Response of short-term heat shock on photosynthetic activity of soil crust cyanobacteria
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Updated: Jan 21, 2026

Standardized Methods for Measuring Induction of the Heat Shock Response in Caenorhabditis elegans
Published on: July 3, 2020
Jana Kvíderová1,2, Dhanesh Kumar3,4,5
1Centre for Polar Ecology, Faculty of Science, University of South Bohemia in České Budějovice, Na Zlatéstoce 3, České Budějovice, Czech Republic.
Abstract:
Short-term heat exposure in tropical regions can generate severe stress in the photosynthetic activity of soil crust cyanobacteria. We investigated the responses of two filamentous cyanobacteria, Scytonema tolypothrichoides and Tolypothrix bouteillei, to 1hr exposure at 35, 45, and 55 °C using variable chlorophyll fluorescence. Protocols for maximum quantum yield (FV/FM) and dark recovery of chlorophyll a fluorescence (OJIP) transient were applied. Heat exposure caused damage to the donor side of PSII, indicated by a decrease in FV/FM and a rapid increase in F0. After heat stress, photochemical energy utilization (φPo, φETo, and φRE1o) declined and energy dissipation (φDIo) increased. At 45 °C, the photosynthetic apparatus was reversibly damaged, since full recovery was observed after 7 days of relaxation. S. tolypothrichoides was more resistant to heat stress than T. bouteillei, confirming better adaptation to higher temperatures as observed in growth experiments.
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