. Hydrangea seemannii has fine-tuned morphological, mechanical and anatomical responses to support variability suggesting the presence of two alternative root-climbing strategies that are optimized for their particular environmental conditions. Our results suggest that variation of some stem anatomical traits provides a buffering effect that regulates the mechanical and hydraulic demands of two distinct plant architectures. The adaptive value of observed plastic responses and the importance of considering growth form plasticity in evolutionary and conservation studies are discussed.

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Publication

1 - Instituto de Biología, Universidad Nacional Autónoma de México, Departamento de Botánica, Apartado Postal 70–367, Coyoacán 04510, Distrito Federal, Mexico, Mexico City, 04510, Mexico
2 - IRD, Centre IRD De Nouméa, B.P. A5, Nouméa, N/A, 98800, New Caledonia
3 - University of Cape Town, Department of Botany, Rondebosch 7701, Cape Town, South Africa, Cape Town, 7701, South Africa
4 - Faculty of Bioscience Engineering, Laboratory of Wood Technology, Ghen, Department of Forest and Water Management, Coupure Links 653, Ghent 9000, Belgium, Ghent, 9000, Belgium
5 - Université Montpellier 2, UMR AMAP, Montpellier, F-34000 France; CNRS, UMR AMAP, Montpellier, F-34000 France, Montpellier, 34000 , France
6 - Faculty of Bioscience Engineering, Laboratory of Wood Technology, Ghen, Department of Forest and Water Management, Coupure Links 653, Ghent 9000, Belgium, Ghent, 9000, Belgium
7 - Ghent University, Biology Department, K.L. Ledeganckstraat 35, Gent, 9000, Belgium
8 - Centro Regional del Bajío, Instituto de Ecología, A.C., Avenida Lázaro Cárdenas 253, Pátzcuaro 61600, Michoacán, Mexico, Pátzcuaro, 61600, Mexico

Keywords:
biomechanics
phenotypic accommodation
phenotypic plasticity
plant architecture
stem anatomy
wood densitometry.

Presentation Type: Oral Paper:Papers for Sections
Session: 76
Location: Salon 11/The Shaw Conference Centre
Date: Wednesday, July 29th, 2015
Time: 5:00 PM
Number: 76006
Abstract ID:467
Candidate for Awards:None