ISHS Acta Horticulturae 181: III International Symposium on Postharvest Physiology of Ornamentals
CONTROL OF PETAL EXPANSION DURING DIURNAL OPENING OF ROSES |
| Authors: | R. Y. Evans, M. S. Reid |
| Abstract:
Time-lapse cinematography was used to examine the opening of cut rose flowers. Flowers opened in a rhythmic fashion, starting before dawn and continuing rapidly for about 5 hours. No further opening then occurred until the following dawn. This rhythmic opening appears to be controlled by the day/night rhythm - it could be abolished by placing flowers in continuous light or dark. The daily pulses of flower opening were associated with increased flower diameter, fresh weight, dry weight and petal surface area. Petal growth occurs sequentially, beginning in the outermost whorl of petals and proceeding to the inner whorls. Petal expansion appears to be due to a pulsed increase in concentrations of soluble sugars in the petal cells, presumably from hydrolysis of petals starch. The starch content of the the outermost whorl declined substantially shortly before the onset of petal expansion, whereas the starch content of inner whorls remained constant during this time. | |
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