Freezing temperature effects on photosystem II in Antarctic lichens evaluated by chlorophyll fluorescence
- Author:
- Andrzejowska A., Hájek J., Puhovkin A., Harańczyk H. & Barták M.
- Year:
- 2024
- Journal:
- Journal of Plant Physiology
- Pages:
- 294: 154192 [10 p.]
- Url:
- https://doi.org/10.1016/j.jplph.2024.154192
This study explores and compares the limits for photosynthesis in subzero temperatures of six Antarctic lichens: Sphaerophorus globosus, Caloplaca regalis, Umbilicaria antarctica, Pseudephebe minuscula, Parmelia saxatilis and Lecania brialmontii combining linear cooling and chlorophyll fluorescence methods. The results revealed triphasic S-curves in the temperature response of the maximum quantum yield (FV/FM) and effective quantum yield of photosystem II (ΦPSII) for all species. All investigated species showed a high level of cryoresistance with critical temperatures (Tc) below −20 °C. However, record low Tc temperatures have been discovered for L. brialmotii (−54 °C for FV/FM and −40 °C for ΦPSII) and C. regalis (−52 °C for FV/FM and −38 °C for ΦPSII). Additionally, the yield differentials (FV/FM − ΦPSII) in functions of temperature revealed one or two peaks, with the larger one occurring for temperatures below −20 °C for the above-mentioned species. Finally, Kautsky kinetics were measured and compared at different temperatures (20 °C, 10 °C, 0 °C and −10 °C and then −10 °C after 1 h of incubation). This research serves as a foundation for further developing investigations into the biophysical mechanisms by which photosynthesis is carried out at subzero temperatures.
Keywords: Chlorophyll fluorescence ; Linear cooling ; Antarctic lichens ; Kautsky kinetic ; Freezing tolerance ; Photosynthesis.
- Id:
- 36517
- Submitter:
- zpalice
- Post_time:
- Monday, 03 June 2024 11:10