POLYPEPTIDE PROFILES FROM COTYLEDONS OF DEVELOPING AND PHOTOPERIODICALLY INDUCED SEEDLINGS OF THE JAPANESE MORNING GLORY (PHARBITIS (IPOMOEA) NIL)

An unknown substance(s) produced in the cotyledons of seedlings of the Japanese morning glory (Pharbitis nil) during a defined period of darkness triggers the subsequent initiation of floral buds at apical and axillary meristems. Recent studies have concentrated on characterizing molecular changes as a possible mechanism associated with its synthesis, but these have failed to eliminate interference due to lack of development unity in the sampled population and to consider different kinetic alternatives of those potential changes. The current study demonstrates that numerous age-related changes occur in polypeptides from cotyledons during growth under noninductive conditions, but that these are minimal in older seedlings selected for improved synchrony of the floral response. Polypeptides from older seedlings sampled at various times during and after a dark inductive period were examined by two-dimensional polyacrylamide gel electrophoresis (2-D PAGE). No differences associated with floral induction could be detected. The results indicate that changes in gene expression correlated with floral-induction do not occur in the abundant polypeptide fraction within the limitations of the techniques employed.