Hydrogen accumulation by H2-uptake negative strains of Rhizobium

Summary Hydrogen evolution from root nodules has been reported to decrease the efficiency of the nitrogen fixing system. Mutants ofRhizobium meliloti andRhizobium leguminosarum were selected which were deficient in H₂-uptake capacity (Hup^–). The relative efficiency of the nitrogen fixation for both species assessed with C₂H₂ reduction was 0.66.The hydrogen production was monitored using a simple root incubation method. As such, hydrogen production up to 3.83 and 15.57 ml.day^–1.g^–1 plant dry weight were recorded forPisum sativum — Rhizobium leguminosarum 4.20 Hup^– andMedicago sativa — Rhizobium meliloti 1.5 Hup^– respectively. In a closed container (250 ml), hydrogen concentrations up to 20% (v/v) could be reached in the root phase ofMedicago sativa in a time period of 320 hours.     

The effect of iron chelate fertilization of poplar upon CO2-uptake,leaf size,and content of leaf pigments and iron

Summary Potted poplars (strainsmarilandica, serotina andFlachslanden ofPopulus euramericana) which developed iron-deficiency symptoms (chlorosis of upper leaves, winter die-back of leader, flushing of lateral buds) were treated with a soil application of iron chelate to study the effect of iron nutrition upon CO₂-uptake, iron and pigment content of leaves, and leaf size of a tree species. Foliar content of each iron, chlorophyll, -carotene, lutein, and violaxanthin was significantly increased by the treatment. Chlorophyll b proved to be particularly sensitive to iron supply and the Q^a/b was also significantly altered.CO₂-uptake increased in fertilized and non-fertilized leaves with increasing light up to 40,000 Lux, but fertilized leaves assimilated more CO₂ than non-fertilized leaves, especially at light intensities from 5,000 Lux upwards. The assimilatory number was decreased by the iron application since larger amounts of chlorophyll were present in fertilized leaves. If CO₂-uptake was based upon an area unit basis the fertilizer effect became distinct even at 500 Lux. Thus CO₂-uptake is a quick, valuable measure of fertilizer responses.In severe cases, iron deficiency also affects leaf size and thus indirectly reduces photosynthetic activity. A chelate application during the growing season will not affect the size of leaves already formed but may considerably increase the size of leaves formed subsequent to the treatment.     

The effect of lead contamination of soils and air on its accumulation in pollen

Summary Concentrations of heavy metals in the honey, derived fromAster tripolium was the starting-point for this investigation. Lead content of pollen inAster tripolium andTaraxacum officinale is mainly due to airborne lead. Accumulation of other heavy metals such as zinc and copper in pollen occur mainly via a translocation process from roots to flowers.     

The effect of water potential on soil-borne diseases of wheat seedlings

Under glasshouse conditions, Fusarium culmorum caused more injury to wheat seedlings in soil at 33% saturation (approximately – 1 bar) than at 66% (–0·1 bar). The same effect occurred with inoculated seeds raised on soil moisture tension tables at –0·1 and –0·5 bar, at 20° and at 15°C. In controls, spontaneous infection by soil-borne F. culmorum was unaffected by soil water potential. Inoculated F. nivale, at 127deg; and at 15°C, showed a similar, but smaller, effect to that with inoculated F. culmorum. Water potential in this range did not affect disease incidence with inoculated Gaeumannomyces graminis, but disease was more severe in the drier soil. On tension tables, seedlings did not consistently develop faster under wetter conditions, and factors other than host growth rate probably played a part in limiting fungal attack.     

Effects of long-term open-air exposure to fluoride,nitrogen compounds and SO2 on visible symptoms,pollutant accumulation and ultrastructure of Scots pine and Norway spruce seedlings

 Effects of SO₂, aqueous fluoride (NaF) and a solution of nitrogen compounds (NH₄NO₃) on the visible symptoms, pollutant accumulation and ultrastructure of Scots pine (Pinus sylvestris L.) and Norway spruce [Picea abies (L.) Karst.] seedlings were studied in an open-air experiment lasting for 3 consecutive years. Visible injury symptoms were most pronounced in combination exposures and whenever F was applied. Visible symptoms correlated well with needle pollutant concentrations. Exposure to NaF increased needle F contents particularly when F was applied with SO₂ or NH₄NO₃. This suggests that a reduction in N or SO₂ emissions, in F polluted areas, could improve the condition of conifers via decreased accumulation of phytotoxic F in the needles. Norway spruce needles accumulated 2 – 10 times as much S and F as those of Scots pine. Microscopic observations showed various changes in the needle mesophyll cell ultrastructure. In both species, exposure to SO₂ increased significantly the amount of cytoplasmic vacuoles, suggesting detoxification of excess sulphate or low pH. F treatments resulted in a significant enlargement of plastoglobuli in Scots pine and a darkening of plastoglobuli in Norway spruce. All exposures enhanced the accumulation of lipid bodies. An increased portion of translucent plastoglobuli was most pronounced in N treatments. Many of the ultrastructural changes and visible symptoms appeared only as number of years exposed increased, indicating that long-term experiments are needed. Both visible symptoms and ultrastructural changes pointed to the more pronounced sensitivity of Norway spruce compared to Scots pine. Ultrastructural results mostly supported earlier qualitative observations of F, N and SO₂ effects on needle mesophyll cell ultrastructure. However, no reduction of thylakoids in SO₂ containing exposure or curling of thylakoids in F exposure could be detected in the present study. Received: 5 December 1994 / Accepted: 28 April 1995     

