Transformation and Reconstitution of Vegetation in the Pre-Baikal

The work represents the results of perennial studies of the structural-dynamic organization of the phytocoenoses, which are subjected during a long period to anthropogenic impact in different, for geographical conditions, areas of western and south-eastern Pre-Baikal. The composition of phytocoenoses, which form at cuttings of forests of different composition and typology is found out. The following parameters are determined: species composition, synfolial differentiation and dominant species of the soil cover reflecting the dynamics of reconstitutional stages of polydominant light-coniferous forests of Pre-Baikalian type. We noticed the peculiarities of transformation and reconstitution of the coenoses, which during a long period are used for haying and pasturage formed on the site of earlier cut timber stands at the boundary with the extrazonal steppe. During last decades, a gradual forestation of these territories is observed, the steppe plants species in the soil cover are replaced by forest species characteristic for the light-coniferous taiga. On the site of cuttings of dark-coniferous taiga in the first half of the last century in the southern part of Pre-Baikal, forests form with dominance of more hydrophilic trees species in undergrowth and young growth – fir and spruce replace cedar everywhere. This is probably due to secular forests dynamics with replacement of forest forming trees species on the background of climate changes during last decades. There are as well changes in the species composition of plants on the soil cover of forming dark-coniferous taiga.

EVALUATION OF THE BIOLOGICAL ACTIVITY OF THE RHIZOSPHERE SORGHUM BICOLOR UNDER THE INFLUENCE OF MICROBIAL PREPARATIONS USING NO-TILL TECHNOLOGY IN THE CRIMEAN STEPPE

In steppe plants regularly lack of moisture and it affects the biochemical functions of their development. The aim of this research was to study the enzymatic activity of the Sorghum bicolor (L.) Moench rhizosphere grown by no-till technology under the influence of introduced microorganisms under conditions of moisture deficit. The growing season of Sorghum bicolor during the research period (2018–2020) was characterized by high temperature and arid conditions. The lack of precipitation reached 68.5 % in comparison with the average long-term indicators. It was revealed that the influence of the weather conditions of the year and the complex of microbial preparations (CMP) on the changes in the enzymatic activity of the S. bicolor rhizosphere was at the level of p≤0.05. IIBS (integral indicator of biological state) was calculated based on the level of activity of various enzymes in the soil. The value of IIBS with CMP is close to 80 %. It shows that no-till farming using CMP contributes to physiological stability of the rhizosphere. At the same time, the IBPS annually decreased by 61.1–92.8 % in the control variant without pre-sowing treatment of seeds with CMP, which indicates a slowdown of biological processes. The results of the studies proved that the adaptation of sorghum plants to the effects of abiotic environmental conditions is carried out by regulating the enzymatic activity of the rhizosphere by introducing microorganisms. Consequently, the use of microbial preparations is advisable for the cultivation of S. bicolor by no-till technology in steppe zone of Crimea.

Coal mining in Kuzbass and new technologies for revegetation of dumps

During the period of coal mining in Kuzbass, about 9 billion tons of coal were mined, which is 16% of all in-place reserves of coal in Kuzbass. In 2020, coal production amounted to 220.7 million tons, including 164.4 million tons of open pit mining, which is 74% of the total. The negative side of an increase in the share of open pit coal mining is an increase in the area of disturbed lands, which currently reaches 150 thousand hectares. To restore the biological diversity of dumps, a nature-like technology has been developed for revegetation of dumps, which consists in applying a 15 cm thick loam layer to the dump and introducing a grass seed mixture containing seeds of steppe plants. For six years, a stable, self-perpetuating permanent nature-like community is formed, numbering 30-40 species of steppe plants.

Seed Germination in Alpine Meadow Steppe Plants from Central Tibet in Response to Experimental Warming

Clarifying the effects of climate warming on seed germination is critical for predicting plant community assembly and species renewal, especially in alpine grassland ecosystems where warming is occurring faster than in other biomes globally. We collected matured seeds of 19 common species from a typical alpine meadow steppe community in Central Tibet. Seeds were germinated in three incubators with manipulated day-night temperatures to impose three treatments: (1) theoretically optimal values of 25/15 °C, (2) temperatures observed in the field (control), and (3) a warming of 3 °C above the observed temperatures. We calculated seed germination percentage (SGP) and mean germination time (MGT) per species at different treatments. Our results showed that SGPs of Stipa capillacea, Kobresia macrantha, Potentilla saundersiana, Saussurea tibetica, Pedicularis kansuensis, and Androsace graminifolia were higher under the warming treatment than under control. Among them, the MGTs of S. capillacea, K. macrantha, and And. graminifolia were significantly shortened, while the MGT of Pe. kansuensis was significantly lengthened by warming of 3 °C. Significant decreases in MGT induced by warming were only observed for Festuca coelestis and Anaphalis xylorhiza. Additionally, the treatment with theoretically optimal temperatures restrained germination of Stipa purpurea, S. capillacea, F. coelestis, and Sa. tibetica seeds but promoted germination of K. macrantha, Astragalus strictus, P. saundersiana, Potentilla bifurca, Pe. kansuensis, Swertia tetraptera, Pleurospermum hedinii, and And. Graminifolia seeds, when compared with the control and warming treatments. Therefore, the response of seed germination to warming differs among alpine species, implying that future warming could result in significant changes in community assembly of alpine grasslands on the Tibetan Plateau.

In vitro effect of crude extracts from eight Algerian steppe plants on mycelial growth and sporulation of Ascochyta pisi Lib.

Se ha estudiado el efecto de extractos crudos de ocho plantas, que crecen en la estepa argelina, contra Ascochyta pisi Lib., uno de los miembros del complejo Ascochyta que causa la antracnosis del guisante, con el objetivo de sustituirlos por fungicidas químicos con reconocida nocividad para el medio ambiente y la salud pública. Con este propósito, se realizó una prueba de control biológico in vitro del crecimiento y la esporulación de A. pisi, agregando extractos de plantas crudas o sus sub-fracciones a su medio de cultivo. Al final de este ensayo, encontramos que los extractos de Artemisia alba Turra, Lycium arabicum Schweinf. Ex Boiss. y Peganum harmala Linn. registraron las mejores tasas de inhibición del crecimiento de patógenos, mientras que Artemisia campestris L. es más efectiva contra su esporulación. This work consists of studying the effect of crude extracts of eight plants growing in the Algerian steppe against Ascochyta pisi Lib., one of the members of the Ascochyta complex causing the Ascochyta blight of pea, with the aim of substituting them for chemical fungicides recognized for their harmfulness to the environment and public health. For this purpose, an in-vitro biocontrol test of the growth and sporulation of A. pisi was achieved by adding to its cultural medium a crude plant extracts or their sub-fractions. At the end of this trial, we found that the extracts of Artemisia alba Turra, Lycium arabicum Schweinf. Ex Boiss. and Peganum harmala Linn. recorded the best growth inhibition rates of pathogenic whereas, Artemisia campestris L. is more effective against its sporulation.