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Phytochrome decay in seedlings under continuous incandescent light
1Laboratory of Plant Physiological Research, Agricultural University, Wageningen, The Netherlands.
Planta
|January 31, 2014
Summary
High intensity light slows phytochrome decay in Amaranthus seedlings by accumulating unstable intermediates. These intermediates, unlike Pfr, do not decay, affecting overall phytochrome kinetics.
Area of Science:
- Plant photobiology
- Biophysics of photoreceptor decay
Background:
- Phytochrome decay typically follows first-order kinetics.
- High intensity light can alter phytochrome behavior in Amaranthus seedlings.
Purpose of the Study:
- To investigate the deviation in phytochrome decay under high intensity incandescent light.
- To test the hypothesis that phytochrome intermediates cause this altered decay rate.
Main Methods:
- Utilized a quasi-continuous measuring spectrophotometer to detect phytochrome intermediates.
- Measured phytochrome decay and intermediate accumulation under varying light intensities.
- Compared Amaranthus seedlings with Pisum epicotyl hooks.
Main Results:
- Demonstrated accumulation of weakly absorbing phytochrome intermediates under high light.
- Observed that these intermediates increase with light intensity and form Pfr in darkness.
- Confirmed preferential phytochrome loss in low-light regions of a cuvette, supporting intermediate accumulation.
Conclusions:
- High levels of phytochrome intermediates under high intensity light cause slower decay rates in Amaranthus.
- These intermediates, though forming Pfr in darkness, do not decay themselves.
- The findings explain the observed deviations in phytochrome kinetics and highlight species-specific responses.
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