Specific features of the morphology and chemical properties of coarse-textured postagrogenic soils of the southern taiga,Kostroma oblast     

V. M. Telesnina  I. E. Vaganov  A. A. Karlsen  A. E. Ivanova  M. A. Zhukov  S. M. Lebedev 《Eurasian Soil Science》2016,49(1):102-115

The properties of loamy sandy postagrogenic soils in the course of their natural overgrowing were studied in the southeastern part of Kostroma oblast. Micromorphological indications of tillage were preserved in these soils at least 35–40 years after the cessation of their agricultural use. In the course of the soil overgrowing with forest vegetation, the bulk density of the upper part of the former plow horizon decreased, the pH and the ash content of the litter horizon somewhat lowered with a simultaneous increase in the acidity of the upper mineral horizon, especially at the beginning of the formation of the tree stand. In 5–7 years after the cessation of tillage, the former plow horizon was differentiated with respect to the organic carbon content. The total pool of organic carbon in the upper 30 cm increased. In the course of the further development, in the postagrogenic soil under the 90to 100-year-old forest, the organic carbon pool in this layer became lower. The soil of the young fallow (5–7 years) was characterized by the higher values of the microbial biomass in the upper mineral horizon in comparison with that in the plowed soil. In general, the microbial biomass in the studied postagrogenic ecosystems (the soils of the fields abandoned in 2005 and 2000 and the soil under the secondary 40-year-old forest) was lower than that in the soil of the subclimax 90to 100-year-old forest. The enzymatic activity of the soils tends to increase during the succession. The restoration of the invertase and, partly, catalase activities to the values typical of the soils under mature forests takes place in about 40 years.  相似文献   

The state of microbial complexes in soils of forest ecosystems after fires and defoliation of stands by gypsy moths     

A. V. Bogorodskaya  Yu. N. Baranchikov  G. A. Ivanova 《Eurasian Soil Science》2009,42(3):310-317

The state of microbial cenoses in the soils of forest ecosystems damaged by fires of different strengths and gypsy moth outbreaks (Central Siberia) was assessed by the intensity of the basal respiration, the content of carbon of the microbial biomass, and the microbial metabolic quotient. The degree of the disturbance of the microbial cenoses in the soils under pine forests after fires was higher than that in the soils under the forests defoliated by gypsy moths. The greatest changes of the microbial complexes were recorded after the fires of high and medium intensity. In the litters, the content of the microbial biomass, the intensity of basal respiration, and the microbial metabolic quotient value were restored on the fifth year after the fires, whereas in the upper (0–10 cm) soil layer, these parameters still differed from those in the control variant, especially after the highly intense fires. After the weak fires, the ecophysiological state of the microbial complexes was restored within two-three years.  相似文献   

Prevalence of obesity and overweight among urban adults in Bulgaria     

Ivanova L  Dimitrov P  Dellava J  Hoffman D 《Public health nutrition》2008,11(12):1407-1410

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A protocol to avoid precocious flowering of sunflower plantlets in vitro   总被引：1，自引：0，他引：1  

P. Ivanov    J. Encheva  I. Ivanova 《Plant Breeding》1998,117(6):582-584

Precocious flowering in in vitro plantelets of sunflower is one of the unfavourable phenomena when using tissue endure. In this sundy additional evidence is presented on precocious flowering of sunflower regenerats. Three day/night cycles (16/8h. 12/12h and 8/16h) and some modifications of media were investigated. Under standard conditions (16/8h day night. 25C) 62% of the plamlels formed flowers, while 55% formed flowers when grown in 12/12 h day. night at 20C and 31% when plantiets were grown under cultivation conditions of 8/16h day-night ai 20C. According to the results obtained, precocious flowering of sunflower plantlets in tesl tubes depends on culture conditions, nutrition medium and genotype. It was found that 20C and 8/16h diiy/nighl was the most favourable condition to reduce precocious flowering of sunflower planllels in the lest tuhe. Modified nutrition media can also help to reduce in vitro flowering.  相似文献   

Mycological complexes in Holocene and Late Pleistocene paleohorizons and in fragments of paleosols     

