Fate Map of the Organizing Shoot Apex in Gossypium

Chimeral seedlings from a “semigametic” strain of cotton were used as the basis for a clonal analysis of events in the progressive organization of the nascent shoot apex. At the time the proembryo becomes a globular stage embryo with a distinct dermatogen, the surface of the embryo contains an eight‐celled compartment for each cotyledon, a two‐celled compartment for the first leaf, a one‐celled compartment for the second leaf, and a three‐celled compartment for the apical initials and all subsequent leaves and aerial structures. The developmental history of the first two leaves differs in a fundamental way from that of all the other leaves.