tailieunhanh - Báo cáo toán học: "Carbon allocation among tree organs: A review of basic processes and representation in functional-structural tree models"

Tuyển tập các báo cáo nghiên cứu về lâm nghiệp được đăng trên tạp chí lâm nghiệp quốc tế đề tài: Carbon allocation among tree organs: A review of basic processes and representation in functional-structural tree models. | 521 Ann. For. Sci. 57 2000 521-533 INRA EDP Sciences Review Carbon allocation among tree organs A review of basic processes and representation in functional-structural tree models André Lacointe UMR PIAF INRA - Université Blaise Pascal Site de Crouel 234 Av. du Brézet 63039 Clermont-Ferrand Cedex 2 France Received 10 February 1999 accepted 21 July 1999 Abstract - Carbon assimilates flow from source areas such as leaves to sink areas where they are taken up and used. The assimilate fluxes from sources to sinks are mainly dependent on the source-sink distances and on the respective abilities of the different sinks to take up and use the assimilates that are available to them. The widely accepted basic mechanism of assimilate movement by mass-flow although conceptually simple has so far proved too complex for practical modeling purposes in whole tree systems. Four main modeling approaches can be found in current models i models involving empirically determined allocation coefficients ii models based on growth rules including functional balance or goal-seeking principles iii transport-resistance models iv models based on relative sink strength with two main sub-classes hierarchical and proportional models. These different model classes can be conceptually closer to each other than is readily apparent. They are presented in relation to their generality and ability to account for complex architectures or responses to environmental changes. The feedback relationship of allocation to growth is pointed out. assimilate partitioning source sink model Résumé - La repartition du carbone entre organes chez les arbres processus de base et representation dans les modèles structure-fonction . Les assimilats carbonés circulent de zones sources telles les feuilles vers des puits où ils sont préle-vés et utilisés. Ces flux d assimilats dépendent principalement des distances entre sources et puits ainsi que des capacités respectives des différents puits à prélever et utiliser les .