Photochemical energy storage in isolated bundle sheath cells from Zea mays was examined. Photoacoustic spectroscopy was used in this study to monitor energy storage processes. The presence of methyl viologen or addition of substrates which activated carbon fixation, prevented energy storage processes through the electron transport system. The energy storage was inhibited completely by dibromoth...

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...

To identify genes associated with the cytokinin-induced enhanced drought tolerance, we analyzed the transcriptome of wild-type and transgenic tobacco (Nicotiana tabacum 'SR1') plants expressing P(SARK)::IPT (for senescence-associated receptor kinase::isopentenyltransferase) grown under well-watered and prolonged water deficit conditions using the tomato GeneChip. During water deficit, the expre...

The aim of this study was to explore the role of the mitochondrial alternative oxidase (AOX) in the protection of photosynthesis during drought in wheat leaves. The relative water contents of water-replete and drought-exposed wheat plants were 97.2+/-0.3 and 75+/-2, respectively. Drought increased the amount of leaf AOX protein and also enhanced the rate of AOX-dependent O(2) uptake by the resp...

Ocean acidification (OA) due to atmospheric CO2 rise is expected to influence marine primary productivity. In order to investigate the interactive effects of OA and light changes on diatoms, we grew Phaeodactylum tricornutum, under ambient (390 ppmv; LC) and elevated CO2 (1000 ppmv; HC) conditions for 80 generations, and measured its physiological performance under different light levels (60 µm...

A new imaging system capable of simultaneously measuring stomatal conductance and fluorescence parameters, non-photochemical quenching (NPQ) and photochemical yield of photosystem II (Phi(PSII)), in intact leaves under aerobic conditions by both thermal imaging and chlorophyll fluorescence imaging was developed. Changes in distributions of stomatal conductance and fluorescence parameters across...

Photo-physiological variability of in vivo chlorophyll fluorescence (CF) per unit of chlorophyll concentration (CC) is analyzed using a biophysical model to improve the accuracy of CC assessments. Field measurements of CF and photosystem II (PSII) photochemical yield (PY) with the Advanced Laser Fluorometer (ALF) in the Delaware and Chesapeake Bays are analyzed vs. high-performance liquid chrom...

To investigate how high light affects the responses of photosynthesis to heat stress, the effects of high temperature (25-42.5 degrees C) either in the dark or in the light (1000 micromol m(-2) s(-1)) on photosystem II (PSII) photochemistry and the xanthophyll cycle were investigated in rice plants. At temperatures higher than 35 degrees C, there was a decrease in the CO(2) assimilation rate, a...

The changes induced in the photosynthetic apparatus of spinach (Spinacia oleracea L.) seedlings exposed to iron deficiency shortly after germination were characterized with two proteomic approaches coupled with chlorophyll and xanthophyll analysis and in vivo measurements of photosynthesis. During the first 10 d of iron deficiency the concentrations of chlorophyll b and violaxanthin were greatl...

Photoautotrophic organisms efficiently regulate absorption of light energy to sustain photochemistry while promoting photoprotection. Photoprotection is achieved in part by triggering a series of dissipative processes termed non-photochemical quenching (NPQ), which depend on the re-organization of photosystem (PS) II supercomplexes in thylakoid membranes. Using atomic force microscopy, we chara...