Effect of bacterization with Aeromonas media GS4 and Pseudomonas extremorientalis PhS1 on wheat seedlings under different abiotic conditions

We studied the effect of soft wheat seed treatment (Triticum aestivum L.) with two bacterial strains (Aeromonas media GS4 and Pseudomonas extremorientalis PhS1) isolated from earthworm coprolites on the growth and development of wheat seedlings in a 12-day laboratory experiment, as well as on root rot disease and the activity of guaiacol-dependant peroxidase under optimal conditions and abiotic stress (elevated and low temperatures and moisture content). We established that growing nonbacterized wheat plants under stress abiotic conditions reduced the height of plants compared to growing under optimal abiotic conditions, and seed bacterization with P. extremorientalis PhS1 strain increased wheat plant height (by 9-15%) under stress abiotic conditions compared to the nonbacterized plants. Bacterization with both strains decreased infestation of wheat seedlings (2.5-4 times) by root rots under unfavorable abiotic conditions compared to nonbacterized plants. In addition, under optimal and arid conditions, bacterization with P. extremorientalis PhS1 strain was the most effective, and under humid conditions it was bacterization with A. media GS4 strain. We showed that the activity of guaiacol-dependant peroxidase correlates with the development of plant resistance to abiotic stress. In our experiments, plant bacterization resulted in a 2-fold increase in peroxidase activity both in leaves and roots of wheat plants compared to the nonbacterized plants. As the result, the ability of bacteria to activate peroxidase can serve as an information indicator of strengthening protective mechanisms of plants during bacterization

The mathematical simulation of the temperature fields of building envelopes under permanent frozen soil conditions

The physical-mathematical model of the thermal state of the aired technical underground taking into account the air exchange and design features of construction under permanent frozen soil conditions has been suggested. The computational scheme of the temperature fields prediction of building envelopes of projected buildings and soil under and nearby buildings has been developed. The numerical simulation of the temperature fields of building envelopes changes was conducted during a year. The results of the numerical simulation showed that the heat coming from the technical undergrounds and through the walls does not influence the temperature field of the soil neither under a building nor at a distance from it

Prospects for the peat using as the basis of the soil-like substrate in mini-ecosystems modelling

Global urbanization is causing a constant decline in arable land as cities and associated industrial zones are "attacking" adjacent agricultural areas. One of the promising ways to solve the problem of increasing food production for the constantly growing population of the planet against the background of rapidly decreasing land resources is the development of fundamentally new alternative methods for the production of crop products, including in greenhouses. The fundamental basis for technological optimization of plant cultivation parameters and the output of the productive process of a particular crop to the maximum of its genetic capacities can be the development of artificial mini-ecosystems based on the reproduction of nature-like processes, implying the balance and combination in one volume of the processes of plant production and reduction of organic waste, initiated directly in the zone of the rhizosphere of plants due to the introduction of technological earthworms into the reduction zone. According to the results of model studies presented in this article, peat is an acceptable basis for the substrate of the root block of a mini-ecosystem, and the introduction of earthworms Eisenia fetida Sav. into the reduction zone does not have a negative effect on lettuce plants, provided that it is used as an energy substrate for cattle manure worms in quantities not exceeding 10 - 20% of the total volume of the substrate

Pseudomonads associated with soil lumbricides as promising agents in root rot biocontrol for spring grain crops

