Differences in leaf traits among sixteen Eucalyptus genotypes suggest contrasting strategies to cope with climatic conditions

Nogueira Raoni, Rodrigues Tatiane, Camargo Campoe Otávio, Nouvellon Yann, Laclau Jean-Paul, Le Maire Guerric, Stape Jose Luiz. 2018. Differences in leaf traits among sixteen Eucalyptus genotypes suggest contrasting strategies to cope with climatic conditions. In : Eucalyptus 2018: Managing Eucalyptus plantation under global changes. Abstracts book. CIRAD, IUFRO, MUSE. Montpellier : CIRAD, Résumé, 157-158. ISBN 978-2-87614-743-0 Eucalyptus 2018, Montpellier, France, 17 Septembre 2018/21 Septembre 2018.

Résumé : Eucalyptus plantations in Brazil cover approximately 5,7 million hectares and are distributed from 0O to 32O S, covering a wide range of climatic conditions. To develop adapted genotypes to this climatic gradient, breeding programs use species with different leaf anatomic, morphologic and structural traits. We selected 16 highly planted Eucalyptus genotypes (E.grandis, E.urophylla, E.camaldulensis, E.saligna, pure and hybrids, clonal and seed-origin) across different regions in Brazil, and grew them at a single location to assess their genotypic variability in leaf structure, anatomy and morphology, and how these leaf traits may be related to strategies to cope with environmental conditions. Most genotypes exhibited similar leaf anatomy, with about 5% of leaf thickness constituted of cuticles, 11% of epidermis, 26% of palisade parenchyma, and 58% of spongy parenchyma. The only exception was the clone E.grandis x E.camaldulensis, with no spongy parenchyma and thick palisade parenchyma (84% of the leaf thickness). The clones had hypostomatic leaves, except two genotypes with amphistomatic leaves (E.grandis x E.camaldulensis and E.grandis). Significant relationships were found between leaf inclination angle (LIA) and shape, and stomatal density and size. Genotypes with lower leaf area per tree showed higher mean LIA (R2=0.23, p< 0.05). Negative correlations were also found across genotypes between stomatal density and stomatal size (R2=0.67, p< 0.001), and between LIA and stomatal density (R2=0.61, p< 0.001). Genotypes with higher LIA showed more narrow and long leaves (R2=0.57, p< 0.001). From wetter to drier conditions in the regions where the clones were selected, the main trend was a decrease in leaf area per tree and in stomatal density per area of leaf, as well as an increase in LIA, and stomatal size. Improving our understanding of the trade-offs among leaf traits can help tree breeding programs to select genotypes able to cope with specific climatic conditions.

Mots-clés libres : Eucalyptus, Sustainability, Ecosystem services, Abiotic stresses, Biotic stresses, Plantation project

Auteurs et affiliations

• Nogueira Raoni, UNESP (BRA)
• Rodrigues Tatiane, UNESP (BRA)
• Camargo Campoe Otávio, UFSC (BRA)
• Nouvellon Yann, CIRAD-PERSYST-UMR Eco&Sols (THA) ORCID: 0000-0003-1920-3847
• Laclau Jean-Paul, CIRAD-PERSYST-UMR Eco&Sols (FRA) ORCID: 0000-0002-2506-214X
• Le Maire Guerric, CIRAD-PERSYST-UMR Eco&Sols (BRA) ORCID: 0000-0002-5227-958X
• Stape Jose Luiz, USP (BRA)

Source : Cirad-Agritrop (https://agritrop.cirad.fr/589558/)

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