Native tubular membranes were purified from the purple non-sulfur bacterium Rhodobacter sphaeroides. These tubular structures contain all the membrane components of the photosynthetic apparatus, in the relative ratio of one cytochrome bc1 complex to two reaction centers, and approximately 24 bacteriochlorophyll molecules per reaction center. Electron micrographs of negative-stained membranes di...

Synchronous cell division in cultures of Chlorella vulgaris Beijerinck was induced by intermittent illumination: 9 hours light, 6 hours darkness. The rate of photosynthetic O(2) evolution per cell increases 4-fold in a one-step manner at the beginning of the light period, to the same extent as the increase in cell number. Over the division cycle, the following accumulation times during the ligh...

Treatment of microalgae (B um illeriopsis) with paraquat (l,l-dimethyl-4,4-dipyridylium dichlo­ ride) under culture conditions in the light for 20 or 160 h leads to light-induced oxygen uptake and more or less severe chlorophyll bleaching, which is accompanied by formation of malondialdehyde. The ratio of chlorophyll to packed chloroplast volume remains about the same as that of the control, pr...

Holt, Stanley C. (Dartmouth Medical School, Hanover, N.H.), S. F. Conti, and R. C. Fuller. Photosynthetic apparatus in the green bacterium Chloro-pseudomonas ethylicum. J. Bacteriol. 91:311-323. 1966.-When cells of Chloro-pseudomonas ethylicum were broken by ballistic disruption and examined by electron microscopy, vesicles 1,300 to 1,500 A long and 300 to 500 A wide were found to rim the perip...

Potassium is an essential nutrient for plants and its limited resources impose the improvement of fertilizer-use efficiency. To address this issue, it important to understand roles in photosynthesis provide a quick, noninvasive method diagnosing deficiency plants. The impact potassium on photochemical phase has not been well understood. In work, we present K+-deficiency effect gas exchange, chl...

The photosynthetic apparatus in higher plants has been found to be located in complex lipoprotein membrane systems in the chloroplasts called grana. Electron microscopy has provided invaluable information in determining the fine structure of grana (6-9, 11, 21, 28-30). However, due to the harsh methods employed in fixation (usually by osmium tetroxide or potassium permanganate) and dehydration ...

Safe and efficient conversion of solar energy to metabolic energy by plants is based on tightly inter-regulated transfer of excitation energy, electrons and protons in the photosynthetic machinery according to the availability of light energy, as well as the needs and restrictions of metabolism itself. Plants have mechanisms to enhance the capture of energy when light is limited for growth and ...