The organization of protein complexes in the thylakoid membranes of photosynthetic organisms is closely linked to the functioning and efficiency of energy conversion processes. However, there is currently a lack of detailed knowledge concerning the organization of protein complexes in cyanobacterial thylakoid membranes, We applied a combination of high resolution microscopy imaging techniques t...

Gross ecosystem productivity (GEP) in tropical forests varies both with the environment and with biotic changes in photosynthetic infrastructure, but our understanding of the relative effects of these factors across timescales is limited. Here, we used a statistical model to partition the variability of seven years of eddy covariance-derived GEP in a central Amazon evergreen forest into two mai...

Photosynthesis is the source of our food and fiber. Increasing world population, economic development, and diminishing land resources forecast that a doubling of productivity is critical in meeting agricultural demand before the end of this century. A starting point for evaluating the global potential to meet this goal is establishing the maximum efficiency of photosynthetic solar energy conver...

Several recent studies of energy transfer in photosynthetic light harvesting complexes have revealed a subtle interplay between coherent and decoherent dynamic contributions to the overall transfer efficiency in these open quantum systems. In this work we systematically investigate the impact of temporal and spatial correlations in environmental fluctuations on excitation transport in the Fenna...

Potassium is a major nutrient which may play an important role in many processes such as ion homeostasis in plant cells and osmotic adjustment of guard cells during stomatal opening and closing. Pathumthani 1 (PT1) rice has been reported as being a salt sensitive cultivar and has been selected as a model plant in this study to investigate the possibility of improving the osmotic potential, pigm...

All preceding investigations on the quantum efficiency of photosynthesis, starting with the early experiments of Warburg and Negelein (1922a, b) and Emerson and Lewis (1939, 1941) are performed under low irradiances, even under light compensation point, assuming that the photosynthetic “light curves” are linear and the quantum efficiency of photosynthesis is maximum under these conditions. Howe...

Photosynthetic data collected from Pisum sativum L. and Phaseolus vulgaris L. plants at different stages of development were related to symbiotic N(2) fixation in the root nodules. The net carbon exchange rate of each leaf varied directly with carboxylation efficiency and inversely with the CO(2) compensation point. Net carbon exchange of the lowest leaves reputed to supply fixed carbon to root...

Quantum yield measurements were made with the red alga Porphyridium cruentum, cultured so as to give different proportions of chlorophyll and phycobilins. Totally absorbing suspensions were used so that there was no uncertainty in the amount of energy absorbed. These measurements have shown that chlorophyll, in this alga, has a photosynthetic efficiency as high as in other algal groups, and hig...

Oxygenic photosynthesis in plants involves highly reactive intermediates and byproducts that can damage the photosynthetic apparatus and other chloroplast constituents. The potential for damage is exacerbated when the amount of absorbed light exceeds the capacity for light energy utilization in photosynthesis, a condition that can lead to decreases in photosynthetic efficiency. A feedback de-ex...

The release of nanoparticles into the environment is inevitable, which has raised global environmental concern. Melatonin is involved in various stress responses in plants. The present study investigated the effects of melatonin on photosynthetic carbon (C) assimilation and plant growth in nano-ZnO stressed plants. It was found that melatonin improved the photosynthetic C assimilation in nano-Z...