CHARACTERIZATION OF DEVELOPMENT IN MAIZE THROUGH THE USE OF MUTANTS. I. THE POLYTYPIC (Pt) AND RAMOSA-1 (ra1) MUTANTS |
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Authors: | S N Postlethwait O E Nelson |
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Institution: | Department of Botany and Plant Pathology, Purdue University, Lafayette, Indiana |
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Abstract: | The origin of morphological differences attributable to mutant genes can be identified at certain switch points in the developmental pathway. The effect of the Polytypic (Pt) gene is a stimulus to meristems in the developing inflorescence to continuous initiation of differentiating structures. The most severe expression is a suppression of meristematic activity. The action of the gene is a superimposition of its effect on the normal developmental pathway. The ramosa-1 (ra1) gene interrupts the normal sequence of events, at the switch point, which would normally result in spikelet formation, and there is produced instead a lateral branch. The response of numerous switch points in the developmental pathway of the maize inflorescence supports the conclusion that meristems are a plastic system genetically programmed at successive intervals. |
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