Freezing temperature effects on photosystem II in Antarctic lichens evaluated by chlorophyll fluorescence.
J Plant Physiol
; 294: 154192, 2024 Mar.
Article
in En
| MEDLINE
| ID: mdl-38382176
ABSTRACT
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.
Key words
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Chlorophyll
/
Lichens
Language:
En
Journal:
J Plant Physiol
Journal subject:
BOTANICA
Year:
2024
Document type:
Article
Country of publication:
Germany