DETERMINATE (<i>det</i>) MUTANT OF PISUM SATIVUM (LEGUMINOSAE: PAPILIONOIDEAE) EXHIBITS AN INDETERMINATE GROWTH PATTERN

Abstract

Inflorescence ontogeny and morphology of the det mutant of Pisum sativum L. were investigated using scanning electron microscopy. This mutation causes the production of a limited number of axillary flowers followed by the formation of an apparent terminal flower slightly offset from the vertical. Our study indicates that the apparent terminal flower arises from an axillary meristem. The terminal meristem senesces and differentiates hairs, forming a rudimentary stub in the same manner as axillary meristems of conventional ( Det ) and det plants. Thus the dramatic effect of the det gene on inflorescence architecture results from early apical arrest rather than conversion of the terminal meristem to a flower as implied by the symbol det. This mutant will be valuable in elucidating regulation of apical arrest.