The biological mechanism of air ion action: The effect of CO2+ in inhaled air on the blood level of 5-hydroxytryptamine in mice

Mice inhaling positively ionized air exhibited a significant rise in the blood level of 5-hydroxytryptamine [5-HT]_BL. This effect was duplicated by non-ionized air to which CO₂ ⁺ was added but did not occur when the same amount of either nonionized CO₂ or CO₂ ^– replaced CO₂ ⁺. The rise in [5-HT]_BL was associated with physiological changes that parallel those appearing after the injection of 5-HT or after administration of iproniazid.Some of the animals exposed to CO₂ ⁺ in air became ill and suffered tissue damage attributable to excessive concentrations of 5-HT. A few of the mice died and at autopsy pulmonary and enteric lesions were found which also were reasonably ascribed to the increased 5-HT_BL.The physiological,pathological and biochemical changes described furnish additional support for the 5-HT hypothesis of air ion action presented in earlier publications. There is good reason to believe that some of the known biological effects of gaseous ions involve other mechanisms.

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Zusammenfassung Der 5-Hydroxytryptamin (5-TH) Spiegel im Blut von MÄusen war signifikant erhöht nach Inhalation von positiv ionisierter Luft. Der Effekt wurde bei Zugabe von CO₂ ⁺ Ionen zu nicht-ionisierter Luft verdoppelt; er fehlte, wenn der Luft anstatt CO₂ ⁺, CO₂ ^– oder nicht-ionisiertes CO₂ beigemischt wurden.Mit dem 5-HT Anstieg im Blut kam es zu den typischen physiologischen VerÄnderungen, wie sie nach Injektion von 5-TH oder Iproniazid auftreten. Ein Teil der Tiere, die Luft mit CO₂ ⁺ geatmet hatten,erkrankte an GewebsschÄden, die sonst nach 5-HT überdosierung auftreten; mehrere Tiere starben; die Lungen- und DarmverÄnderungen wurden als Folge des erhöhten 5-HT Blutspiegels gedeutet. Diese physiologischen,pathologischen und biochemischen VerÄnderungen liefern weitere Belege für die Hypothese,dass die Luftionen über das 5-HT wirken. Es sind jedoch Anzeichen vorhanden, daas in den Wirkungsmechanismus der Gasionen noch andere Funktionen einbezogen sind.

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Résumé Des souris inhalant de l'air ionisé positivement ont montré une augmentation significante du taux sanguin de 5-hydrocytryptamine [5-HT]_BL. Cet effet fut reproduit par de l'air non ionisé auquel on avait ajoute du CO₂ ⁺, mais ne se produisit pas quand la mÊme quantité de CO₂ non ionisé ou de CO₂ ^– remplaÇait le CO₂ ⁺. L'élévation de (5-HT)_BL était accompagnée de modifications physiologiques parallèles à celles qui apparaissent après injection de 5-HT ou administration d'iproniazide. Quelques animaux exposés à du CO₁₂ ⁺ dans l'air tombèrent malades et souffrirent de lésions tissulaires attribuables à un excès de 5-HT. Un petit nombre de souris moururent et les lésions pulmonaires et intestinales trouvées à l'autopsie furent attribuées à l'augmentation de (5-HT)_BL. Les observations physiologiques, pathologiques et biochimiques décrites apportent un argument de plus en faveur de l'hypothèse présentée précédemment sur le rÔle de la 5-HT dans l'action des ions gazeux. Il y a de bonnes raisons de penser que quelques effets biologiques connus des ions gazeux sont produits par d'autres mécanismes.

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Labration for rats and mice made by Rainbrook Feed Company.     

