Initial Stages Of Plant Development Research Articles

Analysis of the endophytic microbiota of roots and culms of two commercial sugarcane cultivars inoculated with a synthetic microbial community

The adoption of bioinputs in agriculture has aroused great interest in recent years and, in this scenario, the inoculation of crops with synthetic microbial communities (SynComs) has shown to be promising. In sugarcane crop, inoculation with nitrogen-fixing bacteria (NFB) in consortium with arbuscular mycorrhizal fungi (AMF) has shown positive results on plant development and nutrition. However, considering that the microbiota plays a fundamental role in the growth and health of the host plant, especially the endophytes, which are closely associated, few studies have explored the effects of SynCom inoculation on the endophytic microbiota of sugarcane. This study aimed to evaluate the impact of SynCom inoculation on the structure of the endophytic microbiota of sugarcane. The results of the analyses revealed that the microbiota diversity remained unchanged due to the inoculation treatment, while differences in microbial communities were found between the two evaluated commercial cultivars, RB867515 and RB92579, and between the two plant organs, roots and culms, under field conditions at the end of the first crop growth cycle (~360 days). Furthermore, microbes specifically detected in roots or culms present potential valuable applications in sugarcane cultivation in the future. Altogether, our data support that the inoculated microorganisms exerted their beneficial effects during the initial stages of plant development, which opens up space for new research with SynComs in these primordial stages of cane cropping.

Features of the development of the primary roots of wheat seedlings after the removal of abiotic electromagnetic stress

The study considers the features of the development of the primary roots of spring wheat seedlings after pre-sowing exposure to a UHF EMF under conditions of pre-moistening of seeds. The object of the experiment was the seeds of soft spring wheat (Triticum aestivum L.) varieties Novosibirskaya 31, Alyoshina, Trizo, Iren, Pamyati Aphrodite, and Altayskaya 70. In the experimental variants, the duration of the microwave EMF (0, 5, 10, 15 s) and the seed moisture (15, 20, 25, 30%) were combined. The influence of the UHF EMF on the intensity of the development of the primary roots of spring wheat seedlings was significant. For example, one of the varieties (Triso) shows a slight decrease in the intensity of growth processes during a fifteen-second treatment. The decrease in root mass was 18.18% (moisture content 15%) and 2.20 times (moisture content 20%) compared to the control. Wheat variety Iren had a decrease in root weight relative to the untreated variant by 2.59 times (at a moisture content of 15%) and 7.33 times (at a moisture content of 20%). The features of root growth at the initial stages of plant development were variety-specific and also depended on the modes of microwave processing. An unfavorable variant of microwave irradiation was a combination of the duration of exposure of 15 s and the preliminary humidity of the processed grain of 30%. The variant of EMF exposure for 5 s stimulated growth processes in germinating grains expressed in a relative increase in the number of roots and their wet weight compared to the control. The variant of exposure to an EMF for 5 s stimulates growth processes in germinating grains, which is expressed in a relative increase in the number of roots compared to the control. This difference is 13.47% for the Novosibirskaya 31 variety, for the Trizo variety – 14.99%, Iren – 12.44%, Pamyati Aphrodite – 8.97%, and Alyoshina – 13.93% on average. According to the totality of the studied indicators, two varieties of spring wheat were distinguished: the variety of Pamyati Aphrodite as the most stable and the variety Alyoshina as the most plastic. The results obtained can be used in practical plant growing to increase the adaptive capacity of plants and, consequently, increase productivity. A well-developed root system will allow wheat to withstand adverse weather conditions and form a higher grain productivity.

Evaluation of sainfoin (Onobrychis) in the source material nursery according to new selection criteria at the initial stages of organogenesis