O. E. Marfenina  D. S. Sakharov  A. E. Ivanova  A. V. Rusakov 《Eurasian Soil Science》2009,42(4):432-439

Fragments of buried Late Pleistocene (30000-year-old) and Early Holocene (10000-year-old) paleosols contained viable complexes of microscopic fungi. The mycobiota of these paleosols represents a pool of fungal spores that is lower in number and species diversity as compared to that in the recent humus horizons and higher than that in the inclosing layers. The central part of the paleosol profiles is greatly enriched in microscopic fungi. In the intact humus horizons of the Late Holocene (1000–1200 years) paleosols, actively functioning fungal complexes are present. These horizons are characterized by their higher level of CO₂ emission. The buried horizons, as compared to the recent mineral ones, contain a greater fungal biomass (by several times) and have a higher species diversity of microscopic fungi (including fungi that are not isolated from the recent horizons). Nonsporulating forms are also present there as sterile mycelium. The seasonal dynamics of the species composition and biomass of the fungal complexes were more prominent and differed from those inherent to the surface soil horizons. In the buried humus horizons, the dynamics of the fungal biomass were mainly due to the changes in the content of spores. The data on the composition of the fungal complexes in the buried soils confirm (due to the presence of stenotopic species) the results of paleobotanic analyses of the past phytocenoses or do not contradict them.  相似文献   

Transformation of microbial cenoses in soils of light coniferous forests caused by cuttings and fires in the Lower Angara River basin     

A. V. Bogorodskaya  E. A. Kukavskaya  G. A. Ivanova 《Eurasian Soil Science》2014,47(3):194-202

The influence of surface fires and cutting on the quantitative and functional parameters of microbial cenoses in the soils of light coniferous forests in the Lower Angara River basin was studied. In the litters of soddy-podzolic soils under pine forests, the microbial biomass was 4080–4700 μg C/g; the basal respiration was 17.00–20.32 μg C-CO₂/g/h; and the qCO₂, 4.17–4.33 μg C-CO₂/mg C_mic/h. In the humus-accumulative horizon, these values were 880–1160 μg C/g, 2.48–4.12 μg C-CO₂/g/h, and 2.83–3.55 C-CO₂/mg C_mic/h, respectively. In the litter of the one-year-old felled area, the content of microbial biomass carbon was by two times lower; in the litter of burned plots, it was by 60–70% lower than in the litter of the control area. The intensity of the microbial respiration did not change proportionally to the microbial biomass content, which resulted in an imbalance between the processes of the organic matter mineralization-immobilization towards a release of CO₂ as evidenced by the increase of the qCO₂ values by 2–4 times. In the five-year-old felled area, at the stage of restoring the herbaceous vegetation, a tendency towards the stabilization of the destructive microbiological processes was revealed. In the felled areas, the high number of heterotrophic microorganisms, the reduced oligotrophy of the soil organic horizons, and the more intense microbiological mineralization of the organic matter were observed. The surface fires in the felled areas and forests significantly affected the structure and the number of ecological-trophic groups of microorganisms in the litters, the humus-accumulative horizons, and in the upper mineral soil layers. The maximal structural and functional disturbance in the soil microbial complex was found in the logged areas affected by fires.  相似文献   

Atlantic meridional overturning circulation during the Last Glacial Maximum     

Lynch-Stieglitz J  Adkins JF  Curry WB  Dokken T  Hall IR  Herguera JC  Hirschi JJ  Ivanova EV  Kissel C  Marchal O  Marchitto TM  McCave IN  McManus JF  Mulitza S  Ninnemann U  Peeters F  Yu EF  Zahn R 《Science (New York, N.Y.)》2007,316(5821):66-69

The circulation of the deep Atlantic Ocean during the height of the last ice age appears to have been quite different from today. We review observations implying that Atlantic meridional overturning circulation during the Last Glacial Maximum was neither extremely sluggish nor an enhanced version of present-day circulation. The distribution of the decay products of uranium in sediments is consistent with a residence time for deep waters in the Atlantic only slightly greater than today. However, evidence from multiple water-mass tracers supports a different distribution of deep-water properties, including density, which is dynamically linked to circulation.  相似文献   

The genetic program of hematopoietic stem cells     

Phillips RL  Ernst RE  Brunk B  Ivanova N  Mahan MA  Deanehan JK  Moore KA  Overton GC  Lemischka IR 《Science (New York, N.Y.)》2000,288(5471):1635-1640

Blood cell production originates from a rare population of multipotent, self-renewing stem cells. A genome-wide gene expression analysis was performed in order to define regulatory pathways in stem cells as well as their global genetic program. Subtracted complementary DNA libraries from highly purified murine fetal liver stem cells were analyzed with bioinformatic and array hybridization strategies. A large percentage of the several thousand gene products that have been characterized correspond to previously undescribed molecules with properties suggestive of regulatory functions. The complete data, available in a biological process-oriented database, represent the molecular phenotype of the hematopoietic stem cell.  相似文献   

Comparative economic characteristics of methods of disinfecting wool in brucellosis     

V I Ivanova  Iu I Tarakanov  S P Ponomarev  A I D'iachenko 《Veterinariia》1969,46(3):103-105

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An electron microscopic study of strains of the virus of classic fowl plague     

L G Astapovich  G A Ivanova  S B Logginov 《Veterinariia》1968,45(9):24-26

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