The ubiquity and importance of photosynthetic organisms in nature has made the molecular mechanisms of photosynthesis a widely studied subject at both structural and functional levels. A current challenge is to understand the supramolecular assembly of the proteins involved in photosynthesis in native membranes. We have used atomic force microscopy to study the architecture of the photosyntheti...

BACKGROUND AND AIMS Concomitant increases in O(2) and irradiance upon de-submergence can cause photoinhibition and photo-oxidative damage to the photosynthetic apparatus of plants. As energy and carbohydrate supply from photosynthesis is needed for growth, it was hypothesized that post-submergence growth recovery may require efficient photosynthetic acclimation to increased O(2) and irradiance ...

Photosynthetic pigments, biochemical activities and chlorophyll a fluorescence kinetics were investigated to survey the photosynthetic characteristics of Ginkgo biloba L. during leaf growth. The content of total chlorophyll increased rapidly while the content of carotenoids changed a little. The content of ATP, the activity of O2 evolution of chloroplasts, the electron transport activities, the...

We grew velvetleaf (Abutilon theophrasti Medic.) and cotton (Gossypium hirsutum L. var. Stoneville 213) at three irradiances and determined the photosynthetic responses of single leaves to a range of six irradiances from 90 to 2000 mueinsteins m(-2)sec(-1). In air containing 21% O(2), velvetleaf and cotton grown at 750 mueinsteins m(-2)sec(-1) had maximum photosynthetic rates of 18.4 and 21.9 m...

Respiration is an important process in photosynthetic organisms, as it is in other organisms, for the supply of ATP and metabolites required for biosynthesis. Furthermore, individual enzymatic activity is subject to regulation by metabolic intermediates in glycolysis and the citric acid cycle. However, little is known about how glycolysis or catabolism are related to photosynthetic activity or ...

Nitrodiphenylethers, Energy-Transfer Inhibition of ATP Synthesis, Herbicides, Photosynthetic Electron Transport, Pigment Bleaching Nitrodiphenylethers substituted with Cl, CF3, and other comparatively simple substituents are compared with respect to their primary effects on the photosynthetic apparatus. These are direct electron-transport inhibition, energy-transfer inhibition (of ATP synthesis...

Band 7 proteins, which encompass members of the stomatin, prohibitin, flotillin, and HflK/C protein families, are integral membrane proteins that play important physiological roles in eukaryotes but are poorly characterized in bacteria. We have studied the band 7 proteins encoded by the cyanobacterium Synechocystis sp. strain PCC 6803, with emphasis on their structure and proposed role in the a...

Chloroplasts emit signals that modulate nuclear gene expression, thereby ensuring the proper assembly of the photosynthetic apparatus. Recent studies have provided major new insights into one of these signalling mechanisms, and identified the chlorophyll precursor Mg-protoporphyrin IX as a key signalling molecule.

In this paper the response of photosynthesis to stress independently or in combination with other stresses is considered. Some mechanisms by means of photosynthetic apparatus is acclimated to respective stress and enhanced its thermotolerance as well as the role of some heat shock proteins (HSP70, HSP21) and plant growth regulators (polyamines ABA) are also discussed.

Maintaining electron flow through the photosynthetic apparatus, even in the absence of a sufficient amount of NADP as an electron acceptor, is essential for chloroplast protection from photooxidative stress. At least two different pathways are thought to participate in this process, i.e. cyclic electron flow and the water-water cycle. Although the function of the water-water cycle was inferred ...