TY - JOUR
T1 - Photoacclimation in Dunaliella tertiolecta reveals a unique NPQ pattern upon exposure to irradiance
AU - Ihnken, S.
AU - Kromkamp, J.C.
AU - Beardall, J.
N1 - Reporting year: 2011
Metis note: 5100; CEME; MM
PY - 2011
Y1 - 2011
N2 - Highly time-resolved photoacclimation patterns
of the chlorophyte microalga Dunaliella tertiolecta
during exposure to an off–on–off (block) light pattern of
saturating photon flux, and to a regime of consecutive
increasing light intensities are presented. Non-photochemical
quenching (NPQ) mechanisms unexpectedly
responded with an initial decrease during dark–light transitions.
NPQ values started to rise after light exposure of
approximately 4 min. State-transitions, measured as a
change of PSII:PSI fluorescence emission at 77 K, did not
contribute to early NPQ oscillations. Addition of the
uncoupler CCCP, however, caused a rapid increase in
fluorescence and showed the significance of qE for NPQ.
Partitioning of the quantum efficiencies showed that constitutive
NPQ was (a) higher than qE-driven NPQ and
(b) responded to light treatment within seconds, suggesting
an active role of constitutive NPQ in variable energy dissipation,
although it is thought to contribute statically to
NPQ. The PSII connectivity parameter p correlated well
with F0, Fm
0 and NPQ during the early phase of the dark–
light transients in sub-saturating light, suggesting a plastic
energy distribution pattern within energetically connected
PSII centres. In consecutive increasing photon flux experiments,
correlations were weaker during the second light
increment. Changes in connectivity can present an early
photoresponse that are reflected in fluorescence signals and
NPQ and might be responsive to the short-term acclimation
state, and/or to the actinic photon flux.
AB - Highly time-resolved photoacclimation patterns
of the chlorophyte microalga Dunaliella tertiolecta
during exposure to an off–on–off (block) light pattern of
saturating photon flux, and to a regime of consecutive
increasing light intensities are presented. Non-photochemical
quenching (NPQ) mechanisms unexpectedly
responded with an initial decrease during dark–light transitions.
NPQ values started to rise after light exposure of
approximately 4 min. State-transitions, measured as a
change of PSII:PSI fluorescence emission at 77 K, did not
contribute to early NPQ oscillations. Addition of the
uncoupler CCCP, however, caused a rapid increase in
fluorescence and showed the significance of qE for NPQ.
Partitioning of the quantum efficiencies showed that constitutive
NPQ was (a) higher than qE-driven NPQ and
(b) responded to light treatment within seconds, suggesting
an active role of constitutive NPQ in variable energy dissipation,
although it is thought to contribute statically to
NPQ. The PSII connectivity parameter p correlated well
with F0, Fm
0 and NPQ during the early phase of the dark–
light transients in sub-saturating light, suggesting a plastic
energy distribution pattern within energetically connected
PSII centres. In consecutive increasing photon flux experiments,
correlations were weaker during the second light
increment. Changes in connectivity can present an early
photoresponse that are reflected in fluorescence signals and
NPQ and might be responsive to the short-term acclimation
state, and/or to the actinic photon flux.
U2 - 10.1007/s11120-011-9709-2
DO - 10.1007/s11120-011-9709-2
M3 - Article
VL - 110
SP - 123
EP - 137
JO - Photosynthesis Research
JF - Photosynthesis Research
SN - 0166-8595
IS - 2
ER -