Currently, crop yields can be increased by high farming standards which include environmentally friendly use of chemical fertilizers and pesticides, as well as their replacement by bioformulations having similar activity. That is why both search for new promising species, strains and isolates of bacterial antagonists for their potential use as biocontrol agents, and study of antifungal activity mechanisms, particularly the relationship between the activity in model tests and in agrocenoses, are relevant. The aim of this study was to estimate bacterial isolates from redworm coprolites as potential bioactive agents to control phytopathogenic fungi causing root rot of crops. The experiments were conducted in 2013-2015. In the preliminary laboratory screening for fungistatic and growth-promoting activity we selected two strains, Pseudomonas sp. GS4 and Pseudomonas sp. PhS1, and assessed their ability to decrease the growth rate of fungal colonies in Petri dish test on nutrient agar medium and to reduce seed infestation of soft wheat (Triticum aestivum L., Irgin cultivar) in sterile paper roll test. Seeds soaked in distilled water served as control. As a standard, we used seed treatment with a chemical fungicide Dividend® Star («Syngenta AG», Switzerland) (30 g/l difenoconazole, 6.3 g/l cyproconazole) at recommended rates. In field tests, we recorded root rots in soft wheat Irgin cultivar plants and in barley (Hordeum vulgare L.) Acha cultivar plants during tillering and beginning of blooming. The laboratory tests showed a statistically significant (р < 0.05) 1.5-2.5-fold decrease in the growth rate of phytopathogenic fungi Fusarium oxysporum, Bipolaris sorokiniana and Alternaria spp. as compared to control. In all experiments with bacterization, there was a 53-76 % decrease (р < 0.05) in total seed infestation by pathogens as compared to non-bacterized plants. The effect of the bacteria in planta was assessed in small model systems. The obtained data show a statistically significant (р < 0.05) reduction in the root rot disease incidence in bacterization with Pseudomonassp. GS4 (by 33-37 %) and Pseudomonas sp. PhS1 (by 57-60 %). Root rot disease severity decreases 2.1-2.4-fold and 3.3-3.5-fold, respectively. In 2015, we revealed a tendency towards a 19-70 % increase in the total number of rhizosphere microorganisms at the beginning of plant blooming depending on the crop and type of bacterization. The number of hosphate-mobilizing bacteria in the rhizosphere under bacterization was, on average, 5.5-7.2-fold higher in wheat and 2.1-3.2-fold higher in barley than that without bacterization. Our results of root rot field study in the 2013-2015 showed the efficacy of both monocultures and complex bacterization which provided a decrease in wheat and barley root rot disease severity by 6.5-57.6 % and 18.6-50.0 %, respectively, depending on the bacterial culture and the weather conditions. The maximum biological efficacy of the isolates is noted at the beginning of blooming

Effect of seed bacterization on peroxidase activity in wheat plants when infected with Bipolaris sorokiniana under high temperature and low moisture

The ability of rhizosphere bacteria to induce systemic resistance in plants has been widely described in the literature. Various products of rhizobacteria act as signalling molecules, developing stress-like reactions in the plant. At the same time, the accumulation of peroxidase and other reactive oxygen species in the cell plays a major role, and is one of the most important plant defence mechanisms in response to various stressors. Peroxidase is a polyfunctional enzyme involved in both the generation and the utilization of hydrogen peroxide, and its activity in cells is related to plant resistance to phytopathogens and adverse environmental conditions. We measured the levels of free and weakly bound guaiacol-dependent peroxidase in the roots and leaves of wheat plants both inoculated with Pseudomonas extremorientalis PhS1 and Aeromonas media GS4 and uninoculated, under conditions of high temperatures and low humidity, with and without the phytopathogen Bipolaris sorokiniana. Following inoculation, a 1.4–5.2-fold increase in the severity of plants affected with the phytopathogen was observed. Seed bacterization decreased the number of damaged plants both with and without the phytopathogen by 1.2–2.4 and 3.2–4.7 times, respectively. Seed bacterization increased peroxidase activity in leaves and roots with and without the phytopathogen. Correlation analysis showed a statistically significant (P < 0.05) relationship between the increased activity of peroxidase in wheat leaves and roots and the reduced number of affected plants. The strongest relationship was observed between the enzyme activity in wheat roots and a decrease in the disease severity with the phytopathogen

The mathematical simulation of the temperature fields of building envelopes under permanent frozen soil conditions

The physical-mathematical model of the thermal state of the aired technical underground taking into account the air exchange and design features of construction under permanent frozen soil conditions has been suggested. The computational scheme of the temperature fields prediction of building envelopes of projected buildings and soil under and nearby buildings has been developed. The numerical simulation of the temperature fields of building envelopes changes was conducted during a year. The results of the numerical simulation showed that the heat coming from the technical undergrounds and through the walls does not influence the temperature field of the soil neither under a building nor at a distance from it

Utilizing heavy metal-laden water hyacinth biomass in vermicomposting

We studied the efficiency of water treatment by water hyacinth (Eichhornia crassipes) from heavy metals (Zn

Utilizing heavy metal-laden water hyacinth biomass in vermicomposting

We studied the efficiency of water treatment by water hyacinth (Eichhornia crassipes) from heavy metals (Zn