Annals of Botany 78: 537-545, 1996
© 1996 Annals of Botany Company
Morphology and Anatomy of Stems and Pedicels of Spring Flush Shoots Associated with Citrus Fruit Set
Department of Citriculture, Agricultural Research Organization, The Volcani Center, 6, Bet Dagan, 50250, Israel Food Science, Agricultural Research Organization, The Volcani Center, 6, Bet Dagan, 50250, Israel
August 15, 1995 ; November 10, 1995
Flowering and vegetative shoots of Shamouti orange [Citrus sinensis (L.) Osbeck] and Marsh seedless grapefruit (Citrus paradisi Macf.) were examined for correlation of their morphology and anatomy with fruit set. Fruit set is favoured on leafy inflorescences whereas abortion is nearly complete on leafless inflorescences. Leafless inflorescences of Shamouti with one flower were found to have a very thin stem which contained few vascular bundles, whereas those with three flowers had better-developed vascular systems. The vascular system of leafy inflorescences is significantly different from that of leafless ones and contains a distinct central xylem cylinder. The vascular area of leafless inflorescences is only about one-quarter of that of the leafy ones. The vascular system of grapefruit resembles that of the Shamouti orange. This study emphasizes the importance of the dimension of the vascular system for fruit set and provides a possible explanation for the better fruit set on both leafy and leafless inflorescences with several flowers compared with single-flowered inflorescences.
Anatomy; citrus; fruit set; leafless inflorescence; leafy inflorescence; pedicel; vascular system; vegetative shoot