Changes of Photosynthetic Behaviors and Photoprotection during Cell Transformation and Astaxanthin Accumulation in Haematococcus pluvialis Grown Outdoors in Tubular Photobioreactors

Abstract

The cell transformation from green motile cells to non-motile cells and astaxanthin accumulation can be induced in the green alga Haematococcus pluvialis cultured outdoors. In the initial 3 d of incubation (cell transformation phase), light absorption and photosynthetic electron transport became more efficient. After five days of incubation (astaxanthin accumulation phase), the light absorption per active reaction center (ABS/RC) increased, but the efficiency of electron transport (ψo) and the quantum yield of electron transport (φEo) decreased with increased time, indicating that the capacity of photosynthetic energy utilization decreased significantly during astaxanthin accumulation, leading to an imbalance between photosynthetic light absorption and energy utilization. It would inevitably aggravate photoinhibition under high light, e.g., at midday. However, the level of photoinhibition in H. pluvialis decreased as the incubation time increased, which is reflected by the fact that Fv/Fm determined at midday decreased significantly in the initial 3 d of incubation, but was affected very little after seven days of incubation, compared with that determined at predawn. This might be because the non-photochemical quenching, plastid terminal oxidase, photosystem I cyclic electron transport, defensive enzymes and the accumulated astaxanthin can protect cells against photoinhibition.

Special issue in honour of Prof. Reto J. Strasser - Efficacy of botanical pesticide for rotifer extermination during the cultivation of Nannochloropsis oculata probed by chlorophyll a fluorescence transient

“…The enhanced K-step indicates increased damage to the PSII donor side (Yusuf et al 2010, Zhang et al 2017. The MAIP reflects the pool size of end electron acceptors (Yusuf et al 2010, Zhang and Liu 2016, Zhang et al 2017. In the present study, B. plicatilis contamination in N. oculata cultures led to overreduction of the PSII acceptor side after 4 d of incubation (Fig.…”

“…4A,B), but the ET0/RC decreased (Fig. 4C) when cultures were exposed to B. plicatilis, which indicates that the balance between photosynthetic light absorption and energy utilization was disturbed (Zhang et al 2011(Zhang et al , 2017 by the inhibition of activities of reaction centers and PSII donor side after 3 d of incubation (Fig. 3A,C) due to rotifer contamination in N. oculata cultures.…”

“…According to the JIP-test, the increase in VJ represents the momentary maximum accumulations of QA − , resulting in the overreduction of PSII acceptor side (Zhang et al 2011, Zhang andLiu 2016). The enhanced K-step indicates increased damage to the PSII donor side (Yusuf et al 2010, Zhang et al 2017. The MAIP reflects the pool size of end electron acceptors (Yusuf et al 2010, Zhang and Liu 2016, Zhang et al 2017.…”

Analysis of light absorption and photosynthetic activity by Isochrysis galbana under different light qualities

“…Each parameter of OJIP transient was calculated by using the following original data (Strasser, Srivatava, & Tsimilli‐Michael, 2000; Strasser, Tsimilli‐Michael, & Srivastava, 2004; Yusuf et al, 2010; Zhang, Su, Zhang, Gong, & Liu, 2017): (a) F o , the fluorescence intensity at 20 μs when all of the PSII reaction centres (RC) are open; (b) F m , the maximal fluorescence intensity at 300 ms, assuming that the excitation intensity is high enough to close all of the RCs of PSII; and (c) the fluorescence intensity at a time of 300 μs, 2 ms and 30 ms, abbreviated as F 300 μs , F J and F I respectively. The following parameters were then calculated: the trapping of excitation energy per active reaction centre, TR/RC = 4 · ( F 300 μs − F o )/( F J − F o ); the light absorption per active reaction centre, ABS/RC = 4 · ( F 300 μs − F o )/( F J − F o )/(1 − F o / F m ); the electron transport per active reaction centre, ET/RC = 4 · ( F 300 μs − F o ) · [1 − ( F J − F o )/( F m − F o )]/( F J − F o ); the dissipation per active reaction centre, DI/RC = ABS/RC − TR/RC ; and the maximal amplitude of fluorescence between 300 μs and 300 ms, A IP = ( F m − F o )/( F I − F o ).…”

Plastid terminal oxidases in Chlamydomonas: connections with astaxanthin and bio-hydrogen production

“…Additionally, an increasing pattern of PTOX transcripts leads to carotenoid accumulation during flower bud development in Liriodendron tulipifera [29]. In another green microalga, Haematococcus pluvialis, comparative lipidomic and transcriptomic analyses reveal a concerted action of multiple defensive systems against HL stress [30] and PTOX, together with PSI cyclic electron transport, defensive enzyme and the accumulated astaxanthin, can protect microalgal cells against photoinhibition [31].…”