ce has become one of the most powerful methods for assessing photosynthetic performance in plant physiological experiments (Horton and Bowyer, 1990; Krause and Weis, 1991). This has resulted almost entirely from the development of methods to distinguish photochemical and nonphotochemical quenching of fluorescence. Moreover, it is now clear that the process of nonphotochemical quenching itself i...

Exposure of plants to irradiances far above the light saturation point of photosynthesis, known as highlight stress, induces various responses including light adaptation of the photosynthetic apparatus and chloroplast ultrastructure by formation of sun-type chloroplasts. The latter possess a lower cross section for light absorption (less light-harvesting chlorophyll proteins) and higher rates o...

The effect of excess of cadmium (Cd) on chlorophyll fluorescence of barley seedlings was studied. The leaves were dark-adapted and then illuminated at 10 different light intensities within the range of 70–1600 μmol.m–2.s–1 photosynthetically active radiation (PAR). It was found that Cd decreases the chlorophyll fluorescence parameters in dark-adapted leaves: ground (Fo), maximal (Fm) and variab...

As freshwater becomes an increasingly scarce and expensive natural resource, novel water-saving irrigation methods for dwarfing apple orchards are needed in the Loess Plateau. However, studies lacking on effects of root-zone technology leaf-level photosynthesis, which directly determines yield survival ability trees. In this study, leaf gas characteristics water status five-year-old trees Plate...

As part of a program to select maritime pine (Pinus pinaster Ait.) genotypes for resistance to low winter temperatures, we examined variation in photosystem II activity by chlorophyll fluorescence. Populations and families within populations from contrasting climates were tested during two consecutive winters through two progeny trials, one located at a continental and xeric site and one at a m...

The measurement of carbon isotope discrimination (∆) provides an integrated insight into theresponse of plants to environmental change. To investigate the potential use of ∆ for identifyingshade tolerance in rice, five rice varieties were selected and artificially shaded (53% lightreduction) during the grain-filling period in 2010 and 2011, in Sichuan, China. Shadingtreatment had a significant ...

Nitric oxide (NO) is one of the key elements in the complex signalling pathway leading to stomatal closure by inducing reversible protein phosphorylation and Ca(2+) release from intracellular stores. As photosynthesis in guard cells also contributes to stomatal function, the aim of this study was to explore the potential role of NO as a photosynthetic regulator. This work provides the first des...

The chlorophyll fluorescence imaging technique is a valuable tool to study the impact of heavy metal stress in plants. The aim of this paper was to investigate the influence of Cd on photosynthetic apparatus of white cabbage (Brassica oleracea subsp. capitata f. alba) plants. Two cabbage cultivars ‘Ditmarska Najwcześniejsza’ (‘DN’; early) and ‘Amager Polana’ (‘AP’; late) were used. Cd was appli...

To reveal and quantify the interactive effects of drought stresses and elevated CO2 concentration [CO2] on photochemistry efficiency of cucumber seedlings, the portable chlorophyll meter was used to measure the chlorophyll content, and the Imaging-PAM was used to image the chlorophyll fluorescence parameters and rapid light response curves (RLC) of leaves in two adjacent greenhouses. The result...