ABSTRACT
This chapter focuses on the effects of assimilate supply and source–sink relationship on the development of the rose flower buds. A number of studies have shown that the young developing flower bud is a major sink for assimilates under favorable growing conditions, when the metabolites essential for its growth are in ample supply. The movement of assimilates produced by young and mature leaves to various parts of the plant was studied by pulsing leaves with 14CO2 and following the distribution of the labeled products. The light reaction that promotes the sink activity of the flower bud has some characteristics of the high irradiance reaction of photomorphogenesis. The import of assimilates into the developing flower bud may be regulated by the level of endogenous growth substances in the flower. Under adverse conditions, such as low light intensity or low temperature, both of which promote flower abortion, a decline in the levels of gibberellinlike substances was observed in rose shoots.
