Floral-specific polypeptides in Silene coeli-rosa

In Silene coeli-rosa (L.) Godron given a 7-long-day inductive treatment, scanning electron microscopy and two-dimensional minigel electrophoreses of total proteins were used to characterize the polypeptide pattern of each type of floral organ through early differentiation and to research the changes that occurred in the reproductive apex that initiated each new floral whorl. During early differentiation of each whorl, some polypeptides no longer expressed in the subsequent whorls were distinguished as unique to sepals (24), petals (7), and stamens (4). Newly expressed polypeptides were also observed that occasionally persisted in the subsequent whorl. However, qualitative changes were only between 1.2 and 3.8% of all the detected spots, and common spots remained the most numerous, even if a modulation of their expression in the various types of floral organs was observed. Comparison between leaves and differentiating floral organs showed that sepals shared 57% of their polypeptide spots with leaves, whereas petals, stamens, or carpels shared only 14.6, 10.5, and 7.7%, respectively. In the reproductive apex, polypeptides newly detected or unique to a particular whorl were expressed at the time of initiation of this whorl. However, some of these spots were also detected before, in the apex that initiated the preceding whorl, or they persisted later, in the apex that initiated the following whorl. Key words: floral organs, polypeptides, reproductive apex, Silene coeli-rosa.