“COMPETITION FOR CARBOHYDRATES has been reported between petals of one flower, and among the opening flowers and flower buds. In cut Madelon roses, removal of the outer petals directly after harvest resulted in an increase in the surface area and in the sugar content of the innermost petals once they had fully developed. Competition between buds follows from standard horticultural practice, where flower buds are removed in order to produce larger sized single flowers.”
http://jxb.oxfordjournals.org/content/54/389/1801.full