Regulation of node number in day-neutral Nicotiana tabacum: A factor in plant size

Abstract

Employing genotypes of day-neutral tobacco that exhibit a wide range in the number of nodes produced, it has been established that node number, and plant size, in tobacco is regulated, in large part, by two endogenous signals and one developmental state, competence. All genotypes have the same level of a root signal that maintains a vegetative pattern during early growth. The number of nodes produced before the formation of the terminal flower, as well as plant size, is a function of the strength of the floral stimulus from the leaves and the competence of the terminal meristem to respond to the floral stimulus by initiating the terminal flower.