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Parallel measurements of CO2 assimilation, Chl fluorescence and 800 nm transmittance were carried out on intact leaves of wild type and cytochrome b6/f deficient transgenic tobacco grown at two different light intensities and temperatures, with the aim to diagnose processes limiting quantum yield of photosynthesis and investigate their adaptations to growth(More)
A computer model comprising light reactions, electron-proton transport, enzymatic reactions, and regulatory functions of C3 photosynthesis has been developed as a system of differential budget equations for intermediate compounds. The emphasis is on electron transport through PSII and PSI and on the modeling of Chl fluorescence and 810 nm absorptance(More)
The global modelling of photosynthesis is based on exact knowledge of the leaf photosynthetic machinery. The capacities of partial reactions of leaf photosynthesis develop at different rates, but it is not clear how the development of photoreactions and the Calvin cycle are co-ordinated. We investigated the development of foliar photosynthesis in the(More)
Finite mesophyll diffusion conductance (g(m) ) significantly constrains net assimilation rate (A(n) ), but g(m) variations and variation sources in response to environmental stresses during leaf development are imperfectly known. The combined effects of light and water limitations on g(m) and diffusion limitations of photosynthesis were studied in(More)
Oxygen evolution and Chl fluorescence induction were measured during multiple turnover light pulses (MTP) of 630-nm wavelength, intensities from 250 to 8,000 μmol quanta m−2 s−1 and duration from 0.3 to 200 ms in sunflower leaves at 22 °C. The ambient O2 concentration was 10–30 ppm and MTP were applied after pre-illumination under far-red light (FRL), which(More)
Fast cyclic electron transport (CET) around photosystem I (PS I) was observed in sunflower (Helianthus annuus L.) leaves under intense far-red light (FRL) of up to 200 mumol quanta m(-2) s(-1). The electron transport rate (ETR) through PS I was found from the FRL-dark transmittance change at 810 and 950 nm, which was deconvoluted into redox states and pool(More)
Measurements of 810 nm transmittance changes in leaves, simultaneously with Chl fluorescence, CO(2) uptake and O(2) evolution, were carried out on potato (Solanum tuberosum L.) leaves with altered expression of plastidic NADP-dependent malate dehydrogenase. Electron transport rates were calculated: J(C) from the CO(2) uptake rate considering(More)
Oscillations in the rate of photosynthesis of sunflower (Helianthus annuus L.) leaves were induced by subjecting leaves, whose photosynthetic apparatus had been activated, to a sudden transition from darkness or low light to high-intensity illumination, or by transfering them in the light from air to an atmosphere containing saturating CO2. It was found(More)
Light response (at 300 ppm CO(2) and 10-50 ppm O(2) in N(2)) and CO(2) response curves [at absorbed photon fluence rate (PAD) of 550 μmol m(-2) s(-1)] of O(2) evolution and CO(2) uptake were measured in tobacco (Nicotiana tabacum L.) leaves grown on either NO(3)(-) or NH(4)(+) as N source and in potato (Solanum tuberosum L.), sorghum (Sorghum bicolor L.(More)
This work addresses the question of occurrence and function of photosystem II (PSII) in bundle sheath (BS) cells of leaves possessing NADP-malic enzyme-type C4 photosynthesis (Zea mays). Although no requirement for PSII activity in the BS has been established, several component proteins of PSII have been detected in BS cells of developing maize leaves(More)