If self-shading is so bad, why is there so much? Short shoots reconcile costs and benefits

De Haldat Du Lys Alexandre, Millan Mathilde, Barczi Jean-François, Caraglio Yves, Midgley Guy F., Charles‐Dominique Tristan. 2023. If self-shading is so bad, why is there so much? Short shoots reconcile costs and benefits. New Phytologist, 237 (5) : 1684-1695.

https://doi.org/10.1111/nph.18636

Article de revue ; Article de recherche ; Article de revue à facteur d'impact

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Url - jeu de données - Entrepôt autre : https://doi.org/10.5061/dryad.79cnp5hzh

Résumé : If trees minimize self-shading, new foliage in shaded parts of the crown should remain minimal. However, many species have abundant foliage on short shoots inside their crown. In this paper, we test the hypothesis that short shoots allow trees to densify their foliage in self-shaded parts of the crown thanks to reduced costs. Using 30 woody species in Mediterranean and tropical biomes, we estimated the contribution of short shoots to total plant foliage, calculated their costs relative to long shoots including wood cost and used 3D plant simulations calibrated with field measurements to quantify their light interception, self-shading and yield. In species with short shoots, leaves on short shoots account for the majority of leaf area. The reduced cost of short stems enables the production of leaf area with 36% less biomass. Simulations show that although short shoots are more self-shaded, they benefit the plant because they cost less. Lastly, the morphological properties of short shoots have major implications for whole plant architecture. Taken together, our results question the validity of only assessing leaf costs to understand leaf economics and call for more integrated observations at the crown scale to understand light capture strategies in woody plants.

Mots-clés Agrovoc : morphologie végétale, feuille, photosynthèse, surface foliaire, croissance, anatomie végétale, plante ligneuse, bois tropical, Houppier, tige, port de la plante, bilan radiatif, lumière