scholarly journals Do all chlorophyll fluorescence emission wavelengths capture the spring recovery of photosynthesis in boreal evergreen foliage?

2019 ◽  
Vol 42 (12) ◽  
pp. 3264-3279
Author(s):  
Chao Zhang ◽  
Jon Atherton ◽  
Josep Peñuelas ◽  
Iolanda Filella ◽  
Pasi Kolari ◽  
...  
Keyword(s):  
Chlorophyll Fluorescence ◽  
Fluorescence Emission

Temperature – Jump Chlorophyll Fluorescence Induction in Plants

1975 ◽  
Vol 30 (9-10) ◽  
pp. 689-690 ◽  
Author(s):  
Ulrich Schreiber ◽  
Konrad Colbow ◽  
William Vidaver
Keyword(s):  
Chlorophyll Fluorescence ◽  
Temperature Jump ◽  
Fluorescence Emission ◽  
Membrane Lipid ◽  
Fluorescence Induction ◽  
Chlorophyll Fluorescence Induction ◽  
Lipid Phase ◽  
Hydrogenase Activity ◽  
Heating Rates ◽  
Lipid Phase Transitions

In contrast to slower heating rates, a temperature jump reveals complex rise phases in the heat induced chlorophyll fluorescence emission increase in intact plants. Three rise phases have been detected which indicate the stepwise loss of different quenching mechanism of system II fluorescence. Two of the phases appear to reflect heat deactivation of the system II reaction centers, while the other may be associated with the induction of hydrogenase activity. Variations in Tmax of the jump, for the increase in different plant varieties, suggest a correlation with membrane lipid phase transitions affecting thylakoid membrane structure and the fluorescence increase.

scholarly journals Wide discrepancies in the magnitude and direction of modeled solar-induced chlorophyll fluorescence in response to light conditions

2020 ◽  
Vol 17 (13) ◽  
pp. 3733-3755 ◽  
Author(s):  
Nicholas C. Parazoo ◽  
Troy Magney ◽  
Alex Norton ◽  
Brett Raczka ◽  
Cédric Bacour ◽  
...  
Keyword(s):  
Chlorophyll Fluorescence ◽  
Canopy Structure ◽  
Fluorescence Emission ◽  
Light Response ◽  
Global Scale ◽  
Primary Objective ◽  
Mechanistic Modeling ◽  
Quantum Yields ◽  
Fluorescence Quantum Yields ◽  
Community Land Model

Abstract. Recent successes in passive remote sensing of far-red solar-induced chlorophyll fluorescence (SIF) have spurred the development and integration of canopy-level fluorescence models in global terrestrial biosphere models (TBMs) for climate and carbon cycle research. The interaction of fluorescence with photochemistry at the leaf and canopy scales provides opportunities to diagnose and constrain model simulations of photosynthesis and related processes, through direct comparison to and assimilation of tower, airborne, and satellite data. TBMs describe key processes related to the absorption of sunlight, leaf-level fluorescence emission, scattering, and reabsorption throughout the canopy. Here, we analyze simulations from an ensemble of process-based TBM–SIF models (SiB3 – Simple Biosphere Model, SiB4, CLM4.5 – Community Land Model, CLM5.0, BETHY – Biosphere Energy Transfer Hydrology, ORCHIDEE – Organizing Carbon and Hydrology In Dynamic Ecosystems, and BEPS – Boreal Ecosystems Productivity Simulator) and the SCOPE (Soil Canopy Observation Photosynthesis Energy) canopy radiation and vegetation model at a subalpine evergreen needleleaf forest near Niwot Ridge, Colorado. These models are forced with local meteorology and analyzed against tower-based continuous far-red SIF and gross-primary-productivity-partitioned (GPP) eddy covariance data at diurnal and synoptic scales during the growing season (July–August 2017). Our primary objective is to summarize the site-level state of the art in TBM–SIF modeling over a relatively short time period (summer) when light, canopy structure, and pigments are similar, setting the stage for regional- to global-scale analyses. We find that these models are generally well constrained in simulating photosynthetic yield but show strongly divergent patterns in the simulation of absorbed photosynthetic active radiation (PAR), absolute GPP and fluorescence, quantum yields, and light response at the leaf and canopy scales. This study highlights the need for mechanistic modeling of nonphotochemical quenching in stressed and unstressed environments and improved the representation of light absorption (APAR), distribution of light across sunlit and shaded leaves, and radiative transfer from the leaf to the canopy scale.

Water relations, chlorophyll fluorescence, and membrane permeability during desiccation in bryophytes from xeric, mesic, and hydric environments

1998 ◽  
Vol 76 (11) ◽  
pp. 1923-1929 ◽  
Author(s):  
Vicente I Deltoro ◽  
Angeles Calatayud ◽  
Cristina Gimeno ◽  
Eva Barreno
Keyword(s):  
Chlorophyll Fluorescence ◽  
Energy Dissipation ◽  
Water Content ◽  
Thermal Energy ◽  
Membrane Damage ◽  
Photosynthetic Apparatus ◽  
Fluorescence Emission ◽  
Conocephalum Conicum ◽  
Thermal Energy Dissipation ◽  
Fluorescence Characteristics

The interactions among water content, chlorophyll a fluorescence emission, and potassium leakage were analyzed during dehydration in desiccation-tolerant bryophytes from xeric habitats (Hedwigia ciliata (Hedw.) P. Beauv., Hypnum cupressiforme Hedw., Leucodon sciuroides (Hedw.) Schwaegr., Orthotrichum cupulatum Brid., Pleurochaete squarrosa (Brid.) Lindb., Porella platyphylla (L.) Pfeiff., and Tortula ruralis (Hedw.) Gaertn., Meyer & Scherb.) and desiccation-intolerant bryophytes from mesic and hydric environments (Barbula ehrenbergii (Lor.) Fleisch., Cinclidotus aquaticus (Hedw.) B. & S., Conocephalum conicum (L.) Underw., Lunularia cruciata (L.) Dum. ex Lindb., Palustriella commutata (Hedw.) Ochyra, Philonotis calcarea (B. & S.) Schimp., and Rhynchostegium riparioides (Hedw.) Card.). Their fluorescence characteristics at low water content were low efficiency of photosynthetic quantum conversion, closed photosystem II reaction centers, and strong nonphotochemical quenching only in desiccation-tolerant species. Full restoration of fluorescence parameters upon rewatering in species from xeric environments indicated that the photosynthetic apparatus was fully functional after desiccation. Species from hydric and mesic habitats were unable to restore photochemical activity. This might be a consequence of photoinhibition but also of membrane damage, as indicated by the large leakage of potassium. It is suggested that the capacity to enhance thermal energy dissipation during dehydration might have evolved in species from xeric environments as an adaptation to the utilization of an erratic supply of water. This protective strategy would lower the probability of photodamage during water loss and thus maintain the photosynthetic apparatus in a quickly recuperable state.Key words: bryophytes, chlorophyll fluorescence, dehydration, desiccation tolerance, thermal energy dissipation.

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