Fig. 7

A model of cotton fiber cell initiation and elongation. Fiber cell differentiation (left): Cell cycle arrest occurs in a subset of epidermal cells that are differentiating into fiber cells (blue boxes marked by X). Fiber cell initiation (middle): Upregulation of putative ribosomal protein subunit genes induces ribosome biosynthesis in early fiber cells (red boxes marked by X). Fiber cell elongation (right): Increased ribosome activities may promote translation for fiber cell elongation (red elongated boxes). Developing ovules corresponding to developmental stages (from left, middle, to right) are shown above corresponding stages