Arinawa Liz Filartiga1, Adam Klimeš1,2, Jan Altman1,3, Michael Peter Nobis4, Alan Crivellaro5,6, Fritz Schweingruber4, Jiří Doležal1,7. 1. Institute of Botany, The Czech Academy of Sciences, Třeboň, Czech Republic. 2. Department of Botany, Faculty of Science, Charles University, Prague, Czech Republic. 3. Faculty of Forestry and Wood Sciences, Czech University of Life Sciences Prague, Prague 6 - Suchdol, Czech Republic. 4. Swiss Federal Research Institute WSL, Birmensdorf, Switzerland. 5. Department of Geography, University of Cambridge, Downing Place, Cambridge CB2 3EN, UK. 6. Forest Biometrics Laboratory, Faculty of Forestry, 'Stefan cel Mare' University of Suceava, Str. Universitatii 13, 720229 Suceava, Romania. 7. Faculty of Science, University of South Bohemia, České Budějovice, Czech Republic.
Abstract
BACKGROUND AND AIMS: Petioles are important plant organs connecting stems with leaf blades and affecting light-harvesting ability of the leaf as well as transport of water, nutrients and biochemical signals. Despite the high diversity in petiole size, shape and anatomy, little information is available regarding their structural adaptations across evolutionary lineages and environmental conditions. To fill this knowledge gap, we investigated the variation of petiole morphology and anatomy of mainly European woody species to better understand the drivers of internal and external constraints in an evolutionary context. METHODS: We studied how petiole anatomical features differed according to whole-plant size, leaf traits, thermal and hydrological conditions, and taxonomic origin in 95 shrubs and trees using phylogenetic distance-based generalized least squares models. KEY RESULTS: Two major axes of variation were related to leaf area and plant size. Larger and softer leaves are found in taller trees of more productive habitats. Their petioles are longer, with a circular outline and are anatomically characterized by the predominance of sclerenchyma, larger vessels, interfascicular areas with fibres and indistinct phloem rays. In contrast, smaller and tougher leaves are found in shorter trees and shrubs of colder or drier habitats. Their petioles have a terete outline, phloem composed of small cells and radially arranged vessels, fibreless xylem and lamellar collenchyma. Individual anatomical traits were linked to different internal and external drivers. Petiole length and vessel diameter increase with increasing leaf blade area. Collenchyma becomes absent with increasing temperature, and petiole outline becomes polygonal with increasing precipitation. CONCLUSIONS: We conclude that species' temperature and precipitation optima, plant height, and leaf area and thickness exerted a significant control on petiole anatomical and morphological structures not confounded by phylogenetic inertia. Species with different evolutionary histories but similar thermal and hydrological requirements have converged to similar petiole anatomical structures.
BACKGROUND AND AIMS: Petioles are important plant organs connecting stems with leaf blades and affecting light-harvesting ability of the leaf as well as transport of water, nutrients and biochemical signals. Despite the high diversity in petiole size, shape and anatomy, little information is available regarding their structural adaptations across evolutionary lineages and environmental conditions. To fill this knowledge gap, we investigated the variation of petiole morphology and anatomy of mainly European woody species to better understand the drivers of internal and external constraints in an evolutionary context. METHODS: We studied how petiole anatomical features differed according to whole-plant size, leaf traits, thermal and hydrological conditions, and taxonomic origin in 95 shrubs and trees using phylogenetic distance-based generalized least squares models. KEY RESULTS: Two major axes of variation were related to leaf area and plant size. Larger and softer leaves are found in taller trees of more productive habitats. Their petioles are longer, with a circular outline and are anatomically characterized by the predominance of sclerenchyma, larger vessels, interfascicular areas with fibres and indistinct phloem rays. In contrast, smaller and tougher leaves are found in shorter trees and shrubs of colder or drier habitats. Their petioles have a terete outline, phloem composed of small cells and radially arranged vessels, fibreless xylem and lamellar collenchyma. Individual anatomical traits were linked to different internal and external drivers. Petiole length and vessel diameter increase with increasing leaf blade area. Collenchyma becomes absent with increasing temperature, and petiole outline becomes polygonal with increasing precipitation. CONCLUSIONS: We conclude that species' temperature and precipitation optima, plant height, and leaf area and thickness exerted a significant control on petiole anatomical and morphological structures not confounded by phylogenetic inertia. Species with different evolutionary histories but similar thermal and hydrological requirements have converged to similar petiole anatomical structures.
Authors: Ian J Wright; Ning Dong; Vincent Maire; I Colin Prentice; Mark Westoby; Sandra Díaz; Rachael V Gallagher; Bonnie F Jacobs; Robert Kooyman; Elizabeth A Law; Michelle R Leishman; Ülo Niinemets; Peter B Reich; Lawren Sack; Rafael Villar; Han Wang; Peter Wilf Journal: Science Date: 2017-09-01 Impact factor: 47.728