Practical aspects of the measurements of non‐photochemical chlorophyll fluorescence quenching in green microalgae Chlamydomonas reinhardtii using Open FluorCam

Abstract

Methods of chlorophyll fluorescence measurements are widely used in the research on photosynthesis and ecophysiology of plants and algae. Among them, a very popular technique is pulse‐amplitude‐modulation (PAM) flourometry, which is simple to carry out, fast and non‐invasive. However, this method is also prone to generate artifacts if the experiments were not planned and executed properly. Application of this technique to algae brings additional complications, which need to be taken into consideration. Some of them are connected with sample preparation and setting of the protocols used, while another origin from the differences in the photosynthetic apparatus and regulation of photosynthesis in various algal groups when compared to vascular plants. In the present paper, some important practical aspects concerning PAM fluorometry measurements in the green microalga Chlamydomonas reinhardtii have been described, including the equipment settings and sample preparation. The impact of growth conditions, such as light, temperature and medium type on the induction of non‐photochemical quenching of chlorophyll fluorescence have been also tackled, as well as the question of state transitions occurring in darkness.

Enhancing C. reinhardtii growth and metabolite biosynthesis using organic dyes as spectral convertors

“…The higher chlorophyll content in the dye-irradiated cultures implied that the dyes facilitated the absorption and transfer of light energy via photosynthesis. These findings supported previous research that demonstrated the enhancement of photosynthetic pigments including chlorophyll, when microalgae were exposed to optimal light conditions (Nawrocki, et al, 2020;Nowicka, 2020).…”

“…were not yet acclimated to the light conditions (Nowicka, 2020;Meagher, et al, 2021;Herdean, et al, 2022). However, as the experiment progressed, the Y(NO) yield gradually decreased (> day 4), signifying that the fraction of unregulated energy dissipation played a role during photoacclimation (Yadav, et al, 2020).…”

“…Apart from capturing light, carotenoids also play a role in protecting the photosynthetic apparatus from photo-oxidative damage (NPQ) (Nawrocki, et al, 2020;Nowicka, 2020). The lower carotenoid content in the LR culture implied that C. reinhardtii grown under LR was subjected to lower light stress compared to those grown under LY and R8G (Fig.…”

Combined Effects of Allelopathic Polyphenols on Microcystis aeruginosa and Response of Different Chlorophyll Fluorescence Parameters

“…The excess light energy is eliminated by non-photochemical quenching to protect the normal progress of the photochemical reaction (Yong et al, 2018). Therefore, non-photochemical quenching parameters always increase to protect photosynthesis under mild stress or in the early stage of severe stress by quenching (e.g., pH-gradient build-up, LHC 2 phosphorylation and zeaxanthin formation) and recovery (such as a stressadapting D1 protein) mechanisms, but decrease with further damage (Cummings et al, 2018;Nowicka, 2019). Photochemical quenching parameters reflect the photochemical capacity of PSII in the light-adapted state and correspond to the steady-state fraction of oxidized PSII reaction centers (Zulfugarov et al, 2018).…”

Comparative Chlorophyll Fluorescence and Growth Responses of two <i>Amaranthus</i> Species to Increased N Supply Variability

“…The potential photochemical efficiency (Fv/Fo) was calculated as (Fm-Fo)/Fo, these parameters reflect the potential activity of the PSII [39]. The maximum quantum yield of PSII photochemistry in dark, QYmax = Fv/Fm, reflects the maximum efficiency to transform the light absorbed by PSII [40]. The effective quantum yield of PSII photochemistry in the light, Fv'/Fm' = (Fm'-Fo')/Fm', indicates the primary efficiency at which light absorbed by PSII is used for photochemistry, which is the PSII operating efficiency when all the PSII centers were open (primary quinone electron acceptor-Q A oxidized) [19].…”