Planta

, Volume 228, Issue 4, pp 573–587

The long-term response to fluctuating light quality is an important and distinct light acclimation mechanism that supports survival of Arabidopsis thaliana under low light conditions

Authors

  • Raik Wagner
    • Junior Research Group, Institute for General Botany and Plant PhysiologyFriedrich-Schiller-University Jena
  • Lars Dietzel
    • Junior Research Group, Institute for General Botany and Plant PhysiologyFriedrich-Schiller-University Jena
  • Katharina Bräutigam
    • Junior Research Group, Institute for General Botany and Plant PhysiologyFriedrich-Schiller-University Jena
  • Wolfgang Fischer
    • Research Group Limnology, Institute for EcologyFriedrich-Schiller-University Jena
    • Junior Research Group, Institute for General Botany and Plant PhysiologyFriedrich-Schiller-University Jena
Original Article

DOI: 10.1007/s00425-008-0760-y

Cite this article as:
Wagner, R., Dietzel, L., Bräutigam, K. et al. Planta (2008) 228: 573. doi:10.1007/s00425-008-0760-y

Abstract

The long-term response (LTR) of higher plants to varying light qualities increases the photosynthetic yield; however, the benefit of this improvement for physiology and survival of plants is largely unknown, and its functional relation to other light acclimation responses has never been investigated. To unravel positive effects of the LTR we acclimated Arabidopsis thaliana for several days to light sources, which preferentially excite photosystem I (PSI) or photosystem II (PSII). After acclimation, plants revealed characteristic differences in chlorophyll fluorescence, thylakoid membrane stacking, phosphorylation state of PSII subunits and photosynthetic yield of PSII and PSI. These LTR-induced changes in the structure, function and efficiency of the photosynthetic machinery are true effects by light quality acclimation, which could not be induced by light intensity variations in the low light range. In addition, high light stress experiments indicated that the LTR is not involved in photoinhibition; however, it lowers non-photochemical quenching (NPQ) by directing more absorbed light energy into photochemical work. NPQ in turn is not essential for the LTR, since npq mutants performed a normal acclimation. We quantified the beneficial potential of the LTR by comparing wild-type plants with the LTR-deficient mutant stn7. The mutant exhibited a decreased effective quantum yield and produced only half of seeds when grown under fluctuating light quality conditions. Thus, the LTR represents a distinct acclimation response in addition to other already known responses that clearly improves plant physiology under low light conditions resulting in a pronounced positive effect on plant fitness.

Keywords

ArabidopsisLow light conditionLight qualityLong-term responsePhotosynthetic acclimationPlant fitness

Abbreviations

Chl

Chlorophyll

LHC

Light-harvesting complex

LTR

Long-term response

NPQ

Non-photochemical quenching

PS

Photosystem

PQ

Plastoquinone

WT

Wild-type

Supplementary material

425_2008_760_MOESM1_ESM.pdf (164 kb)
MOESM1 [Fig. S1 PAM measurements under PSII light with addition of PSI light. The fluorescence trace reveals the oxidising effect of the PSI light source. Plants grown under white light were subjected to the PSII light source (PAR: 24 μmol photons m-2 s-1) and supplemented with PSI light of 12 μmol photons m-2 s-1 for approx. 15 minutes. Then the PSI light source was turned off resulting in a rise of steady state fluorescence. Turning it on again after ca. 10 min, consequently, led to the contrary effect. The difference in the height of the initial rise of fluorescence and the drop of fluorescence at the end of the experiment can be ascribed to state transitions] (PDF 163 kb)
425_2008_760_MOESM2_ESM.pdf (2.7 mb)
MOESM2 [Fig. S2 Chl fluorescence kinetics of Arabidopsis thaliana WT using PSI- or PSII-light sources as actinic light. The schemes show typical Chl fluorescence traces obtained with PSI or PSII plants as shown in Fig. 2. In this experiments the intensity of the light sources was adjusted in such a way that it was either 20 µmol photons m-2 s-1 for PSI-light and 10 µmol photons m-2 s-1 for PSII-light or vice versa. The light source used for respective illumination of plants is indicated by an arrow below the traces. Upward arrow: light on; downward arrow: light off. Note the strong oxidizing effect of the PSI-light source which occurs regardless of its intensity as it becomes visible by the much lower steady state fluorescence in comparison to PSII-light. Full oxidation of the electron transport chain was achieved by intermittent illumination of the plants with a far-red light diode] (PDF 2774 kb)
425_2008_760_MOESM3_ESM.pdf (580 kb)
MOESM3 [Fig. S3 PSI activity determined by P700 absorbance changes. Typical far-red absorption curves of P700 from differentially acclimated plants are shown in relative absorption units. The growth light condition is indicated in the upper left corner of each diagramme. fr, actinic far-red light; sp, saturating white light pulse] (PDF 580 kb)

Copyright information

© Springer-Verlag 2008