Individual peduncle segments (5 cm) were excised from BPP
and control stems, immediately under the rose bud at stage 2 and
at colour break. In the case of bent peduncles, the 5 cm segments
included the bending site. For the bent peduncles, each sample
taken for the analysis comprised the lower or upper side of two
peduncles from the same developmental stage. For the straight peduncles, the sample for analysis comprised one longitudinal half
of each of two peduncle segments. Endogenous IAA in the peduncle
samples was extracted, purified [23] and quantified by radioimmunoassay
[24]. Each measurement was repeated for five
independent samples.