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1.
Effect of Interactions Among Algae on Nitrogen Fixation by Blue-Green Algae (Cyanobacteria) in Flooded Soils 总被引:1,自引:1,他引:0 下载免费PDF全文
Nitrogen fixation (C2H2 reduction) by algae in flooded soil was limited by interactions within the algal community. Nitrogen fixation by either indigenous algae or Tolypothrix tenuis was reduced severalfold by a dense suspension of the green alga Nephrocytium sp. Similarly, interactions between the nitrogen-fixing alga (cyanobacterium) Aulosira 68 and natural densities of indigenous algae limited nitrogen-fixing activity in one of two soils examined. This was demonstrated by developing a variant of Aulosira 68 that was resistant to the herbicide simetryne at concentrations that prevented development of indigenous algae. More nitrogen was fixed by the resistant variant in flooded soil containing herbicide than was fixed in herbicide-free soil by either the indigenous algae or indigenous algae plus the parent strain of Aulosira. Interference from indigenous algae may hamper the development of nitrogen-fixing algae introduced into rice fields in attempts to increase biological nitrogen fixation. 相似文献
2.
Summary a)Nitrogen fixation in rice fields. Nitrogen-fixing blue-green algae grow abundantly in tropical regions and are particularly common in paddy fields. Their
possible role in the nitrogen accumulation of soil has been studied. The most vigorous nitrogen-fixing blue-green algae have
been assessed for use as green manure in rice fields and favorable effects have been reported in India and other countries.
b)Nitrogen fixation by algae in water. The planktonic blue-green algae occur abundantly at certain time of the year in sea water and lake water, and some of them
are known to be nitrogen fixers. Certain Japanese species of blue-green algae can withstand high temperatures including ten
nitrogen-fixing species from hot-spring waters.
c)Nitrogen fixation by symbiotic blue-green algae. Certain species of blue-green algae form associations with other organisms such as fungi, liverworts, ferns and seed plants.
The relationship between these two organisms is on one occasion commensal and on others symbiotic. Certain symbiotic blue-green
algae are provided with the ability to fix the atmospheric nitrogen. 相似文献
3.
G. E. Fogg 《Plant and Soil》1971,35(1):393-401
Summary Determinations in the open waters of lakes using N15 as a tracer show that nitrogen fixation is generally associated with the presence of heterocystous blue-green algae and is
light dependent. Although nitrogen-fixing blue-green algae tend to be abundant when the concentration of nitrate or ammonia
in the water is low, fixation itself is not necessarily inhibited by the presence of these sources of combined nitrogen. The
activity of nitrogen-fixing blue-green algae shows a direct relationship to concentration of dissolved organic nitrogen.
As a result of the interaction of such factors, nitrogen fixation per unit area of lake surface per year tends to be greatest
at an early stage of eutrophication. In relation to the total nitrogen budget of a lake the contribution of biological nitrogen
fixation to the income is probably always small but at certain times and in particular water strata it may contribute a major
part of the nitrogen assimilated by the phytoplankton. 相似文献
4.
The Effects of Moisture on Acetylene Reduction by Mats of Blue-green Algae in Sub-tropical Grassland 总被引:1,自引:0,他引:1
During the dry winter months desiccation is the main factorpreventing nitrogen fixation by mats of blue-green algae inkikuyu lawns. In the wetter summer months a few days of sunshinewithout rain will dry out the algal mats and depress nitrogenfixation unless the algae are protected by swards of grass.Dry mats resume nitrogen fixation within an hour of becomingdamp and attain their normal rate of fixation within 5 h. Maximumfixation rates occur at 100 per cent relative humidity and withsoil moisture contents of 22 to 42 per cent. Dry algal matsare unable to take up sufficient water as vapour (even in saturatingconditions) to permit resumption of acetylene reduction. Algal-dominatedsoils show greater water retention than adjacent bare soils. 相似文献
5.
6.
Summary An in situ device for assaying biological nitrogen fixation in flooded rice soils, using the acetylene reduction method, was developed.
