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This paper reports on seasonal cycles of physical and chemical factors, over a period of two years, which were expected to affect the size and seasonal variation of phytoplankton production in the eutrophic, dimictic Lake Esrom, Denmark. Insolation, transparency, temperature, oxygen, total carbon dioxide, free carbon dioxide, pH, alkalinity, silicate, nitrate, ammonia, orthophosphate and total phosphate, were measured to describe the lake hydrography. They are presented as isopleths. After the spring maximum of phytoplankton, nitrogen and silica rapidly declined to insignificant and limiting concentrations while phosphate- phosphorus declined to 50% (150 μg litre-1) of the winter value. Light can limit phytoplankton production at all seasons. A phosphorus balance showed that there was about 80 t of phosphorus in the lake. Phoshorus recycled in the lake ecosystem was 20 t, 10 t from tributaries and 10 t annually being added to the sediment. The evidence for enrichment includes a discussion on the history of the lake, coring, ground water analyses, changes in hypolimnetic dissolved oxygen, and changes in transparency. The possible influence of pollution from sewage is discussed in relation to the estimated nutrient budget of nitrogen and phosphorus. Increase in nutrients failed to increase phytoplankton production during 17 years. [ABSTRACT FROM AUTHOR]

When 8-day seedlings were exposed to 14CO2 in light, approximately 2 hours were required for 14C to reach the apices of the roots. One method used to detect the progress of 14C down the root was to scan the root with a radiochromatogram strip scanner. At this stage most in aqueous ethanol extracts of roots was present as sucrose, equally labelled in glucose and fructose. This was converted only slowly to other components of the soluble fraction so that after 12 hours almost 50% of 14C was still retained in sucrose. 14C exuded from intact roots into surrounding solutions was present in both volatile and non-volatile compounds. In the non-volatile fraction glutamine, glutamic and aspartic acids were the main 14C-amino acids. Exudation of 14C was not affected by changing the inorganic composition of the collecting solution. A change in pH of collecting solution from 6.4 to 5.9 increased exudation. Exudation also increased markedly when 2,4-dinitrophenol or potassium cyanide was present in the collecting solution. [ABSTRACT FROM AUTHOR]

This article presents a quantitative investigation regarding the composition of wet-heath vegetation in relation to aeration of the ground water and soil in certain communities on the north Hampshire-Berkshire border. The study shows that the cover of several species was closely related to the concentrations of carbon dioxide and hydrogen sulphide in the ground water, particularly Molinia coerulea, that cover decreased as the concentrations of these gases increased. Furthermore, it was concluded that their intercellular space system provided a free path for the oxygen diffusion from shoot to root.

Young plants of the wilty tomato mutant, flacea, in which the stomata resist closure, were sprayed with abscisic acid eight times over a period of 24 hours in light and darkness. The hormone induced closure of stomata similarly in leaves treated either in light or in darkness. Abscisic add does not appear to induce stomatal closure in darkness by increasing the internal CO2 concentration in the leaf, since this concentration should already be very high in darkness. A considerable and rapid decrease of CO2 assimilation and increase of CO2 evolution were demonstrated in mutant as well as in normal plants transferred from light to darkness. [ABSTRACT FROM AUTHOR]

The state of knowledge of the transition of sapwood into heartwood in trees is reviewed, and attention is drawn to the composition of the gas mixture available to such cells as remain alive in wood. The probable effect of such a mixture is postulated and experiments indicate that the high concentrations of carbon dioxide known to exist inside wood are conducive to formation of compounds known to be typical of the heartwood of Acacia mearnsii. [ABSTRACT FROM AUTHOR]

Four mosses, Bryum argenteum, Grimmia pulvinata, Hypnum cupressiforme and Tortula muralis were exposed to sulphite, and their uptake of radioactive bicarbonate measured. About 50% reduction in 14C uptake was caused by 0.01-0.1 mM suiphite. The effect of pH indicated that SO2 (or H2SO3') was the active molecular species. Fluoride had little effect on 14C uptake. [ABSTRACT FROM AUTHOR]

