ISHS Acta Horticulturae 751: IV International Symposium on Rose Research and Cultivation
WATER STRESS SIGNALS OF CUT ROSES DURING THE POSTHARVEST PROCESS |
| Authors: | L. Hendriks, S. Spinarova |
| Keywords: | acoustic emissions, cavitation, cut flowers, vase life, ultrasonic acoustic emission technique (UAE) |
| Abstract:
Observations of ultrasonic acoustic emissions (UAE) during the postharvest process are discussed in this paper as indicators of water stress intensity of cut roses. Experiments with ‘First Red’ and ‘Prophyta’ roses showed that the highest rates of emissions occur in the peduncle zone, the lowest in the basal part of stems. Under adequate vase life conditions the first UAE signals appeared after about 2 days and showed a pronounced light and dark rhythm. Roses without this rhythm often had a reduced vase life, probably due to limited stomata control. The highest emission rates often were observed in the early morning, with a decrease until noon and a slight increase again in the afternoon. It is assumed that diurnal rhythm of stomata and refilling processes of cavitated vessels are responsible for this pattern. The emissions rate did not increase systematically during the postharvest process although the water potential of flower stems gradually decreased. Therefore, the emission rate can not be directly correlated to the water stress intensity. In the late stage of vase life, with shrinking symptoms at flower stems, signal rate increased considerably, obviously induced by fracture processes of fibres and not by cavitation events. | |
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