The theory that the origin of new leaf primordia at a stem apex is governed physically by the amount of space between existing primordia. It is postulated that a new primordium only arises at a point where a certain minimum amount of space has become available. This is usually between the penultimately formed primordium and the one formed previous to that. The pattern that results from such restrictions is the same as would occur if inhibitors were released by older primordia (see repulsion theory). See also phyllotaxis. |
