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Plasticité phénotypique inter et intra-annuelle de la croissance radiale et d’autres propriétés liées à la formation du cerne chez le mélèze

Abstract : Phenotypic plasticity is the ability of individual genotypes to adjust to environmental variation. In this thesis we used larch annual ring traits to estimate phenotypic plasticity at two-time scales: between years (chap. 1, inter-annual phenotypic plasticity) and within years (chap. 2, intra-annual phenotypic plasticity). In chap. 1 we analyzed annual rings of European larches distributed in four plots along a natural elevational gradient near Briançon, in the French Alps. The phenotypic plasticity of radial growth and latewood density as a function of maximum temperature tends to be negative at low elevation (1350 m) and distinctly positive at high elevations (2300 m), where European larch seems to react favorably to temperature increase. No elevation trend emerges for earlywood density, which mostly exhibits negative or null phenotypic plasticity. The phenotypic plasticity of mean ring density is intermediate between that of earlywood and of latewood density. In chap. 2 we used intra-annual radial growth curves recorded with automatic point dendrometers during four successive growing seasons in an experimental trial combiningseveral water regimes and three species of larch. From such curves we obtainedphenotypic plasticity variables for radial growth and the dynamics of water in the trunk as a function of several climatic variables. All phenotypic plasticity variables and all environmental conditions combined, hybrid larch is a little more plastic than Japanese larchand much more than European larch, which reflects its ability to quickly and efficiently replenish and use his water reserve. We hypothesize that this contributes to its greater vigor.In general, there are as many types of plasticity as there are combinations of phenotypic traits and environmental variable. Phenotypic plasticity summarizes in a single value all the dynamics of a particular response. While in natural selection a high plasticity seems to be an advantage, it is not so evident in artificial selection.
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Submitted on : Wednesday, April 7, 2021 - 12:14:28 PM
Last modification on : Friday, August 5, 2022 - 2:38:11 PM
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  • HAL Id : tel-03191597, version 1


Margarita Escobar Sandoval. Plasticité phénotypique inter et intra-annuelle de la croissance radiale et d’autres propriétés liées à la formation du cerne chez le mélèze. Sylviculture, foresterie. Institut agronomique, vétérinaire et forestier de France, 2020. Français. ⟨NNT : 2020IAVF0022⟩. ⟨tel-03191597⟩



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