Abstract
Leaf meristem is a cell proliferative zone present in the lateral organ primordia, and it contributes to the expansion of lateral organ lamina. In this study, we investigated how the proliferative zone affects the final morphology of the lateral organs. We examined how cell proliferative zones differ in the primordia of polar –auxin transport inhibitor (PATI)-treated leaves and floral organs from normal foliage leaf primordia of Arabidopsis thaliana with focus on the spatial accumulation pattern of mRNA and protein of ANGUSTIFOLIA3 (AN3), a key element for leaf meristem positioning. As a result, we revealed that organ shape change by PATI treatment could not be attributed to changes in leaf-meristem positioning, size of the leaf meristem, or the expression pattern of AN3. Instead, it was attributed to altered cell division angles in the leaf meristem. In contrast, different shapes between sepals and petals compared with foliage leaves were observed to be correlated with both altered meristem position associated with altered AN3 expression patterns and different distributions of cell division angles. These results strongly indicate that lateral organ shapes are regulated via two aspects: position of meristem and cell division angles; the former is mainly governed by the AN3 expression pattern.
Competing Interest Statement
The authors have declared no competing interest.