2000, 2003b), whereas the inhibition of auxin transport has been shown to block organ formation and the establishment of the convergence In experimental manipulations, the application of auxin at the peripheral zone of the meristem is sufficient to induce This maximumДЄrises concomitantly with the subcellular localization of the auxin transport protein PIN1 toward the auxin convergence pointДЄt the center of the incipient primordium ( Reinhardt et al. 2006), an auxin maximum in the L1 surface layer of the meristem is the earliest marker of a new leaf primordium. Simulations confirmed that these mechanisms can produce the observed patterns, but until recently the lack of experimentalДata has made it hard to judge their biological plausibility.ДЄccording to current data ( Benkova et al. Theoretical approaches have suggested a variety of mechanisms for the regulation of phyllotaxisДЄnd vein formation ( Hellendoorn and Lindenmayer 1974 Green 1980 Mitchison 1980 Meinhardt 1982 Couder et al. Strand of vascular tissue in the center of the leaf primordium that is specified even before the primordium begins to bulge The process of leaf initiation is closely linked to the formation of the midvein, the Leaves (or flowers) are initiated at the shoot apical meristem, in a band of cells derived from the stemД¬ells at the summit of the meristem. Phyllotaxis, the regular arrangement of lateral organs around a plant stem, is an example of developmental pattern formationДЄnd organogenesis. Of the canalization hypothesis namely, how both high flux and high concentration can occur simultaneously in emerging veins. The initiation of the midvein is consistent with experimental observation and offers an explanation for a long-standing criticism In addition, the appearance of high auxin concentration in our simulations throughout The dynamics of observed PIN1 localization. Computer simulations of the resulting dual polarization model are able to reproduce PIN1 polarization operate simultaneously. Our detailed analysis of PIN1 polarization during midvein initiation suggests that both mechanisms for Intersect during the initiation of the midvein, which raises the question of how two different PIN1 polarization mechanisms The formation of vascular strands is thought to proceed by вЂњwith-the-fluxвЂќ PIN1 polarization. For leaf positioning (phyllotaxis), an вЂњup-the-gradientвЂќ PIN1 polarization mechanism has been proposed, whereas Two distinct molecular mechanisms for the subcellular polarization of PIN1 have been Meristem, auxin gradients are thought to be set up through a feedback loop between auxin and the activity and polar localization The plant hormone auxin mediates developmental patterning by a mechanism that is based on active transport.

Define leaf primordia