The diameter of the cavity also increased, mainly from day 0 to 5 of vase life. For example, at 20 cm below the floral head the cavity had a diameter of 2.2 mm on day 0 whilst on day 5 it had increased to 3.3 mm (Fig. 7A). On day 0 there was no cavity in the stem at 5 cm below the floral head. By day 5 a cavity had formed with a diameter of 2.5 mm. We plotted the size of the area between the