title: Hydraulic architecture correlates with bud organogenesis and primary shoot growth in beech (Fagus sylvatica).
abstract: In beech (Fagus sylvatica L.), the number of leaf primordia preformed in the buds determines the length and the type (long versus short) of annual growth units, and thus, branch growth and architecture. We analyzed the correlation between the number of leaf primordia and the hydraulic conductance of the vascular system connected to the buds. Terminal buds of short growth units and axillary buds of long growth units on lower branches of mature trees were examined. Buds with less than four and more than five leaf primordia formed short and long growth units, respectively. Irrespective of the type of growth unit the bud was formed on, the occurrence of a large number of leaf primordia was associated with high xylem hydraulic conductance. Xylem conductance was correlated to the area of the outermost annual ring. These results suggest that organogenesis and primary growth in buds correlates with secondary growth of the growth units and thus with their hydraulic architecture. Possible causal relationships between the variables are discussed.
authors.affiliation: UMR PIAF, INRA-UBP, INRA Site de Crouël, 234 avenue du Brézet, 63039 Clermont-Ferrand, France. cochard@clermont.inra.fr
authors.forename: Hervé
authors.initials: H
authors.lastname: Cochard
authors.forename: Sabrina
authors.initials: S
authors.lastname: Coste
authors.forename: Bernard
authors.initials: B
authors.lastname: Chanson
authors.forename: Jean Marc
authors.initials: JM
authors.lastname: Guehl
authors.forename: Eric
authors.initials: E
authors.lastname: Nicolini
mesh_terms: D002247:Carbon Isotopes / Q000378:metabolism; D029964:Fagus / Q000033:anatomy & histology* / Q000254:growth & development*; D018520:Plant Shoots / Q000033:anatomy & histology* / Q000254:growth & development*; D052584:Xylem / Q000033:anatomy & histology
chemical_list: D002247:Carbon Isotopes