| Autor: |
Myster, J., Ernstsen, A., Junttila, Moe, R. |
| Předmět: |
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| Zdroj: |
Journal of Plant Growth Regulation; 1997, Vol. 16 Issue 4, p189, 8p |
| Abstrakt: |
The effects of thermo- and photoperiodicity on elongation growth and on endogenous level of gibberellins (GAs) in Begonia x hiemalis during various phases of the day-night cycle have been studied. Plant tissue was harvested during the day and night cycle alter temperature and photoperiodic treatments and analyzed for endogenous GAs using combined gas chromatography and mass spectrometry. Elongation growth increased when the difference between day and night temperature (DIF = DT - NT) increased from a negative value (-9.0 and -4.5°C) to zero and with increasing photoperiod from 8 to 16 h. When applied to the youngest apical leal; gibberellins A[sub1], A[sub4], and A[sub9] increased the elongation of internodes and petioles. GA[sub4] had a stronger effect on elongation growth than GA[sub1] and GA[sub9]. In relative values, the effect of these GAs decreased when DIF increased from -9 to 0°C. The time of applying the GAs during a day and night cycle had no effect on the growth responses. In general, endogenous levels of GA[sub19] and GA[sub20] were higher under negative DIF compared with zero DIF. The level of endogenous GA[sub1] in short day (SD)-grown plants was higher under zero DIF than under negative DIF, but this relationship did not appear in long day (LD)-grown plants. The main effects of photoperiod seem to be a higher level of GA[sub19] and GA[sub1] at SD compared with LD, whereas GA[sub20] and GA[sub9] show the opposite response to photoperiod. No significant differences in endogenous level of GA[sub1], GA[sub9], GA[sub19], and... [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
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