Does shade improve light interception efficiency? A comparison among seedlings from shade-tolerant and -intolerant temperate deciduous tree species

Authors

  • Sylvain Delagrange,

    1. Groupe de Recherche en Ecologie Forestière interuniversitaire (GREFi), Université du Québec à Montréal, C.P. 8888, Succ. Centre ville, Montréal, Québec, Canada, H3P 3P8;
    2. INRA UMR 1137 INRA – UHP Ecologie et Écophysiologie Forestières, 54280 Champenoux, France and Faculté des Sciences, UHP, 54500 Vandoeuvre, France;
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  • Pierre Montpied,

    1. INRA UMR 1137 INRA – UHP Ecologie et Écophysiologie Forestières, 54280 Champenoux, France and Faculté des Sciences, UHP, 54500 Vandoeuvre, France;
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  • Erwin Dreyer,

    1. INRA UMR 1137 INRA – UHP Ecologie et Écophysiologie Forestières, 54280 Champenoux, France and Faculté des Sciences, UHP, 54500 Vandoeuvre, France;
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  • Christian Messier,

    1. Groupe de Recherche en Ecologie Forestière interuniversitaire (GREFi), Université du Québec à Montréal, C.P. 8888, Succ. Centre ville, Montréal, Québec, Canada, H3P 3P8;
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  • Hervé Sinoquet

    1. INRA UMR INRA – UBP, Physiologie Intégrée de l’Arbre Fruitier et Forestier, PIAF, Site de Crouël, 234 Avenue du Brézet, 63100 Clermont-Ferrand, France
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Author for correspondence: Pierre Montpied Tel: +33 3 83 39 40 74 Fax: +33 3 83 39 40 22 Email: montpied@nancy.inra.fr

Summary

  • • Here, we tested two hypotheses: shading increases light interception efficiency (LIE) of broadleaved tree seedlings, and shade-tolerant species exhibit larger LIEs than do shade-intolerant ones. The impact of seedling size was taken into account to detect potential size-independent effects on LIE. LIE was defined as the ratio of mean light intercepted by leaves to light intercepted by a horizontal surface of equal area.
  • • Seedlings from five species differing in shade tolerance (Acer saccharum, Betula alleghaniensis, A. pseudoplatanus, B. pendula, Fagus sylvatica) were grown under neutral shading nets providing 36, 16 and 4% of external irradiance. Seedlings (1- and 2-year-old) were three-dimensionally digitized, allowing calculation of LIE.
  • • Shading induced dramatic reduction in total leaf area, which was lowest in shade-tolerant species in all irradiance regimes. Irradiance reduced LIE through increasing leaf overlap with increasing leaf area. There was very little evidence of significant size-independent plasticity of LIE.
  • • No relationship was found between the known shade tolerance of species and LIE at equivalent size and irradiance.

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