Cytokinin regulates the size and activity of the shoot apical meristem (SAM). A reduction of the cytokinin content or signaling reduces SAM size and activity while a higher cytokinin content enlarges SAM size. It is known that this cytokinin activity is realized at least in part through the WUS/CLV pathway. However, the spatial organization of cytokinin action is not well understood. Here, we report on experiments exploring the spatial organization of cytokinin activity by increasing or decreasing cytokinin signaling in distinct domains of the SAM. To this end, the constitutively active cytokinin receptor variant ROCK2, activating or silencing variants of the B-type response regulator ARR10, or a cytokinin-degrading CKX enzyme were ectopically expressed under control of the pFBD, pCLV1, pWUS and pCLV3 promoters in wild type as well as in arr mutants. The results show that enhanced cytokinin degradation in the CLV1 domain is sufficient to reduce SAM size, while ROCK2 expression in the stem cells retards the transition from cell division to differentiation, thus causing a drastic increase of SAM size. The altered cytokinin activity may change additional parameters of growth and development, such as rosette size, stem diameter, and the duration of flowering time. We will report on the ongoing analysis of transgenic lines with altered cytokinin status and their phenotypes.