Abstract

Jatropha curcas L. produces seed oil that is viewed as having tremendous potential as an economical alternative for diesel fuel. Seed yield, the main factor determining jatropha oil production, is highly associated with flower development, especially with the number of female flowers. However, little was known regarding floral development in this species. Accordingly, studies were undertaken to develop more information on the developmental process of floral organs. The early floral development was divided into 12 phases. The present study illustrated that, the sex differentiation of male or female flowers  occurred in phase-VII; earlier phases presented unapparent structural differences. The male flowers always had unisexual tissues during floral development. In contrast, early development of female flowers presented bisexual tissues, with male sexual degradation occurring at the later developmental phases. There was significant location specificity with respect to the inflorescence of male and female flowers. Based on this, the present study combined the total number of female flowers, and divided the inflorescence into three types, which had significant differences in the number of female flowers; they likewise presented different probabilities of occurrence in terms of different growing seasons.

Key words: Biofuel, flower, inflorescence, Jatropha curcas, sex differentiation, scanning electron microscopy.