Lipid accumulation and CO2 utilization of Nannochloropsis oculata in response to CO2 aeration

In order to produce microalgal lipids that can be transformed to biodiesel fuel, effects of concentration of CO(2) aeration on the biomass production and lipid accumulation of Nannochloropsis oculata in a semicontinuous culture were investigated in this study. Lipid content of N. oculata cells at different growth phases was also explored. The results showed that the lipid accumulation from logarithmic phase to stationary phase of N. oculata NCTU-3 was significantly increased from 30.8% to 50.4%. In the microalgal cultures aerated with 2%, 5%, 10% and 15% CO(2), the maximal biomass and lipid productivity in the semicontinuous system were 0.480 and 0.142 g L(-1)d(-1) with 2% CO(2) aeration, respectively. Even the N. oculata NCTU-3 cultured in the semicontinuous system aerated with 15% CO(2), the biomass and lipid productivity could reach to 0.372 and 0.084 g L(-1)d(-1), respectively. In the comparison of productive efficiencies, the semicontinuous system was operated with two culture approaches over 12d. The biomass and lipid productivity of N. oculata NCTU-3 were 0.497 and 0.151 g L(-1)d(-1) in one-day replacement (half broth was replaced each day), and were 0.296 and 0.121 g L(-1)d(-1) in three-day replacement (three fifth broth was replaced every 3d), respectively. To optimize the condition for long-term biomass and lipid yield from N. oculata NCTU-3, this microalga was suggested to grow in the semicontinuous system aerated with 2% CO(2) and operated by one-day replacement.     

Hydrogen-stimulated CO2 fixation and coordinate induction of hydrogenase and ribulosebiphosphate carboxylase in a H2-uptake positive strain of Rhizobium japonicum

H₂-uptake positive strains (122 DES and SR) and H₂-uptake negative strains SR2 and SR3 of Rhizobium japonicum were examined for ribulosebisphosphate (RuBP) carboxylase and H₂-uptake activities during growth conditions which induced formation of the hydrogenase system. The rate of ¹⁴CO₂ uptake by hydrogenase-derepressed cells was about 6-times greater in the presence than in the absence of H₂. RuBP carboxylase activity was observed in free-living R. japonicum strains 122 DES or SR only when the cells were derepressed for their hydrogenase system. Hydrogenase and RuBP carboxylase activities were coordinately induced by H₂ and both were repressed by added succinate. Hydrogenase-negative mutant strains SR2 and SR3 derived from R. japonicum SR showed no detecyable RuBP carboxylase activities under hydrogenase derepression conditions. No detectable RuBP carboxylase was observed in bacteroids formed by H₂-uptake positive strains R. japonicum 122 DES or SR. Propionyl CoA carboxylase activity was consistently observed in extracts of cells from free-living cultures of R. japonicum but activity was not appreciably influenced by the addition of H₂. Neither phosphoenolpyruvate carboxylase nor phosphoenolpyruvate carboxykinase activity was detected in extracts of R. japonicum.Abbreviations RuBP Ribulose 1,5-bisphosphate - (Na₂EDTA) (Ethylenedinitrilo)-tetraacetic acid, disodium salt - (propionyl CoA) Propionyl coenzyme A - (PEP) Phosphoenolpyruvate - (GSH) Reduced glutathione - (Tricine) N-tris(hydroxymethyl)-methylglycine     

The effect of atmospheric SO2 pollution on the microflora of forest soils

The existing knowledge of the effects of industrial SO₂ immissions on forest soil microflora is reviewed. Most Czechoslovak data were obtained in heavily polluted spruce stands in the Ore Mountain and in the Slavkov Forest (NW Bohemia). The industrial SO₂ immissions soil. Pseudomonads yield to yellow-and red-pigmented microorganisms, among micromycetes there is a higher incidence of the generaRhizopus andMucor. The biochemical capabilities of the bacterial populations are reviewed: the immissions have a negative effect on the occurrence and efficiency of heterotrophic nitrifiers, increase the concentration of autotrophic as well as heterotrophic oxidizers of S⁰ and of sulfite-resistant bacteria. The soil activities of the C and N cycles are inhibited whereas the oxidation of S⁰ is stimulated. Changes in the soil of spruce stands are probably due to intoxication with sulfur dioxide (and possibly with sulfite) rather than to acidification. Replacement of withered spruce stands with mountain ash brings about a dramatic improvement of the soil microflora. Presented at the16th Congress of the Czechoslovak Microbiological Society, Banská Bystrica, October 21–23, 1983.     