Diurnal variations in acetylene reduction by an inoculated field plot and by laboratory-grown cultures of nitrogen-fixing
algae showed a prominent single-peak pattern of nitrogenase activity. The peak occurred at mid-day for laboratory-grown algae
and at late afternoon for the algae grown in the field plot. Some nitrogenase activity was noted during the night.
Acetylene reduction studies in rice fields of Albay province, Philippines, showed an estimated fixation of 18.5 to 33.3 kg
N/ha each cropping season for the fields of Puro soil and 2.3 to 5.7 kg N/ha each cropping season for the fields of Santo
Domingo soil. re]19751202 相似文献
7.
Diurnal variation in n(2) fixation and photosynthesis by aquatic blue-green algae 总被引:5,自引:0,他引:5 下载免费PDF全文
Rates of 14CO2 fixation, O2 evolution, and N2 fixation (acetylene reduction) by natural populations of blue-green algae recovered from Lake Mendota were measured at frequent intervals between sunrise and sunset. Photosynthesis and N2 fixation were depressed during midday when light intensity was greatest. As the light intensity rose, most of the algal population migrated to deeper, light-limited waters where radiation damage would be diminished. As the relative rate of N2 fixation compared to CO2 fixation increases with depth, it is suggested that the algae maintain balanced growth by migrating vertically via buoyancy regulation. High concentrations of dissolved O2 in lake water may inhibit N2 fixation by enhancing photorespiration. Several factors such as photosynthetic rate, light intensity, dissolved O2, species composition, and vertical and horizontal migration all affect observed rates of in situ N2 fixation. 相似文献
8.
Lars Leonardson 《Oecologia》1984,63(3):398-404
Summary Phytoplankton net carbon uptake and nitrogen fixation were studied in two shallow, eutrophic lakes in South Sweden. Ranges of diurnal net carbon uptake were estimated by subtracting 24-h respiration rates corresponding to 5–20% of P
max, respectively, from daytime carbon uptake values. total nitrogen requirement of the phytoplankton assemblage was determined from the diurnal net carbon uptake, assuming a phytoplankton C:N ratio of 9.5:1. Nitrogen supplied by nitrogen fixation only occasionally corresponded to the demands of the total phytoplankton assemblage. When heterocystous algae made up a substantial proportion (10%) of the total phytoplankton biomass, nitrogen fixation could meet the requirements of heterocystous blue-green algae on c. 50% of the sampling occasions. Nitrogen deficiencies in heterocystous algae were most probably balanced by the simultaneous or sequential assimilation of dissolved inorganic nitrogen. It was concluded that uptake of ammonium or nitrate, regenerated from lake seston and sediment, is the main process by which growth of phytoplankton is maintained during summer in the lake ecosystems studied. 相似文献
9.
W. D. P. Stewart 《Plant and Soil》1971,35(1):377-391
Summary The various types of blue-green algae known to fix nitrogen are considered. Particular attention has been paid to the effects
of oxygen and other physiological parameters on nitrogenase activity and on the ecological distribution of the group. Data
on nitrogen fixation by cell-free extracts of blue-green algae are presented. 相似文献
10.
Fixation of Elemental Nitrogen by Marine Blue-green Algae 总被引:1,自引:0,他引:1
Three blue-green algae, Calothrix scopulorum, Nostoc entophytum,and Oscillatoria brevis, isolated from the upper littoral andsupralittoral fringe of the sea-shore were obtained in pureculture and tested for fixation of elemental nitrogen. Appreciablefixation by Calothrix and Nostoc was detected, a proportionof the total nitrogen fixed being liberated into the culturemedium. There was no evidence of fixation by Oscillatoria. Thisappears to be the first evidence that blue-green algae isolatedin pure culture from marine habitats fix nitrogen. 相似文献
11.
