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Review
. 2006 Apr;18(4):792-803.
doi: 10.1105/tpc.106.040980.

Plant circadian rhythms

C Robertson McClung  1
Affiliations
Review

Plant circadian rhythms

C Robertson McClung. Plant Cell. 2006 Apr.
No abstract available

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Figures

Figure 1.
Figure 1.
Critical Terms Used to Describe Circadian Rhythms. Period is defined as the time to complete one cycle. It is commonly measured from peak to peak but could equally be measured from trough to trough or from any specified phase marker. Phase is the time of day for any given event. For example, if the peak in a rhythm occurred at dawn, the phase of the peak would be defined as 0 h. If a rhythm peaked 6 h after dawn, its phase would be 6 h, and so on. Phase is often defined in zeitgeber time (ZT). Zeitgeber is German for time giver, and any stimulus that imparts time information to the clock is a zeitgeber. The onset of light is a powerful zeitgeber, and dawn is defined as ZT0. The amplitude of the rhythm is defined as one-half the peak-to-trough distance.
Figure 2.
Figure 2.
Leaf Movements of a Representative Species. (A) Sleep movements of Phaseolus coccineus. The position of the primary leaves of a seedling at night is at the left and during the day is at the right. (B) Circadian rhythm of leaf movements of P. coccineus entrained to light/dark cycles and monitored in continuous light. As can be inferred from the leaf positions in (A), the peaks of the curve represent the nighttime leaf position. The vertical lines indicate 24-h intervals. The period for this trace is ∼27 h. (A) was originally published as Figure 14 and (B) as Figure 4 in Chapter 2 in Bünning (1973). Both are reproduced with kind permission of Springer Science and Business Media.
Figure 3.
Figure 3.
A Molecular Model of the Arabidopsis thaliana Circadian Oscillator. Genes are indicated by solid boxes with the gene names indicated at the left. Proteins are indicated by oval and oblong shapes, with the protein name indicated within the shape. Transcription and translation are indicated by dashed lines. Protein activity is indicated with solid lines, with lines ending in arrowheads indicating positive action and lines ending in perpendicular dashes indicating negative action. The core CCA1/LHY/TOC1 feedback loop is highlighted in green with thick lines and closed shapes. Phosphorylation of LHY and CCA1 by CK2 is indicated with circled Ps. Shaded area indicates activities peaking in the subjective night, and white area indicates activities peaking during the subjective day.
See this image and copyright information in PMC

References

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