Control of 35SO 4 2- and 35SO 3 2- incorporation into spinach chloroplasts during photosynthetic CO2 fixation

In addition to membrane translocation, measured in the dark, it was found that pre-illumination of the chloroplasts resulted in an enhancement of sulfate uptake by 25% and of sulfite uptake by 55% as soon as the concentration of the ion in the incubation medium exceeded 2 mmol l^-1. This amount which is additionally taken up after pre-illumination is less readily exchanged for other ions. Kinetics of the uptake in relation to pre-illumination time and to light intensity closely parallel those of titration of SH-groups by 5,5-dithiobis (2-nitrobenzoic acid). As a consequence, 10^-6 mol l^-1 DCMU completely inhibits the light triggered increase of uptake of both ions. Uncoupling with 10^-6 mol l^-1 CCCP increases the light induced ³⁵SO ₃ ^2- binding, but decreases that of ³⁵SO ₄ ^2- , demonstrating the need of ATP formation to initiate sulfate reduction. Rates of uptake, measured at different intensities of pre-illumination under nitrogen or in the presence of bicarbonate, suggest that the presence of a carbon skeleton increases the binding rate for both ions. With respect to ³⁵SO ₄ ^2- , the data further indicate a rate limiting step (ATP sulfurylase or adenosine 5-phosphosulfate sulfotransferase) which is activated by light, thus representing a control step to harmonize the rate of CO₂ fixation and of sulfate incorporation. On the contrary, ³⁵SO ₃ ^2- is directly bound in relation to the amount of SH-groups, which in turn are created by the photosynthetic electron transport, resulting in Car-S-SO ₃ ^- . Since the formation of SH-groups is maximal already at low light intensities, no effective control step for SO ₃ ^2- incorporation is indicated.     

The Impact of Indigenous Microorganisms on the Mineral Corrosion and Mineral Trapping in the SO2 Co-injected CO2-Saline-Sandstone Interaction

The impact of indigenous microorganisms on the mineral corrosion and mineral trapping in the SO₂ co-injected CO₂-saline-sandstone interaction was investigated in this study by lab experiments under 55?°C, 15?M pa. The results verified that co-injection of SO₂ resulted in a decrease in biomass and shifts in microbial communities within 90?days, but some microorganisms still could adapt to acidic, high-temperature, high-pressure, and high-salinity environments. Firmicutes and Proteobacteria remained dominant phylum, but phylum Proteobacteria showed better tolerance to the co-injection of SO₂ in the initial period. In the SO₂ co-injected CO₂-saline-sandstone interaction under microbial mediation, acid-producing bacteria further promoted the corrosion of K-feldspar, albite, and clay minerals, meanwhile mobilizing more K⁺, Na⁺, Ca²⁺, Mg²⁺ into solution. The acidogenic effect may be linked to the dominant genus of Bacillus, Paenibacillus, Acinetobacter, Pseudomonas and Exiguobacterium. Co-injection of SO₂ inhibited the carbonates capture, while microbial acid production further reduced the pH, further inhibiting carbonates capture. As a result, no secondary carbonate (e.g., calcite) was observed on a short time scale within 90?days. So, microbial acidogenic effect was not conducive to carbonates capture in short term.     

开放式空气CO2增高对水稻物质生产与分配的影响

在大田栽培条件下,研究开放式空气CO2增加(FACE)200μmol·mol^-1的处理对水稻物质生产与分配的影响．结果表明,FACE处理使移栽至抽穗后20d的干物质积累量显著增加,使抽穗后20d至成熟期的干物质生产量显著减少,生物产量显著提高．移栽至抽穗期的干物质积累量增加是由于叶面积系数和净同化率共同提高所致;抽穗期至抽穗后20d的干物质积累量增加主要是由于叶面积系数的增加所致;抽穗后20d至成熟期的干物质生产量减少主要是由于净同化率的下降所造成．提高茎鞘占全株干物重的比例,降低叶片占全株干物重的比例,对穗占全株干物重的比例无显著影响,能显著提高水稻抽穗期茎鞘中可溶性糖、淀粉的含有率和含量,提高FACE处理的生物产量能极显著提高水稻产量(r＝0．7825)．     

A portable system for simultaneous measurement of transpiration and CO2 exchange

A portable field system for simultaneous measurement of transpiration and CO₂ exchange from leaves of fruit trees is described. CO₂ concentration is measured by means of infra-red gas analysis, using small gas samples collected in syringes. Methods for analysing small gas samples are compared. The leaf chamber described can also be used in a conventional laboratory open gas-exchange system, its small volume permitting measurement of very rapid changes in gas exchange in response to experimental stimuli.

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Resumen Este artículo describe un sistema portátil para medir simultaneamente transpiración e intercambio de CO₂ en hojas de árboles frutales en el campo. Para medir la velocidad de fotosíntesis se colectan pequeñas muestras de gas en jeringas y se inyectan al analizador de gases de luz infra-roja. Se comparan varios métodos para analizar las muestras. Se describe la cámara de absorción de CO₂ utilizada, la cual puede tambien incorporarse a un sistema abierto convencional, su pequeño volumen permite detectar cambios rápidos en el intercambio de gases cuando se producen alteraciones en el ambiente.