The Arbuscules Formation Intensity Decreased in Mycorrhizal Alien Plants of Belarusian Polesia

Russian Journal of Ecology - Abstract—We tested a hypothesis about the different abilities of alien and native plants to form arbuscular mycorrhizae. The studies were carried out in the...     

The Edge Effect on the Herb–Dwarf Shrub Layer of Urbanized Southern Taiga Forests

Russian Journal of Ecology - We estimated when the edge effect appears in the herb–dwarf shrub layer of pine forests near Yekaterinburg (Central Urals; Southern Taiga subzone) on 14 transects...     

Changes in the ratio of plants with different mycorrhizal status in the course of pasture digression in the Southern Ural steppes

Trends in the proportions of plants differently interacting with mycorrhizal fungi in the course of pasture digression have been analyzed in the steppe zone of the Southern Urals. Estimates of species richness and abundance of plant groups with different mycorrhizal status have been obtained by comparing original data on the structure of phytocenoses with published data on the ability of plant species to form mycorrhizae. It has been shown that the proportions and abundance of obligate mycorrhizal species decrease significantly in the course of digression, with consequent increase in those of species less dependent on or independent of symbiosis with fungi, i.e., facultative mycorrhizal or obligate nonmycorrhizal plants.     

Influence of nonsymbiotic and symbiotic parameters of underground organs on the development of aboveground organs in <Emphasis Type=Italic>Pinus sylvestris</Emphasis> seedlings

A method is described for comparing the influences of nonsymbiotic and symbiotic parameters (accounted for by the plant itself and by the plant together with ectomycorrhizal fungi, respectively) of under-ground organs on the development of aboveground organs. The method has been used to analyze 4- to 12-month Scots pine seedlings from 26 habitats. The results show that 24 to 88% (on average, 54%) of total variation in the weight of aboveground organs is dependent on specific structural features of roots and mycorrhizae, with nonsymbiotic and symbiotic parameters of underground organs accounting for 5–73% (on average, 36%) and 3–45% (on average, 18%) of this variation.     

Factors of Richness of Urban Floras in the Ural–Volga Region

Original data on 14 urban floras in the Ural–Volga region have been analyzed to estimate the effect of the geographic location, topography, climate, size, and age of a city on the species richness of its flora. This parameter in different cities varied from 288 to 973 species, with the proportion of alien species varying from 21 to 41%. Factors of flora richness were estimated by multiple linear regression using principal component estimates obtained by factor analysis of 13 city characteristics as predictors. It has been confirmed that the richness of urban floras depends primarily on the city size, which accounts for greater proportions of variation in the number of native species (56%), the number of alien species (91%), and the total number of species (71%). In addition, variation in the number of native species is determined by terrain elevation (22%), increasing at higher elevations. The proportion of alien species in the urban flora does not depend on the size of the city and is negatively correlated with terrain elevation.     

Means for soil nutrient uptake in sedges with different ecological strategies

The prevalence of arbuscular mycorrhizas and nonsymbiotic modifications of absorbing organs (dauciform roots) has been studied in species of the genus Carex with competitive (C) and stress-tolerant (S) types of Grime-Ramenskii’s ecological strategies. The groups of C- and S-strategists do not differ in the ability to form mycorrhizas. Dauciform roots are more frequent in S-strategists, which accounts for a higher diversity of means for soil nutrient uptake in this group, compared to S-strategists.     

Anatomical Structure of Ectomycorrhiza in Abies sibirica Ledeb. and Picea obovata Ledeb. under Conditions of Forest Ecosystems Polluted with Emissions from Copper-Smelting Works

Changes in the anatomical characters of ectomycorrhiza in Siberian fir and Siberian spruce were studied in natural forests polluted with heavy metals (Cu, Zn, Cd, Pb, As, and Fe) and sulfur dioxide. As technogenic load increased, the total radius of mycorhiza terminals and plant roots included in them increased in the organic horizon and decreased in the mineral part of the soil. The absolute thickness of fungal mycorhiza caps and their relative contribution to the total volume of consuming organs increased under pollution. The observed responses were regarded as adaptive, aimed at compensating the adverse effects caused by technogenic pollution.     

Soil Moisture in Urbanized Habitats Invaded by Alien Acer negundo

Russian Journal of Ecology - We assessed the soil moisture in urbanized habitats dominated by alien (invasive) for Eurasia tree species Acer negundo. We supposed that the soil water content under...     

Specific features of root system morphology and mycorrhiza formation in scots pine seedlings from burned-out areas

Morphological parameters of the root system (the length of conducting roots and the number of absorbing roots) and the rate of its mycorrhization have been studied in one-year Scots pine seedlings from burned-out areas of cowberry-herb-green moss pine forest in the northern forest-steppe subzone of Western Siberia. The results show that the length of conducting roots in such seedlings increases, whereas the rate and density of mycorrhiza formation in absorbing roots decrease, compared to those in plants from unburned areas. The structure of underground organs in pine seedlings depends not only on fire intensity but also on the type of substrate in the burned-out area.     

Edge effects on pine stands in a large city

Manifestations of the edge effect on Scots pine (Pinus sylvestris L.) trees and stands were evaluated in natural southern taiga forests growing in a large industrial city (Yekaterinburg, Russia). For this purpose, 14 transects were laid out, each consisting of 6–10 circular 400-m² plots arranged in a line that extended for 140–260 m into the tree stand, perpendicular to its boundary. During transect surveys, 128 records were made of parameters characterizing the state of pine trees (height, diameter, defoliation level, needle age) and stands (density and timber volume). The boundaries differed in age, i.e., the time of formation (no more than 8 years and more than 20 years ago), and type (adjoining to motorways or wastelands). The edge effect manifested itself only near old boundaries and only for tree height (5 m lower near the boundary than deep in the forest) and for stand density and timber volume (25% lower), independently of the boundary type. Since the test parameters linearly increased with distance from the boundary, it was impossible to estimate the range of the edge effect.