Home – Home – Jornals – Advanced Search

The phenopool of natural populations is realized in the cultivated populations of Erysimum cheiranthoides L. Four morphological forms are distinguished: acro-, meso-, basiton and non-branching. The frequency of form occurrence varies in the populations of different years. The acroton form in the populations turned out to be the most stable one. With respect to the key features, the individuals of non-branching form turned out to be the most deviated from the typical acroton form. It was established on the basis of the analysis of correlation matrices and the construction of correlation pleiads that the longer does the cultivated population exist, the closer links are elaborated between the productive indices of the species.

The results of investigation of the daily rhythm of flowering of the selected population of Festuca arundinacea, native to Byelorussia, in the forest-steppe zone of West Siberia in 1988

The experimental data on the ecological features of moss habitat conditions in oligotrophic bogs are presented. The analysis of moss species composition and distribution on the microrelief elements was carried out. The density of moss stalks in different moss species mats was investigated. The vertical variability of air humidity in various layers of the moss mats was determined.

It is demonstrated that the forestland of suburban regions can be transformed under recreation load into the park-type forests. The latter are characterized by relative rarefaction of the forest canopy, low plenitude of the stand, almost absolute absence of natural renewal, and an increase in the fraction of forest-meadow and weed plants in the structure of herbage. However, in spite of noticeable anthropogenic impact, the soil of such forestlands keep in reserve substantial amount of viable diasporas representing active and potential soil banks. It is established that the soil of the forest phytocenosis under examination contains about 50 thousand /m² viable fern spores and more than 8 thousand /m² seeds of vascular plants. The major part of seeds present in soil is accumulated in soil bedding (73 %), while fern spores are accumulated in the mineral layer of soil.

The dynamics of changes in the volume of the arable lands and sowing areas of the Altai territory for XIX

Halogenated polyethers, pyrones, coumarins and flavones compose four comparatively small but interesting groups of natural compounds. Some of these compounds are antibiotics, toxins or biologically active substances. They have been found in microorganisms, e. g. cyanobacteria, fungi, plants, algae and in invertebrates. Structures of about 100 compounds have been considered, and data on their biological activity presented.

The initial stages of mechanical activation of the layered silicates with higher alcohols and hydroxyacids are investigated by means of IR spectroscopy and X-ray phase analysis. The formation of new materials is established; they are dispersed layered mechanocomposites formed due to neutralization of the active centres of basic character on the silicate surface by the protons of carboxylic groups of hydroxyacids or hydroxyl groups of higher alcohols. Hydroxyl groups of acid do not participate in the reaction with silicates. They are likely to form hydrogen bonds both with hydroxyl groups of silicates and with water molecules

The influence of mechanical activation conditions on the solubility of phosphate compounds of phosphorites from the Burenkhan deposit of Mongolia in 2 % solution of citric acid and in water medium was studied. It is established that the efficiency of planetary mill EI-2&x150 is considerably higher than that of vibration mill DRM-75T. As the time of activation is increased to 100 min, the assimilable phosphorus content of natural phosphates is heightened. For the vibration mill DRM-75T it is optimal to use as the milling body a steel cylindrical core with a mass of 1000 g. A mechanical activation of phosphorites was carried out with adsorbing additives in the form of lignosulphonates, zeolites and brown coals. The content of assimilable and water-soluble phosphates was determined depending on the composition and nature of additives. As the activation is continued when the amount of assimilable phosphorus is increased, the amount of water-soluble phosphorus is diminished. When lignin-containing additives are used, products with a high degree of phosphorus transition to 2 % solution of citric acid are formed with respect to activated phosphorites under equal treatment conditions. In this way, the possibility of obtaining organophosphorus fertilizers of prolonged action with various assimilability of phosphorus is estimated

The sequence and kinetics of solid-phase reactions that take place during mechanical alloying of the mixtures of Fe and B powders with the atomic ratios Fe(68)B(32) and Fe(85)B(15) were investigated by means of Mössbauer spectroscopy and X-ray diffraction. It was established that the initial stage of mechanical alloying includes the formation of nanostructural state in a-Fe particles and the formation of the Fe-B amorphous phase with the atomic fraction of boron up to 20 %. For other conditions being kept constant, a substantial difference in the kinetics of the initial stage in Fe-B and Fe-C systems was discovered. On the basis of indirect experimental data, it is assumed that the kinetics of the stage under consideration is determined by the size of B and C atoms.

Elemental and phase composition of the surface layers of two kinds of atmospheric aerosol sampled in Irkutsk, Listvyanka settlement and at the mountainous station Mondy was investigated by means of secondary ion mass spectrometry. The first kind includes the aerosol collected by pumping air through the filters, the second one includes aerosol particles captured while snow was falling, and afterwards collected on filters when pumping the melted snow. It was established that the action of water causes washing out Na, Ca and Ti from the surface layers and the formation of hydroaluminosilicates. Such an effect of water allows assuming that large range of scattering of the element concentrations in the surface layers of airborne aerosol particles is due to the action of atmospheric humidity, which depends on the residence time of aerosol in the atmosphere.