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Turkish Journal of Botany

Abstract

Plagiochasma appendiculatum, a desiccation-tolerant liverwort, offers a unique system for unraveling the biophysical dynamics of photosynthetic recovery upon rehydration. This study employed high-resolution chlorophyll a fluorescence (ChlF) kinetics to clarify the sequential reactivation of photosystem II (PSII) during the desiccation-to-rehydration transition. Upon desiccation, the OJIP transient collapsed into a linear trace, indicating complete photochemical arrest and inactivation of PSII reaction centers (RCs). Rehydration triggered a biphasic recovery, including an initial rapid phase (0–30 min) marked by sharp increases in F0 and Fm , indicative of PSII–LHCII supercomplex reassembly and thylakoid membrane restoration, followed by a stabilization phase (30–125 min) wherein energy fluxes gradually normalized. Key biophysical parameters such as absorption per cross-section, trapping energy per cross-section, electron transport per cross-section, and density of functional RCs per cross-section showed temporally coordinated upregulation. Quantum efficiencies of photosynthesis and electron transport surged early in the rehydration timeline, whereas the quantum yield of dissipation declined, reinforcing the transition to efficient energy utilization. Performance indices revealed a strong correlation with PSII reactivation and electron transport efficiency, serving as integrated proxies for the system’s resilience. Multivariate analyses corroborated the ChlF trends, distinguishing three physiological phases: photochemical quiescence, transition, and full recovery. In conclusion, P. appendiculatum exhibits rapid recovery of PSII activity upon rehydration, indicating that water acts as a trigger for reactivating previously dormant PSII centers. This suggests that desiccation induces a reversible inactivation rather than structural damage to PSII, enabling the thallus to resume efficient photochemistry within minutes of hydration. These results also highlight the feasibility of ChlF analysis as a potent tool for probing the real-time functionality of photosystems in resurrection plants.

Author ORCID Identifier

VINEET SONI: 0000-0001-8995-9848

UPMA BHATT: 0000-0002-4424-9989

YASHWANT SOMPURA: 0000-0001-7108-7607

DOI

10.55730/1300-008X.2907

Keywords

Bryophytes, desiccation, electron transport, photosynthesis, photosystem II

First Page

303

Last Page

317

Publisher

The Scientific and Technological Research Council of Türkiye (TÜBİTAK)

Creative Commons License

Creative Commons Attribution 4.0 International License
This work is licensed under a Creative Commons Attribution 4.0 International License.

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