Bud structure in relation to shoot morphology and position on the vegetative annual shoots of Juglans regia L. (Juglandaceae)

The length and basal diameter of all lateral and terminal buds of vegetativ e annual shoots of 7-year-old Juglans regia trees were measured. All buds w ere dissected and numbers of cataphylls, embryonic leaves and leaf primordi a were recorded. Each axillary bud was ranked according to the position of its associated leaf from the apex to the base of its parent shoot. Bud size and content were analysed in relation to bud position and were compared wi th the size and number of leaves of shoots in equivalent positions which ex tended during the following growing season. Length and basal diameter of ax illary buds varied according to their position on the parent shoot. Termina l buds contained more embryonic leaves than any axillary bud. The number of leaves was smaller for apical and basal axillary buds than for buds in int ermediate positions on the parent shoot only. All new extended shoots were entirely preformed in the buds that gave rise to them. Lateral shoots were formed in the median part of the parent shoot. These lateral shoots derived from buds which were larger than both apical and basal ones. (C) 2000 Anna ls of Botany Company.