Blüten- und Fruchtbildung. — Flower and fruit formation

Abstract

Flower initiation marks the transition from vegetative to reproductive growth in seed plants. It is thus a crucial event in the life of these plants, particularly so because of the peculiar relation of vegetative and reproductive development in seed plants which is in turn an outcome of the morphological nature of the flower. Flowers are modified shoots which are produced by modified shoot meristems, the flower primordia. However, once a meristem has been determined as a flower primordium, it is usually unable --- except perhaps at the very earliest stages --- of reverting to vegetative growth. Vegetative growth and reproductive development in seed plants are thus in a certain sense mutually exclusive; as far as a particular meristem is concerned, flower initiation means the end of its life. The central problem of the physiology of flower initiation is to understand which factors cause a shoot meristem to become a flower primordium, and how they consummate their action.