Birgitta Englund 《Oecologia》1978,34(1):45-55
Summary Nitrogen fixation (C2H2 reduction) by blue-green algae occurring on the juvenile lava field of Heimaey, Iceland was examined both in the laboratory (potential at 20° C and 39° C) and in the field, three and a half years after the volcanic eruption.Already at this early stage of colonization representatives of unicellular and filamentous heterocystous and non-heterocystous blue-green algae were commonly observed. The predominating algae were Nostoc sp. (20° C) and Schizothrix sp. — Microcoleus chthonoplastes, (39° C), the former often in association with the protonemata-rhizoids of moss plants.The potential for nitrogen fixation was recorded at an average rate of 109.2 (20° C) and 138.1 (39° C) ng N g-1 h-1 in soil collected from localities randomly distributed over the lava field.Tests for nitrogen fixation performed in situ revealed significant fixation activities in all the eleven localities subject to examination. The activities ranged from 2.8 to 63.4 (mean 21.5) ng N g-1 h-1 and 1.9 to 17.7 (mean 7.9) ng N cm-2 h-1.All the nitrogen fixation data noted imply that blue-green algae contribute a substantial part of the nitrogen input to the lava. Further, it was found that material incubated under micro-aerophilic conditions exhibited considerably enhanced nitrogenase activity.The role of nitrogen-fixing blue-green algae in general and Nostoc muscorum in particular in being suitable as pioneering organisms preparing the bare lava for ingress of other plants is also discussed. 相似文献
12.
Precambrian reduced carbon is more depleted in13C than what would be expected from the carbon isotopic composition of modern marine algae and algal mats. Since the photosynthetic carbon fixation by algae is the most likely source of the reduced carbon, the depletion has been considered an anomaly.We examined factors that might have contributed to the carbon isotope fractionation from inorganic sources through algae to organic matter in a sedimentary rock, and related laboratory obtainable data to those from Precambrian rocks. Laboratory culture experiments were then performed with nine strains of algae at various concentrations of carbon dioxide, and the result was interpreted according to the relationship.It indicated that the depletion could be understood in terms of a combined effect of fractionation factors, most depletion occurring at the fractionation during the photosynthetic carbon fixation. It also suggested that all but one algal strain incorporated bicarbonate as the source of carbon for its growth. The exception was a thermophilic, acidophilic alga, which must have used carbon dioxide as the carbon source.The present study suggests that Precambrian atmosphere was enriched in carbon dioxide roughly two orders of magnitude more than its present atmospheric level. 相似文献
13.
Reisky Lukas Stanetty Christian Mihovilovic Marko D. Schweder Thomas Hehemann Jan-Hendrik Bornscheuer Uwe T. 《Applied microbiology and biotechnology》2018,102(16):6987-6996
Applied Microbiology and Biotechnology - Carbohydrates are the product of carbon dioxide fixation by algae in the ocean. Their polysaccharides are depolymerized by marine bacteria, with a vast... 相似文献
14.
ULF GRANHALL 《Physiologia plantarum》1976,38(3):208-216
The present study gives evidence for the presence of cellulose in the heterocyst envelope of blue-green algae by means of electron microscopy, cellulase treatments and specific staining and demonstrates the role of this cellulose for the protection of the heterocyst nitrogenase during acetylene reduction. Experiments with lysozyme and cellulase suggest that nitrogen fixation in heterocystous blue-green algae under aerobic conditions is functionally effective only when an intimate relationship exists between vegetative cells and heterocysts and both cell types have intact wall structures. 相似文献
15.
16.
Deep placement: A method of nitrogen fertilizer application compatible with algal nitrogen fixation in wetland rice soils 总被引:3,自引:0,他引:3
Summary The effect of different methods of nitrogen fertilizer application on the algal flora and biological nitrogen fixation (Acetylene-reducing activity) in a wetland rice soil was studied in pot and field experiments. Broadcast application of urea inhibited nitrogen fixation and favored the growth of green algae. In contrast, deep placement of urea supergranules (1–2 g urea granules) did not suppress the growth of N2-fixing blue-green algae and permitted acetylene-reducing activity on the soil surface to continue virtually uninhibited. 相似文献
17.
