New data on the bacterial flora of fluvial waters of the upper and middle Ob basin obtained in the course of comprehensive ecogeochemical studies in 1990-1998 are described. Some important peculiarities of microbiological composition of waters have been established: 1) in the quantitative composition of chemotrophic bacteria prevalent are microorganisms adapted to inhabiting a milieu with a lowered content of complicated organic compounds; 2) in fluvial waters, bacteria oxidizing hydrocarbons and phenols are ubiquitously spread; 3) among the rivers studied, conspicuous is the Tom, the biological composition of whose waters witnesses to the greatest anthropogenous load on aquatic ecosystems in the region under consideration. The anthropogenous influence is manifested in a short-term increase of various groups of microorganisms. In some cases, the increas in the numbers of bacteria is due to natural factors among which of great importance is the the enhancement of surface washing-off from the water taking areas during floods. P. 173-180
Possibilities of cartographic method of studying the vegetation of ecologically hazardous territories of various nature in the Baikal region are considered. Development of cartographic models of conditions of genesis of plant communities for concrete types of ecological risks (evolutionary, dynamic, anthropogenous, and their combinations) will make it possible to obtain more objective information about the modern state of phytocenoses in concrete territories. It is supposed that drawing up series of situational geobotanic maps will permit following up timely the tendencies in plants under the conditions of formation of some or other type of ecological risk. P. 181-184
On the basis of retrospective methods of reconstruction of sexual reproduction and shoot and tree growth of Siberian cedar, a comparison of their time course has been made. It is demonstrated that reproduction chonologies, especially in branches of second order, are more sensitive to the influence of external factors than the growth branches are. They differ also in the coefficient of determination and in the autocorrelation function of first order. Differences in the structure of cyclicity and of the trend of chronological changes in the growth and reproduction processes have been found.
Some bioecological peculiarities of development of generative organs of transitional physiological form of black poplar (Populus nigra L.) in protective plantations in the south of West Siberia are considered. P. 191-198
The concept of "formation of burned-out forests" is introduced. A method of its estimation is proposed. A model of burned-out forest formation for light-coniferous forests of the Ust-Ilim industrial complex has been developed. The model ranks the plantations of forest taxation plots according to their fire resistance. P. 199-202
The studies are dedicated to estimation of trophical conditions in the forests of permafrost zone of Middle Siberia. In the root-abiding layer of larch stands, an insignificant amount of total nitrogen, with the maximum in stands with a powerful development of the soil cover and litter bedding has been found. However, the proportion of its accessible forms, especially in the soil, is very large. Therein, dominant among the accessible fractions are easily and moderately hydrolyseable ones, in which free amino acids are abundantly present. The mineral nitrogen content of permafrost soils, and especially in the mineral layer, is insignificant. Organogenic horizons of larch stands where the main reserves of absorbing roots are concentrated are the main source of nitrogen for plant communities of this region, and here competition for nitrition elements arise between them at certain succession stages. P. 203-212
Results of studies of wood-destroying fungi of the order Aphyllophorales (Basidiomycetes) in the territory of the Salair mountain range and Mountainous Shoria are presented. Peculiarities of diffusion and existence of these fungi in nature, and the problems and perspectives associated with their study are considered. P. 213-220
Analysis of germination of seeds of 117 rare and disappearing species of Siberian flora at definite temperature conditions has permitted distinguishing three ecological groups: the thermophile group - the most numereous one (64 %) whose seeds can germinate at high positive temperatures 0f 18-30 oC; thermopsychrophile (intermediate) group of species (13 %) - a part of seeds germinate at high positive temperatures, and the major part can germinate after exposure to low positive temperatures (0-5 oC), and the third, psychrophile group (24 %) whose seeds germinate only at low positive temperatures or after an exposure to these. Characteristic of seeds of many species is a wide range of normal reaction to temperature and illumination conditions, which is determined by their origin and complicated history of genesis of Siberian flora. P. 221-236
The pattern of distribution of linden across the areal has been studied. The causes contributing to survival of the root system and the degree of resistance to adverse environmental factors have been elucidated. P. 237-242
The dependence of the time of going through definite stages of nodulation process on the roots of pea plants infected by bacteria Rhizobium laguminosarum upon the surrounding temperature (optimal or lowered) and the substrate on which the plants had been grown (sand and aquatic medium) has been studied. It is demonstrated that low temperature and the hydroculture conditions retard the nodulation process, especially the 1-st stage including the period from the moment of infection to emergence of the first nodule germs. Therein, a more effective factor is the low temperature. It is established that under all the changes of germination conditions at all the nodulation stages studied, changes in the content of "soluble" (extractable with ethyl acetatec and butanol) and "insoluble" (attached to cellular structures) phenolic compounds (PC) take place. However, the general rules in the changes of PC content for environmental conditions created by us and inhibiting the nodulation process have not been elucidated. P. 243-248
