Abstract
The above ground part of a plant is composed of a unit called phytomer, which is derived from a population of indeterminate cells located at the shoot apical meristem (SAM). The balance between indeterminate and determinate cells and the differentiation of cells, which undergo organogenesis are regulated at SAM so that the entire plant structure is organized. We have analyzed the course of the first step of lateral organ formation at SAM in rice. It is known that the indeterminate cells at SAM express OSH1 gene, a member of KNOTTED type homeobox gene family in rice, whereas it is down-regulated at the determinate cells which will differentiate into lateral organs. Using anti-OSH1 antibody, we conducted immunohistochemical analysis to detect the domain where determinate cells exist in SAM during the course of a plastochron. In this presentation, we will discuss the mechanism of differentiation of determinate cells visualized by OSH1 down-regulation.
