ISHS Acta Horticulturae 378: Workshop on Environmental Regulation of Plant Morphogenesis
DIFFERENTIAL EFFECTS OF DIFFERENT DIF TREATMENTS ON CHRYSANTHEMUM AND POINSETTIA |
| Authors: | K.E. Cockshull, F.A. Langton, C. R.J. Cave |
| Abstract:
Poinsettia and chrysanthemum responded similarly to either positive or negative DIF treatments when the temperature difference was 4°C, but not when the difference was as large as -12°C. A six-hour drop in day temperature reduced shoot length of both species: treatment was more effective when given at the start rather than at the end of the day and the effectiveness of treatment increased with increasing magnitude of temperature drop. A three-hour drop in day temperature was not as effective as a six-hour drop and was most effective when given at the start of the day with poinsettia and when given three hours later with chrysanthemum. After treatment, the plants were allowed to flower in a common environment, by which time some of the initial effects on shoot length had been modified. The effects on stem extension were more likely to persist with poinsettia than chrysanthemum, but were also apparently modified by the differing effects of treatment on flowering in these two species. | |
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