ISHS Acta Horticulturae 109: III International Symposium on Flower Bulbs
INTERNODAL GROWTH OF THE TULIP DURING THE GREENHOUSE PHASE OF STANDARD FORCING |
| Authors: | A.A. De Hertogh, T. Breg |
| Abstract:
The greenhouse growth patterns of standard forced Bing Crosby and Paul Richter tulips were determined at 12 hour intervals, 0800 and 2000 hours. The total internodal growth patterns of both cultivars were sigmoid in nature. There was a lag of 2–3 days after the plants were placed in the greenhouse. The initiation of the grand growth period was reached on day 8 and 12 for Paul Richter and Bing Crosby, respectively. Both cultivars flowered on day 21 which coincided with the termination of the grand growth period. An analysis of each internode showed that internode 1 (lowermost) initiated its grand growth period first, followed by internode 2 and 3 + 4, and, finally, the uppermost internode. Growth of the last internode continued beyond the day of anthesis and it contributed most to overall plant height. Based on the 12 hour sampling period used, it was clear that the scapes did not grow continuously. Growth generally occurred for 12 to 36 hours, then ceased for 12–24 hours. Only internode 1 consistently grew more at night, 2000 to 0800 hours, than during the day, 0800 to 2000 hours. | |
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