Abstract
Recent molecular developmental analyses of compound-leafed species have successfully uncovered several important aspects of compound leaf development such as regulatory mechanisms of complexity and essential factors for compound leaf development. On the other hand, spatiotemporal regulation of leaflet initiation has been largely unexplored. In some species leaflets arise acropetally, while in other species they arise basipetally. One hypothesis for the determining factor is growth rate gradient of leaf primordia along proximodistal axis. However, this idea has not yet been examined. Thus, we first examined the hypothesis by time course observation of leaf primordia development. We found that in California poppy of acropetal type, growth rate was correlated with the leaflet patterning, while it was not in potato of basipetal type. Based on the observation, we further hypothesized that other factors such as tissue competency could be important factors for leaflet initiation, and examined the possibility by histological and gene expression analyses. Moreover, we established laser ablation system to obtain clues of patterning mechanisms among leaflets.
