The formation of regular and predictable patterns during development of multicellular plants require that positional information be available to cells, which then differentiate accordingly. The mechanisms by which these patterns of discrete cell types are formed in response to position is a long -standing problem in developmental biology. A cell that reacts in a special way in consequence of its association with another must do so because it acquires "information" from that other cell. Such information must be carried through either chemical or physical signals. In plants the nature of these signals, their origin, and how they are transmitted are unknown. The overall goal of the experiments described in this proposal is to achieve a better understanding of the controls of gene expression which govern these complex interactions during plant cell differentiation. These experiments will continue to characterize the communication factors which convey positional information in plants.