Topicality. The implementation of new selection criteria will solve the problem of forming the sainfoin resistance to extreme hydrothermal conditions and insufficient moisture. Sainfoin adult plants have a high level of drought resistance, unlike its seedlings, which are sensitive to the air and soil moisture deficit. Therefore, the ability of seedlings to adapt to unfavorable moisture conditions has a positive effect on the further development of plants and the formation of their productivity elements. Purpose. To evaluate the principles of new selection criteria for sainfoin biotypes in the breeding process at the initial stages of organogenesis. Materials and methods. The laying of the nursery of the initial material was carried out using new elements of the technology of growing sainfoin, namely summer sowing. Seeds of samples obtained by positive selection from breeding, seed crops, collections of other scientific institutions and local wild populations of sainfoin were sown. The new criteria for selecting sainfoin biotypes are based on an assessment of the intensity of root system development and the calculation of the coefficient of negative drought effect. General scientific research methods are as follows: field, laboratory, measuring-weight, calculation-comparative, mathematical statistics. Results. In the source material nursery of the first year of life, 113 families (45.7 % of the total) formed a root system with a volume of more than 6.5 cm³ within 2.5 months after sowing. Only 77 families (31.2 % of the total number) had a drought impact coefficient of 0.46 or less, i.e., they are suitable for breeding highly productive populations in arid climatic conditions. Sowing seeds of families selected according to the new criteria ensured that number of families with a strong root system (more than 6.5 cm³) increased from 42.2 % to 57.2 % in the next generation, increased plant survival during the first year of life from 63.2 % to 87.2–95.0 %, in winter – from 83.3 % to 90.4–94.8 %, and resistance to fungal diseases from 81 % to 90–95 %. In the nursery of the source material, the share of families with the highest number of shoots per plant (> 27 pcs) and height (> 20 cm) was 27.4 % and 26.6 %, respectively, and was equal to the number of families with a root volume of more than 7.5 cm³ – 27.4 %. Conclusions. According to the results of determining the root volume of sainfoin plants and calculating the coefficient of negative effect of drought, the most productive breeding samples can be selected in the first years of life when using summer sowing with freshly harvested seeds. The selection of breeding material based on new criteria made it possible to identify families with high adaptive potential at the initial stages of plant development in arid conditions of the eastern part of the Northern Steppe of Ukraine. Key words: breeding, sainfoin, root volume of plant, coefficient of negative drought impact, condition of plants

Effect of late nitrogen nutrition on formation of harvest elements, grain yield, and quality indicators of winter wheat

It is known that almost 50% of winter wheat harvest is due to mineral fertilizers. Among mineral fertilizers, nitrogenous fertilizers are of special importance. The plant’s response to nitrogen fertilizers starts from the initial stages of plant development and continues until the ripening stage. Nitrogen is involved in all physiological processes in the plant. Nitrogen fertilizers differ from other types of macro fertilizers in their mobility. These fertilizers have a quick effect on the plant and are easily absorbed by the plant. There are different opinions about winter wheat fertilization. Some experts believe that the annual rate of nitrogen fertilizers should be applied in the early stages of development, in early spring. Other authors state that nitrogen fertilization is necessary two or three times during the season. In the experiment, a relatively low indicator of grain yield was observed in the control option of 35 q/ha, and the highest indicator was 72 q/ha in the triple-fed option. In the experiment, additional nitrogen fertilization provided an additional grain yield of 21-37 q/ha of winter wheat. The highest results for all quality indicators of grain were recorded in conditions where nitrogen fertilizer was applied at the rate of 80+80+40 kg/ha three times during the growing season. In this variant, the grain transparency was 90%, the protein content was 14.3%, and the gluten content was 30.3%.

Diaspore dispersal season influences root growth and seed traits, but not germination responses, of sympatric Piper species in a seasonal forest.

Seeds may differ in terms of dormancy, longevity, sensitivity to desiccation and dry mass, according to the timing (dry season/rainy season) of diaspore dispersal. In addition, seasonal variations in temperature and water availability can act as signals of the season during seed development, influencing germination responses and root growth. We evaluated the effects of temperature variations and water availability on germination parameters, root growth and seed traits of four coexisting Piper species in seasonal vegetation that differed in diaspore dispersal timing. Eight temperature treatments (15, 20, 23, 25, 28, 30, 35 °C, and alternate 30 °C-20 °C) and four induced water potentials (0, -0.3, -0.6 and -1.2 MPa) were used. The parameters germination onset, germination percentage (G%), mean germination time (MGT), root elongation, seed longevity during ex situ storage and dry mass of seeds were evaluated. Germination responses observed were independent of the diaspore dispersal timing, such as variations in germination onset, G% and MGT, both in temperature and water availability treatments. In contrast, root elongation, longevity and dry mass of seeds varied according to the time of diaspore dispersal. Our results corroborate the hypothesis that the timing of diaspore dispersal is an important factor in controlling the initial development of seedlings in seasonal vegetation, but not in germination responses. The predominance of negative effects of temperature increases and water deficit on root growth shows that the initial stages of plant development can be strongly impacted by these environmental factors.

Inoculation of Herbaspirillum seropedicae strain SmR1 increases biomass in maize roots DKB 390 variety in the early stages of plant development.

