Fig. 7

Model explaining early rpk1-7 defects. a The failure to achieve sufficient RPK1 function (red arrowheads) by redundant genes in the rpk1-7 mutant is stochastic with respect to time and space. Early alterations have more severe effects than late ones on SAM- vs. cotyledon organizing cell groups. b Given are possible expression patterns (blue) of KNAT2 p :GUS as an example for a SAM-related gene. c The realization and maintenance of a shoot meristem depends on the precisely localized and concerted expression of all required SAM genes. d Shown are the frequencies of mono- and dicots with and without SAMs/eSMs based mainly on rpk1-7 data (for details see text and Methods). Green spots symbolize auxin maxima. Note that repeated PIN1 polarity and cell division disturbance can cause additional maxima and lobed cotyledons (see [22])