Uninfected plantlets of Goodyera repens and plantlets infected with the endophyte Rhizoctonia goodyerae-repentis were fed with 14CO2. Quantities of 14C fixed varied greatly between individuals, but there was a consistent pattern of distribution of label which remained unaltered over four weeks. Very little 14C moved to the rhizomes. The endophytic fungus readily grew from infected plantlets on to Pfeffer agar and small amounts of radioactivity were found in the mycelium growing from previously fed plantlets. 14C leakage from uninfected plantlets was negligible, although low levels of radiactivity occurred in serial washings from them. When the tops alone of infected plants were fed with 14CO2, no radioactivity could be detected in the emerging fungal mycelium. Where rhizomes alone were exposed, small quantities of 14C were detected in the growing mycelium. The fungus readily translocated 14C from the remains of dead protocorms. It appears that R. goodyerae-repentis does not freely utilize recent photosynthate from its host under the conditions of these experiments. [ABSTRACT FROM AUTHOR]

A system is described for measuring in situ CO2 evolution rates from forest soil. The apparatus incorporates an infrared gas analyzer with open air flow through 10 chambers which sequentially lower over the forest floor during measurements and raise after measurements are complete. Unlike methods using stationary chambers, this system allows litter and soil horizons to undergo a natural drying cycle. Litter moisture under stationary chambers was 76% of dry weight at the end of a 3-day sample period as compared to 40% under moving chambers and 39% in control plots. Carbon dioxide evolution rates from plots enclosed by stationary chambers ranged from 54 to 90% higher than those from moving chamber plots. Effects of such discrepancies in calculating the carbon balance of forest ecosystems are discussed. Application of the moving chamber apparatus in monitoring gaseous losses from biodegradable waste such as by-products of petroleum is also discussed. [ABSTRACT FROM AUTHOR]

The article presents a study on the association between alkaline phosphatase activity and freshwater bacteria and algal populations. The study involves a survey on the Windermere North and South Basins and Esthwaite Water at the south end of the lake, and the establishment on the association between the bacteria and phytoplankton. It was found out that the carbon dioxide produced by the bacterial populations related with the algae could be responsible for the initiation or simulation of an algal bloom in the natural environment.

The article discusses some comparative studies on photosynthesis, respiration and water relations of 10 arid zone and two semi-arid zone plants under winter and late summer climatic conditions. Data on carbon dioxide exchange and water relations were obtained for eight arid and two semi-arid zone native plant species of Western Australia. In late summer, all species showed a positive carbon dioxide balance which indicates that there is sufficient soil water in deeper soil layers. All the species tested possess a high heat resistance and are well suited to their natural environment.

The article presents a study on the biomass cycle of tropical rain forests. It mentions that since rain forests are climax communities, it can be expected that the rates of production and decomposition of organic matter are equal. The rate of soil respiration including the cycle of carbon dioxide can be used to measure the net productivity of rain forests. Plastic cylinders containing potassium hydroxide were used to absorb carbon dioxide in the area. The experiment was carried out from March 12 to 16, 1969 at Tjibodas, Java. It found that decomposition of organic matter is faster in tropical rain forests. It also recommends a longer period for the experiment. An overview of the results of the study is provided.

The article presents a study which assesses the interaction of the daily compensation period (DCP) of mosses and lichens and the ecological ranges of tree species in Japan. It states that some of the species were not able to reach the compensation point due to the negative level of carbon dioxide on cloudy and rainy days. It reveals that mosses and lichens require two and four hours to reach the compensation point. It concludes that the species could not grow below their ordinary habitats because their vitality may be impaired.

The article examines the seasonal fluctuations in the oxygen and carbon dioxide concentrations in beech litter in connection to the salt uptake of beech mycorrhizas. To estimate the oxygen and carbon dioxide concentrations in the litter layer of beech woods in which mycorrhizal roots are abundant, a method was developed in conjunction with experiments studying the uptake of phosphate by excised mycorrhizal roots of Fagus sylvatica. The two types of experiments conducted included an examination of the effect of oxygen concentration on the uptake of phosphorus and its distribution between fungus and host and the determination of the distribution of phosphorus between the fungus and host.

The article presents a discussion about the rain forest of Southern Nigeria based from the ecological studies conducted on the said region. The article explores the climate, topography, ecology, and botany of the rain forest through the various studies and includes details regarding environmental aspects such as the carbon dioxide concentration of the environment, light, temperature and humidity, and soils. The article ends with a summary which states that in the area concerned, primary forest will be established again on abandoned land after cultivation.