Herbaspirillum seropedicae is a plant growth-promoting bacteria isolated from diverse plant species. In this work, the main objective was to investigate the efficiency of H. seropedicae strain SmR1 in colonizing and increasing maize growth (DKB 390 variety) in the early stages of development under greenhouse conditions. Inoculation with H. seropedicae resulted in 19.43 % (regarding High and Low N controls) and 10.51% (regarding Low N control) in mean of increase of root biomass, for 1st and 2nd greenhouse experiments, respectively, mainly in the initial stages of plant development, at 21 days after emergence (DAE). Quantification of H. seropedicae in roots and leaves was performed by quantitative PCR. H. seropedicae was detected only in maize inoculated roots by qPCR, and a slight decrease in DNA copy number g-1 of fresh root weight was observed from 7 to 21 DAE, suggesting that there was initial effective colonization on maize plants. H. seropedicae strain SmR1 efficiently increased maize root biomass exhibiting its potential to be used as inoculant in agricultures systems.

Evaluation of Phenolic Root Exudates as Stimulants of Saptrophic Fungi in the Rhizosphere.

The rhizosphere microbial community of crop plants in intensively managed arable soils is strongly dominated by bacteria, especially in the initial stages of plant development. In order to establish more diverse and balanced rhizosphere microbiomes, as seen for wild plants, crop variety selection could be based on their ability to promote growth of saprotrophic fungi in the rhizosphere. We hypothesized that this can be achieved by increasing the exudation of phenolic acids, as generally higher fungal abundance is observed in environments with phenolic-rich inputs, such as exudates of older plants and litter leachates. To test this, a rhizosphere simulation microcosm was designed to establish gradual diffusion of root exudate metabolites from sterile sand into arable soil. With this system, we tested the fungus-stimulating effect of eight phenolic acids alone or in combination with primary root metabolites. Ergosterol-based fungal biomass measurements revealed that most phenolic acids did not increase fungal abundance in the arable soil layer. These results were supported by comparison of fungal biomass in the rhizosphere of wild type Arabidopsis thaliana plants and mutants with altered phenolic acid metabolism. Salicylic acid was the only phenolic acid that stimulated a higher fungal biomass in the arable soil layer of microcosms, but only when combined with a background of primary root metabolites. However, such effect on rhizosphere fungi was not confirmed for a salicylic acid-impaired A. thaliana mutant. For three phenolic acid treatments (chlorogenic acid, salicylic acid, vanillic acid) fungal and bacterial community compositions were analyzed using amplicon sequencing. Despite having little effect on fungal biomass, phenolic acids combined with primary metabolites promoted a higher relative abundance of soil-borne fungi with the ability to invade plant roots (Fusarium, Trichoderma and Fusicolla spp.) in the simulated rhizosphere. Bacterial community composition was also affected by these phenolic acids. Although this study indicates that phenolic acids do not increase fungal biomass in the rhizosphere, we highlight a potential role of phenolic acids as attractants for root-colonizing fungi.

ЭФФЕКТИВНОСТЬ ПРИМЕНЕНИЯ БИОЛОГИЧЕСКИ АКТИВНЫХ ПРЕПАРАТОВ НА ПОСЕВАХ СОИ В УСЛОВИЯХ НЕЧЕРНОЗЕМНОЙ ЗОНЫ РОССИЙСКОЙ ФЕДЕРАЦИИ

Ecologically sustainable and economically feasible crop cultivation technologies, including application of biologically active substances, are required for formation of a consistently high and excellent soybean yield. These substances, when used in minimal doses for pre-sowing treatment of seeds and vegetative plants, provide high field germination and plant resistance to unfavorable environmental factors, promote an increase in productivity by ensuring accelerated germination of seeds, their increased germination capacity and resistance to unfavorable agro-climatic conditions of the growing season. The aim of the research was to determine the degree of influence of various combinations of biological products and treatment methods on growth processes and productivity of soybean of the northern ecotype. The influence of various types of pre-sowing seed treatment on germination energy, germination capacity and morphometric parameters of soybean shoots was studied. The biological product “Floravit” was used in the experiments in combination with rhizotorphin, seeds were treated before sowing; the germination energy, laboratory and field germination capacity were found. Also, additional treatment of vegetating plants was carried out with the biological product “Floravit”. Observations of the symbiotic activity of plants were carried out, the productivity of plants was recorded at the end of the growing season. It was found that soaking of soybean seeds in water solution of “Floravit” (concentration - 1.4 · 10-4 g / ml; consumption - 1 l / kg) with subsequent treatment with rhizorphin (consumption - 3–5 g / kg) has a growth-stimulating effect at the initial stages of plant development, promotes fast and friendly shoots. Afterwards, the plants form a more powerful symbiotic apparatus and higher productivity. The obtained results - an increase in germination energy, laboratory and field germination capacity, symbiotic activity of plants and parametres of crop yield structure indicate a fairly high efficiency of “Floravit” application.

