| Autor: |
Clapham, David H., Ekberg, Inger, Norell, Lennart, Vince-Prue, Daphne |
| Předmět: |
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| Zdroj: |
Biological Rhythm Research; Oct2001, Vol. 32 Issue 4, p479, 9p |
| Abstrakt: |
Romanian populations of Norway spruce are induced to set terminal budsby four inductive cycles of 8 h light/16 h darkness. To distinguish betweencircadian and hourglass timekeeping for the photoperiodic control of budset,seedlings were raised in continuous light at 300 μmol m[sup -2] s[sup -1] at 20°C for 10 weeks. They were then exposed to anextended night regime consisting of three cycles of 8 h light/40 h dark with4-h or 1-h nightbreaks (120 μmol m[sup -2] s[sup -1] )applied to groups of plants at intervals during the extended night. Followinga final cycle of 8 h light/16 h dark to maximize budset, the plants were transferredto continuous light. Budset was delayed when the night-break was applied closeto the critical nightlength (CNL) of 6–7 h or about 22–23 h laterin the extended night, consistent with circadian rather than hourglass timekeeping.Confidence intervals were calculated for the times to maximum effect of thenight-breaks. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
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