Absorption, fluorescence spectra of chlorophyll a (Chl-a) and all-trans-β-carotene (β-Car) mixing solution are investigated in different polarity and polarizability solvents. The carotenoids regulate the energy flow in photosynthesis by interaction with chlorophyll, leading to an observable reduction of Chl-a fluorescence. The fluorescence red shifts with the increasing solvent polarizability. ...

Hydrogen gas (H2) and carbon monoxide (CO) are involved in plant growth and developmental processes and may induce plant tolerance to several stresses. However, the independent roles and interaction effect of H2 and CO in adventitious root development under drought conditions have still not received the needed research attention. We hypothesize that there exists crosstalk between H2 and CO duri...

in order to study the effects of water deficit stress and foliar application of chitosan in safflower (carthamus tinctorius l.), a pot experiment was conducted in 2009. experimental design was a randomized complete block in factorial arrangement with three replications. experimental factors were water deficit levels (unstressed (control) and 70% available water depletion from soil (water defici...

Vertical profiles of the in situ quantum yield of fluorescence of chlorophyll a, ff, were derived with an algorithm from spectral underwater radiometer measurements. Select inherent optical properties were obtained from an initial radiance reflectance inversion that was optimized by comparing retrieved estimates of phytoplankton absorption with independent measurements. The comparison of chloro...

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 oth...

in order to quantify and simulate the response of lemon balm (melissa officinalis l.) plants to cadmium (cd) concentrations in the soil, a pot experiment was conducted using completely randomized design (crd) with three replicates during 2014. the treatment consisted of twelve cd concentrations from 0 to 300 mg kg-1 of cd in the soil which was mixed with the experimental soil before planting. l...

Chlorophyll fluorescence imaging is a powerful tool in obtaining physiological information on plant leaf in non-destructive and non-invasive ways. Effects of Basta, one of the most popular commercially available foliar application-type herbicides, on in situ kidney bean leaf was analyzed with a developed chlorophyll fluorescence imaging system. Immediately after the Basta treatment, CO2 assimil...

With the advent of dedicated greenhouse gas space-borne spectrometers sporting high resolution spectra in the O2 A-band spectral region (755–774 nm), the retrieval of chlorophyll fluorescence has become feasible on a global scale. If unaccounted for, however, fluorescence can indirectly perturb the greenhouse gas retrievals as it perturbs the oxygen absorption features. As atmospheric CO2 measu...

The investigation of contaminant impact on algae requires rapid and reliable cell collection and optical detection. The capability of alternative current (AC) dielectrophoresis (DEP) collection of whole cell arrays with combined fluorescence microscopy detection to follow the alterations of chlorophyll fluorescence during environmental contaminant exposure was explored. The application of an AC...

To determine the mechanism of carotenoid-sensitized non-photochemical quenching in cyanobacteria, the kinetics of blue-light-induced quenching and fluorescence spectra were studied in the wild type and mutants of Synechocystis sp. PCC 6803 grown with or without iron. The blue-light-induced quenching was observed in the wild type as well as in mutants lacking PS II or IsiA confirming that neithe...