Grant AJ Trautman DA Frankland S Hinde R 《Comparative biochemistry and physiology. Part A, Molecular & integrative physiology》2003,135(2):337-345
In many cnidarians, symbiotic algae live within host-derived symbiosomes. We determined whether a symbiosome membrane alters the response of isolated symbiotic algae to two signalling compounds that regulate algal carbon metabolism. Host release factor (HRF), which stimulates photosynthate release, and photosynthesis inhibiting factor (PIF), which inhibits photosynthetic carbon fixation, are found in homogenised tissue of the scleractinian coral Plesiastrea versipora. Compared with seawater controls, photosynthate release from isolated algae incubated in P. versipora homogenate for 2 h in the light was: 6 to 19-fold higher from its own algae (free of symbiosomes); 19 to 32-fold higher from Zoanthid robustus algae (within symbiosomes) and 3 to 24-fold higher from Z. robustus algae (free of symbiosomes); and from cultured algae (free of symbiosomes) was seven-fold higher from Montipora verrucosa and four-fold higher from Cassiopeia xamachana. Incubation of algae in P. versipora homogenate inhibited photosynthesis by: 33-49% in P. versipora algae; 29-47% in Z. robustus algae (regardless of whether or not the symbiosome was present); and 25% in M. verrucosa algae. In C. xamachana algae, photosynthesis increased. We conclude that the symbiosome is not essential for, yet does not block, the effects of HRF and PIF. 相似文献
18.
藻类和苔藓植物是荒漠植被演替过程中常见的两类先锋植物,同时也是生物结皮中生物量最大的2个类群。该文综述了近年来干旱半干旱荒漠地区生物结皮中藻类和苔藓两大类植物区系及其生态作用的研究进展,重点介绍藻类结皮、苔藓结皮的生态作用以及二者之间存在的生态学关系。在此基础上对荒漠生物结皮中藻类与苔藓植物的研究前景进行了展望,指出荒漠生物结皮中藻类与苔藓共生机理的探讨是未来的研究重点,这对进一步探明生物结皮中藻类和苔藓植物之间的相互作用,揭示它们的生态学关系具有重要的理论意义和实践价值。 相似文献
19.
Bruno P. Kremer 《Journal of phycology》1979,15(3):244-247
Several marine macroalgae representative of the Chlorophyceae, Rhodophyceae and Phaeophyceae were investigated for their potentials of photosynthesis and light independent (dark) carbon fixation. In addition, the activities of ribulose-1,5-bisphosphate carboxylase (RubP-C; EC 4.1.1.39) and of phosphoenolpyruvate carboxykinase (PEP-CK; EC 4.1.1.32) were studied. In contrast to the green and red algae investigated, all brown algae exhibited comparably high rates of dark fixation accounting for up to 20% of photosynthetic carbon uptake. These observations are confirmed by the activities of RubP-C and PEP-CK measured after extraction from different species and thallus regions. Dark fixed 14C was mainly recovered from aspartate, citrate, malate, glutamate, and alanine. Appreciable amounts of 14C were incorporated into insoluble (polymeric) constituents even after relatively short periods of dark fixation. 相似文献
20.
P Fay 《Applied microbiology》1976,31(3):376-379
Nitrogen-fixing activity declines first rapidly and then more gradually when Anabaenopsis circularis is transferred from light into dark conditions. The rate and duration of dark acetylene reduction (nitrogen fixation) depend upon conditions prevailing during the preceding light period. Factors (such as light intensity, CO2 concentration, and supply of glucose), which in the light affect photosynthesis and the accumulation of reserve carbon, have a profound effect on dark nitrogen fixation. Glucose greatly promotes nitrogen fixation in the light and supports prolonged nitrogenase activity in the dark. The results suggest that heterotrophic nitrogen fixation by blue-green algae in the field may be important both under light and dark conditions. 相似文献