The article presents a study regarding atmospheric environmental conditions of the rain forest in southern Nigeria. Carbon dioxide concentration in the tropical rain forest undergrowth and temperate woods was not observed to exceed 0-06% by volume. There are no significant differences between the concentrations in primary and secondary forests. Data from the thermohygrograph records of the temperature and humidity conditions in the tree tops and undergrowth are presented. Discussion regarding the possible effects of Nigeria's environmental conditions on the life of undergrowth plants is also presented.

1. Brown adipose tissue is thermogenically active when coupling of oxidative phosphorylation is loosened. Brown-adipose-tissue mitochondria when fleshly isolated are uncoupled. They are brought to a coupled state by oxidation of endogenous fatty acids, after which addition of exogenous fatty acids produces a burst of oxygen consumption. This does not correspond to that theoretically required for complete oxidation of the added fatty acid to carbon dioxide and water. 2. Oxidation by coupled mitochondria of 14C-labelled palmitic acid in the presence of malate leads to labelling of water-soluble intermediates. 3. These intermediates are identified as citric acid cycle intermediates, amino acids arising from transamination, and acetyl L-carnitine. 4. It is found that m coupled and uncoupled conditions the ratio of acetyl L-carnitine to other intermediates is altered. Uncoupling reduces the formation of acetyl L-carnitine and increases entry of acetyl groups into the citric acid cycle. 5. A control mechanism for this process and its possible correlation with the physiological function of brown adipose tissue are discussed. [ABSTRACT FROM AUTHOR]

The reaction of 5,5'-dithiobis, 3,3'-nitrobenzoic acid with hemoglobin and isolated chains has been studied and the functional properties of the derivatives have been determined. The oxygen affinity of treated hemoglobin, both at low and high salt concentration is higher than that of normal hemoglobin under the same conditions with no substantial change in heme-heme interaction; the Bohr effect is somewhat reduced in the alkaline range, but is increased in the acid range. The treated β-chains show enchanced oxygen affinity with respect to normal chains. Treated hemoglobin shows also, in comparison with normal hemoglobin, significant changes in the kinetics of CO binding and O2 dissociation. [ABSTRACT FROM AUTHOR]

14C-labeling experiments with growing Clostridium kluyveri have shown that two pathways each are operative for glycine and one-carbon unit synthesis: about two-thirds of the cell's glycine is formed from threonine and one third icon serine; serine simultaneously yields about a quarter of the cell's C1-units, while the remaining three-quarters are derived from CO2 via the pyruvate carboxyl group. The key enzymes, threomine aldolase and pyruvate formate lyase as well as serine aldolase interrelating glycine and C1-unit synthesis, could be demonstrated in cell-free lysates in activities sufficient to account for the anabolic requirements during growth. The substrate specificity, cofactor requirements and Km values indicate that threonine aldolase and serine aldolase are two separate, constitutive and pyridoxal phosphate dependent enzymes. [ABSTRACT FROM AUTHOR]

Human lactoferrin, the red iron-binding protein from milk, was prepared by chromatography on DEAE-cellulose of the milk proteins soluble in 2 M ammonium sulfate. Several preparations differing in iron content were obtained. Apolactoferrin was prepared by dialyzing the protein against 0.1 M citric acid. Saturation experiments with iron ascorbate indicated the iron : protein ratio at saturation to be 0.025 micromoles of metal per mg of protein. Assuming 80,000 to be the molecular weight of lactoferrin, this would correspond to a ratio of two iron atoms per molecule. With copper, a similar molar proportion at saturation was obtained. Gasometrie measurements were used to calculate the amount of carbon dioxide liberated upon dissociation of the metal-protein complexes by acidification. One mole of CO2 was freed per atom of iron or copper. [ABSTRACT FROM AUTHOR]

The limitations of present methods for describing the relative importance of different processes in controlling rates of photosynthesis are discussed, and a new method proposed. It is suggested that 'photosynthetic limitations', instead of resistances, should be used to describe the relative importance of different component processes at normal ambient carbon dioxide concentrations. The limitation approach is particularly relevant if the photosynthetic rate is not limited entirely by the supply of carbon dioxide. [ABSTRACT FROM AUTHOR]

