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Presence of state transitions in the cryptophyte alga Guillardia theta.

Cheregi O, Kotabová E, Prášil O, Schröder WP, Kaňa R, Funk C - J. Exp. Bot. (2015)

Bottom Line: These state transitions were triggered by blue light absorbed by the membrane integrated chlorophyll a/c antennae, and green light absorbed by the lumenal biliproteins was ineffective.It is proposed that state transitions in G. theta are induced by small re-arrangements of the intrinsic antennae proteins, resulting in their coupling/uncoupling to the photosystems in state 1 or state 2, respectively.G. theta therefore represents a chromalveolate algae able to perform state transitions.

View Article: PubMed Central - PubMed

Affiliation: Department of Chemistry, Umeå University, SE-90187 Umeå, Sweden.

No MeSH data available.


Photosynthetic parameters of G. theta cultures grown under standard conditions. (A) The maximal efficiency of PSII photochemistry (Fv/Fm). (B) Electron transport rate (ETR) within Photosystem II. C. CO2 fixation rate measured as Pmax.
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Figure 8: Photosynthetic parameters of G. theta cultures grown under standard conditions. (A) The maximal efficiency of PSII photochemistry (Fv/Fm). (B) Electron transport rate (ETR) within Photosystem II. C. CO2 fixation rate measured as Pmax.

Mentions: Growth phase-dependent photosynthetic activity of primary (PSII efficiency, electron transport rate) and secondary (CO2 fixation) photosynthetic reactions was analysed in G. theta cultures. During lag and logarithmic growth phases, maximal efficiency of PSII photochemistry (Fv/Fm) was detected (Fig. 8). It then gradually declined as the culture progressed to the stationary phase (Day 6–9, Fig. 1). Fv/Fm decreased by 30% from its value of 0.7 during logarithmic phase (up to Day 6) to 0.5 in stationary phase (day 13) (Fig. 8A). The absolute electron transport rate (ETR), quantifying the maximal rate of electron generation in PSII and thus the maximal capacity of primary photosynthetic reactions rapidly declined between Days 6 and 9, when the cultures were entering the stationary phase (Fig. 8B). Within the stationary phase (Days 9–13) an additional small gradual decline of ETR was observed. Changes in ETR correlated with the overall capacity of photosynthetic carbon fixation measured from 14C incorporation rate (Fig. 8C). As expected, carbon fixation rapidly declined between Days 6 and 9, consistent with the lowered PSII maximal efficiency (Fig. 8A) and electron transport rate (Fig. 8B). The transition from logarithmic to stationary phase was therefore accompanied by pronounced changes in the overall photosynthetic capacity.


Presence of state transitions in the cryptophyte alga Guillardia theta.

Cheregi O, Kotabová E, Prášil O, Schröder WP, Kaňa R, Funk C - J. Exp. Bot. (2015)

Photosynthetic parameters of G. theta cultures grown under standard conditions. (A) The maximal efficiency of PSII photochemistry (Fv/Fm). (B) Electron transport rate (ETR) within Photosystem II. C. CO2 fixation rate measured as Pmax.
© Copyright Policy - creative-commons
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4588893&req=5

Figure 8: Photosynthetic parameters of G. theta cultures grown under standard conditions. (A) The maximal efficiency of PSII photochemistry (Fv/Fm). (B) Electron transport rate (ETR) within Photosystem II. C. CO2 fixation rate measured as Pmax.
Mentions: Growth phase-dependent photosynthetic activity of primary (PSII efficiency, electron transport rate) and secondary (CO2 fixation) photosynthetic reactions was analysed in G. theta cultures. During lag and logarithmic growth phases, maximal efficiency of PSII photochemistry (Fv/Fm) was detected (Fig. 8). It then gradually declined as the culture progressed to the stationary phase (Day 6–9, Fig. 1). Fv/Fm decreased by 30% from its value of 0.7 during logarithmic phase (up to Day 6) to 0.5 in stationary phase (day 13) (Fig. 8A). The absolute electron transport rate (ETR), quantifying the maximal rate of electron generation in PSII and thus the maximal capacity of primary photosynthetic reactions rapidly declined between Days 6 and 9, when the cultures were entering the stationary phase (Fig. 8B). Within the stationary phase (Days 9–13) an additional small gradual decline of ETR was observed. Changes in ETR correlated with the overall capacity of photosynthetic carbon fixation measured from 14C incorporation rate (Fig. 8C). As expected, carbon fixation rapidly declined between Days 6 and 9, consistent with the lowered PSII maximal efficiency (Fig. 8A) and electron transport rate (Fig. 8B). The transition from logarithmic to stationary phase was therefore accompanied by pronounced changes in the overall photosynthetic capacity.

Bottom Line: These state transitions were triggered by blue light absorbed by the membrane integrated chlorophyll a/c antennae, and green light absorbed by the lumenal biliproteins was ineffective.It is proposed that state transitions in G. theta are induced by small re-arrangements of the intrinsic antennae proteins, resulting in their coupling/uncoupling to the photosystems in state 1 or state 2, respectively.G. theta therefore represents a chromalveolate algae able to perform state transitions.

View Article: PubMed Central - PubMed

Affiliation: Department of Chemistry, Umeå University, SE-90187 Umeå, Sweden.

No MeSH data available.