AXILLARY SHOOT BUD DEVELOPMENT IN SELECTED ACTINIDIA SPECIES

Development of shoot buds of 10 Actinidia species from inception at bu dbreak to full-size, dormant buds is described as an important prerequ isite for understanding vine physiology. Bud diameter was measured, le af initials, and axillary structures were identified and counted with a dissecting microscope. Areas of the subtending leaves were measured. Both shoot bud size and leaf area decreased from the base to the tip of shoots. Shoot bud morphology was clearly affected by taxonomic grou ping. Shoot buds of genotypes in the Section Leiocarpae were small, wi th small ostioles, many small leaf initials, and no basal buds. Shoot buds of genotypes in the Sections Strigosae and Stellatae were compara tively large, with large ostioles, fewer leaf initials, and several ba sal buds. Shoot buds of A. arguta had no axillary structures. When the distribution of axillary structures was compared with the distributio n of axillary flowers on shoots, two patterns were noted. Either all t he primordia which would form flowers were already present in the shoo t bud or many or all of the primordia which would form flowers were no t present in the shoot bud.