The incorporation of radioactivity into polyols and carbon dioxide was measured for cultures of Dendryphiella salina incubated in media containing [1-14C]- or [6-14C]-glucose, with nitrate, ammonium or glutamate as nitrogen sources. The labelling patterns show that mannitol is synthesized partly via a direct route from substrate glucose and partly from hexose-phosphate derived from the pentose-phosphate pathway. Rapid turnover of the mannitol pool and the redistribution of radioactivity caused by the symmetry of the mannitol molecule lead to the synthesis of labelled arabitol from both forms of radioactive glucose. After a 6-hour incubation period, the proportion of mannitol synthesized via the pentose-phosphate pathway ranges from 36% in nitrate media to 19% in glutamate media. C1/C6 ratios for yields of 14CO2 also indicate that the activity of the pentose-phosphate pathway is greatest in the nitrate media and least in the presence of glutamate. Furthermore, there is an increase in the C1/C6 ratio when nitrate or methylene blue is added to cultures in ammonium media. The results are discussed in relation to previous studies of the pentose-phosphate pathway in fungi containing mannitol. [ABSTRACT FROM AUTHOR]

Freshly-cut slices of mature tubers liberated little 14CO2 from [2-3 14C] succinate even when sprouting after 9 months storage at 5 °C. Output from 24-hour washed slices was considerable; it increased in amount with increasing length of storage period and was enhanced when light was excluded during washing and incubation in succinate. A comparison was made between non-tuberizing stolon tips and young tubers taken within a day or so of tuber initiation. The fresh stolon tips released an appreciable quantity of CO2 from succinate, much less after washing. Fresh young tubers liberated much less 14CO2, slightly more after washing. Although tiffs indicated that the tricarboxylic acid- (TCA-) cycle block might arise soon alter initiation, the qualitative distribution of the label in tissue extracts showed stolon tips and young tubers to be similar to each other and distinct from mature tuber tissue. [ABSTRACT FROM AUTHOR]

Discusses species characteristics in whole plant resistances to water vapor and carbon dioxide diffusion. Effect of gaseous diffusion process in the leaf on photosynthesis and transpiration; Desert species which were investigated in the laboratory; Comparison of resistance values between species.

Both [14C]carbamoyl phosphate and sodium [14C]cyanate injected in rats were extensively incorporated into blood proteins, red cells and tissues, including brain. The rate of cyanate binding to blood protein plateaus 4 h after intraperitoneal administration of [14C]cyanate. The rapid disappearance of free [14C]cyanate was shown to be largely due to protein binding and the release of 14CO2 was found to decrease sharply at 4 h when cyanate binding is essentially complete. Retention of carbamoylated proteins was measured after injection of [14C]cyanate, and at 110 days, when bound radioactivity in blood protein was negligible, brain protein retained about 50% of the radioactivity found at 6 h. A dose-related decrease m learning ability was observed when rats injected with 50, 100 and 150 µmol cyanate per day were tested in a Lashley maze No. III filled with water. This retardation persisted when the animals were reused nine weeks after termination of cyanate injection. When retested at eight months, no retardation could be demonstrated. At this time, only 10% modified proteins should remain in the brain according to the data presented on retention of carbamoylated proteins. The application of this data to a biochemical model for learning based on synaptic facilitation by modified proteins is discussed, as well as the implied effect on humans treated for sickle-cell disease by administration of cyanate or carbamoyl phosphate. [ABSTRACT FROM AUTHOR]

1. Kinetic studies of the overall reaction between NADPH, ribulose 5-phosphate and dissolved CO2, catalysed by 6-phosphoglnconate dehydrogenase purified from sheep liver, were made at pH 7.0 in triethanolamine buffer. 2. From relationships among the initial-rate coefficients for various mechanisms for three substrate reactions, the results indicate a compulaory-order mechanism in which NADPH combines first and CO2 last. From the Haldane relation between kinetic coefficients for quaternary complex mechanisms, a value of 66 mM was obtained for the equilibrium constant at 25 °C in satisfactory agreement with the value of 79 mM from direct determinations. 3. Michaelis constants for NADPH, ribulose 5-phosphate and CO2 are 0.22 μM, 20.0 μM and 34 mM, respectively. The maximum specific rate is 1.0 sec-1. [ABSTRACT FROM AUTHOR]

The article a simple modification of the polymer membrane electrode which has proved to be convenient for measurements of the partial pressure of carbon dioxide in the soil. The system is not suitable for following short-term fluctuations in carbon dioxide pressure and has the disadvantage that a considerable volume of carbon dioxide is lost from the soil. The device used consists of a Pyrex test tube with a hole blown in the side near the base and covered with 0-005-inch thick polytetrafluoroethylene adhesive-backed tape.