Leaves within a canopy are exposed to a spatially and temporally fluctuating light environment which may cause lateral gradients in leaf internal CO(2) concentration and diffusion between shaded and illuminated areas. In previous studies it was hypothesized that lateral CO(2) diffusion may support leaf photosynthesis, but the magnitude of this effect is still not well understood. In the present...

salinity is one of major stresses which can severely limit plant production, especially in the arid and semi-arid regions. the present study was carried out to evaluate the impact of salinity stress on some physio-biochemical parameters in nitre bush plants (nitraria schoberi). thus, an experiment was carried out under natural conditions and salinity stress was induced by a combination of diffe...

Chlorophyll-a was regarded as the important indicator to describe the marine primary production because the chlorophyll a content of phytoplankton in the ocean is related to its photosynthesis production.The concentration of chlorophyll a is also the major parameter to evaluate marine water quality, organic pollution and detect the fishing ground, and the temporal and spatial variation of chlor...

Chlorophyll-a fluorescence analysis provides relevant information about the physiology of plants growing under abiotic stress. In this study, we evaluated the influence of cold stress on the photosynthetic machinery of transgenic turfgrass, Zoysia japonica, expressing oat phytochrome A (PhyA) or a hyperactive mutant phytochrome A (S599A) with post-translational phosphorylation blocked. Biochemi...

The mangrove habitat exhibits many unique physical features, one of the most important of which is a salinity gradient. Photosynthetic rates, as measured by leaf stomatal conductance and leaf chlorophyll fluorescence induction, were tested as indicators of salinity stress in seedlings of the red mangrove, Rhizophora mangle, grown under five different salinity levels: 0, 15, 30, 45, and 60 parts...

The effects of copper toxicity on the photosynthetic activities of Avicennia germinans was investigated using two CuSO4 concentrations (0.062 and 0.33 M) added in Hoagland's solution in an aerated hydroponic system. Photosynthesis and chlorophyll fluorescence were measured after 30 h of copper stress. Results obtained in this study show that increasing levels of Cu(+2) of 0.062 and 0.33 M Cu(+2...

Sun-induced canopy chlorophyll fluorescence in both the red (FR) and far-red (FFR) regions was estimated across a range of temporal scales and a range of species from different plant functional types using high resolution radiance spectra collected on the ground. Field measurements were collected with a state-of-the-art spectrometer setup and standardized methodology. Results showed that differ...

It has long been known that quinones quench chlorophyll fluorescence. This study reports the parameters of the fluorescence quenching of chlorophyll a by 1,4-benzoquinone, in ethanol, using the nonlinear analysis. The fluorescence intensity was measured at 670 nm for the blue and red excitation wavelengths: 430 nm and 650 nm, respectively. The quinone concentration in the samples ranged from 3....

The aggregation dependent correlation between fluorescence quenching and the electronic carotenoid– chlorophyll interactions, / S1 Chl Coupling , as measured by comparing chlorophyll fluorescence observed after twoand one-photon excitation, has been investigated using native LHC II samples as well as mutants lacking Chl 2 and Chl 13. For native LHC II the same linear correlation between / S1 Ch...

The first seagoing test of a prototype laser/fiber-optic system for in situ detection of ocean chlorophyll fluorescence is described. Radiation at 488 nm originating from a shipboard argon laser was transmitted through 20 of 200-microm core optical fiber to the distal tip mounted on the microstructure profiler, the Rapid Sampling Vertical Profiler. The backscattered fluorescence emission signal...