ANNUAL DEVELOPMENT AND FLOROGENESIS OF LEUCADENDRON 'SAFARI SUNSET' IN ISRAEL

Abstract

The production of ornamental branches of Leucadendron 'Safari Sunset' in the northern regions of Israel resulted in the export of 23 million stems to the European and American market in 2006. The economic value of this crop is provided by the deep red color of the involucral leaves and its typical head form. In this research, reproductive development of 'Safari Sunset' was studied during the annual crop life cycle. The transition from the vegetative to the reproductive stage occurs in the autumn, and individual flowers develop in the axils of the inflorescence bracts. In the early stages of differentiation, flowers of 'Safari Sunset' contain both female and male organs. Exposure to a short photoperiod resulted in earlier flower initiation and differentiation, but shorter stems and smaller heads. Total Soluble Solids (TSS) of the vegetative organs (lower, upper and involucral leaves) remained stable during vegetative growth, floral initiation and growth of the inflorescence. However, TSS of the inflorescence increased dramatically during its differentiation and growth, and decreased to the initial level when head maturation was completed. Pruning height (i.e. stump or bearer length) significantly affected the rate of the head maturation but did not change the course of the florogenesis.