Fig. 1: Hydrogen production following light and dark fluctuations.
From: A PSII photosynthetic control is activated in anoxic cultures of green algae following illumination
Mixotrophic C. reinhardtii wild-type cultures (strain CC124) were incubated for an hour under dark anaerobiosis, after which they were challenged with light fluctuations of 2 min under illumination (at an irradiance of 370 µmol photons m−² s−¹, white background), followed by 3 min of darkness (gray background). Shown are the differences between the initial light exposure (dashed) and the average of the successive exposures (solid). H2 (a) and O2 (b) concentrations were measured using MIMS, and Chl a fluorescence was measured simultaneously using PAM (c). During illuminations, the cells were exposed to saturating pulses (marked with a red arrow), to assess maximal fluorescence intensity. The same protocol was used to assess changes in electrochromic shifts (at 520–546 nm) by a JTS (d), for which the cells were exposed to a laser flash of 30 s prior to each light exposure (see black arrows in panel a). The right graphs in each panel show a comparison between the initial (dashed) and the average of all three successive (solid) exposures, relative to their state at light onset, or laser flash (time, 0). Each curve represents the averaged result of at least 3 biological repetitions.
