Within the developing ovule primordia, much is known about molecular patterning events along the proximal to distal axis and the mechanisms of integument development. Also dramatic progress has been made with respect to understanding the subsequent development of the female gametophyte within the maturing ovule. However, considerably less is known about the earliest steps in ovule development: the mechanisms of ovule initiation, and in the establishment and maintenance of the meristematic tissues of the carpel margin meristem that generate the ovule primordia. Gynoecial development in Arabidopsis initiates at stage 6 of floral development. The gynoecial primordium is first morphologically recognizable as a dome or mound of cells, oval in cross section, that forms from the cells of the central most portion of floral meristem. During stage 6 the different spatial domains of the gynoecial tube are already discernable based on the differential expression of genes within the medial portion of the gynoecium versus the lateral domains, as well as along the inner to outer axis. During floral stages 6 and 7 the proliferation of cells along the perimeter of the gynoecial dome leads to the formation of a tube-shaped structure. The single gynoecium primordium likely represents a composite of two congenitally-fused carpel organs in a phylogenetic sense. In this scenario, the medial portions of the gynoecium represent the fused margins of the two component carpels. The adaxial portions of the medial/marginal domain maintain meristematic potential throughout the elongation of the gynoecial tube and these regions have been termed carpel margin meristems. Each Arabidopsis gynoecium contains two CMMs that are positioned within the adaxial portions of the medial domain of the gynoecium. During floral stages 7 and 8 the CMM takes the shape of a ridge of tissue that extends along the apical basal extent of the gynoecial tube. During mid to late stage 8 each CMM gives rise to two rows of ovule primordia from the peripheral portions of the meristematic ridge. Later, the CMM also gives rise to the gynoecial septum and transmitting tract and likely generates portions of the stigmatic and stylar tissues. A variety of data CUDC-907 supply suggests that the proper specification of adaxial and medial/ marginal positional identities are important for the development of the CMM and subsequent ovule initiation. A number of genes have been suggested to play a role in the maintenance of meristematic potential in the CMM and for the subsequent initiation of ovule primordia from the flanks of the CMM. While no single mutant has been reported to strongly Tubulin Acetylation Inducer disrupt ovule initiation, several higher order mutant combinations have been reported to disrupt the initiation of ovule primordia from the CMM. The seuss aintegumenta double mutant is one such genetic mutant combination.