Control of leaf morphogenesis by long- and short-distance signaling: Differentiation of leaves into sun or shade types and compensated cell enlargement

Abstract

The flattened, thin lamina of leaves captures sunlight for photosynthesis and facilitates gas exchange. Therefore, the size and shape of a leaf are fundamentally important features of its integrity and function. Progress in developmental studies has suggested that long- and short-distance signaling pathways are involved in leaf formation. In this chapter, we introduce these signaling pathways, both of which can control final leaf shape and structure: a long-distance signaling pathway that governs the differentiation of leaves into sun and shade types, and a short-distance signaling pathway that appears to be involved in an organ-wide system that integrates cell proliferation and cell enlargement. Although none of the molecules involved in these two pathways have been identified, plausible mechanisms of these pathways are discussed based on present data. © 2008 Springer-Verlag Berlin Heidelberg.