2. Materials and methods
2.1. Plant material
Snapdragon (Antirrhinum majus L.) cv. Yellow Butterfly was grown under natural day-length conditions in a greenhouse (15 C minimum and 25 C maximum temperature). Flower spikes in
which the most developed flower bud (3 cm in length) was expected to open the next day, were harvested in the morning and placed in tap water. They were immediately transported to a
laboratory and used for experiments within 1 h.