Control of leaf size and shape

A distinct “middle domain” is necessary for blade outgrowth. No WOX = narrow leaves. KNOX1 factor correlates with leaf complexit, which contributes to indeterminacy. 1. KNOX-1 genes are repressed at the site of leaf primordium initiation. 2. Simple leaves KNOX-1, genes stay off or 2. Compound leaves KNOX-1 genes turn on again in developing leaf primordia, conferring prolonged organogenic activity on the leaf edges.