Robinson, M., The Hebrew University of Jerusalem, Department of Ornamental Horticulture, Rehovot, Israel
Harav, I., The Hebrew University of Jerusalem, Department of Ornamental Horticulture, Rehovot, Israel
Halevy, A.H., The Hebrew University of Jerusalem, Department of Ornamental Horticulture, Rehovot, Israel
Plaut, Z., Institute of Soils and Water, Agricultural Research Organization, Volcani Center, Bet Dagan, Israel

The distribution pattern of the products of photosynthesis was studied in gladiolus plants (Gladiolus grandiflorus cv Eurovision) in four stages of development I, plants having a very young inflorescence still enclosed between the leaves; II, plants with a young inflorescence just emerged from the leaves, III, plants at full bloom, IV, plants with young fruits. The first, third or sixth foliage leaf was labelled with 14CO2, and subsequent distribution in the plant was determined Results were expressed as a percentage of translocated 14C accumulated by each part of the plant which gives a measure of its 'sink strength', or as 'relative sink activity' (RSA) which is independent of the size of the indicated organ.There are two competing sinks in the developing gladiolus-the inflorescence and the new corm. When RSA is the criterton the inflorescence constitutes the main sink irrespective of the source leaf from the first stage until flowering. With the subsequent wilting of the flowers and fruit set RSA of the inflorescence declines rapidly and the new corm becomes the main sink When 'sink strength' is the criterton it appears that the inflorescence acts as a very weak sink when it is young and becomes increasingly stronger until flowering and then declines steeply. Sink strength of the corm declines during the development of the inflorescence and then increases again steeply with wilting of the flowers and fruit set. There are small differences between the various source leaves. The young new corm acts as a strong sink for the lower foliage leaf and progressively weaker for upper leaves. © 1980 Annals of Botany Company.