Insights into the early stages of plant-endophytic bacteria interaction.

The plant holobiont is a complex entity composed of the plant and the organisms that live in and on it including its microbiota. The plant microbiota includes, among other microorganisms, bacterial endophytes, which are bacteria that can invade living plant tissues without causing symptoms of disease. The interaction between the endophytic bacterial microbiota and their plant host has profound influences on their fitness and depends on biotic and abiotic factors. For these interactions to be established, the bacteria have to be present at the right time, in the right place either colonizing the soil or the seed. In this review we summarize the current knowledge regarding the sources of the bacterial endophytic microbiome and the processes involved in the assemblage of the resulting community during the initial stages of plant development. The adaptations that allow the spatial approximation of soil- and seed-borne bacteria towards infection and colonization of the internal tissues of plants will be addressed in this review.

Response of sunflower (Helianthus annuus L.) at early growth stage to cadmium exposure

The study carried out in greenhouse conditions at daylight in order to evaluate the effects of increasing Cd exposure on growth and physiological characteristics of sunflower at early growth stage as well the accumulation of some metal nutrient ions. Accordingly, the soil treated with six levels of Cd (0, 50, 100, 250, 500, and 1000 µM CdCl2.H2O). The plant growth and root elongation unfavorably affected by Cd exposure and detrimental effect of Cd on plant growth was appeared shoot more than roots. Growth tolerance index (GTI), relative water content (RWC), the contents of chlorophyll (Chl a+b) and carotenoids (Car), the uptakes of zinc (Zn), potassium (K), and calcium (Ca) in shoot and root, and total accumulation rate (TAR) of Zn were decreased by Cd exposure as well as bioaccumulation and translocation of Cd. Furthermore, increasing Cd doses augmented the concentrations and uptakes of Cd in shoot and root, net accumulation of Cd via roots, the TAR of Cd, membrane permeability (MP) and the rate of Car/Chl caused by its toxic effects. This study demonstrated that Cd exposure cause a reduction in growth due to affecting morphological and physiological characteristics of sunflower in the initial stages of plant development.

ИЗМЕНЧИВОСТЬ И НАСЛЕДУЕМОСТЬ РЯДА ПРИЗНАКОВ У ПРОСТЫХ ГИБРИДОВ F1 КУКУРУЗЫ ПРИ ПОНИЖЕННОЙ ТЕМПЕРАТУРЕ И В ОБЫЧНЫХ УСЛОВИЯХ

The values of heritability coefficients of parental genotypes were determined for such characters as "frequency of callus formation", "frequency of somatic embryogenesis","frequency of plant regeneration" under normal and stressful in vitro conditions in simple maize F1 hybrids. The highest value of the coefficient of heritability of maternal genotypes in traits studied in vitro was found for “frequency of somatic embryogenesis” at low temperatures. The variability and heritability of characters during the initial stages of plant development under the actionof low temperatures, as well as quantitative characteristics of the plant and male gametophyte, were evaluated. Hybrids in which the inbred lines A239 and 092 were used as maternal genotypes showed under stress higher indices of the studied traits both invitro conditions and at the seed level. For the characters “number of grains per row” and “plant height”, the highest heritability coefficients of the interaction of maternal and paternal genotypes were noted. Hybrids A239xP502 and Co125xMK159 were selected by the higher values of the studied quantitative traits. Hybrid combinations with significantly high meanings of the most of the studied characters can be used to create cold-resistant and productive corn hybrids

ВЛИЯНИЕ БИОПРЕПАРАТОВ НА НАЧАЛЬНЫЕ РОСТОВЫЕ ПРОЦЕССЫ СЕМЯН СОИ

The creation of effective biologized pre-sowing methods of seed treatment of cultivated plants against the background of the conditions of modern absolute "chemical" farming has theoretical and practical significance in the construction of agrobiocoenosis on a biological platform. This work reflects the results of the laboratory studies to identify the effect of pre-sowing treatment on the morpho-physiological characteristics of seedlings at the initial stage of plant growth of promising soybean varieties of the northern ecotype (Zusha, Osmon, Lantsetnaya, Mezenka). The study of the growth processes in the laboratory at the initial stages of plant development makes it possible to neutralize the influence of barriers to the ecological heterogeneity of the environment. It was found that pre-sowing treatment of soybean seeds with an amino acid biostimulant intensifies not only their germination, but also the development of seedlings even against the background of the use of chemical fungicides: the process of water absorption by the seeds is catalyzed, the lag period is shortened, the ratio of biomass to seedling length increases by 78%, as a result, a more powerful root system is formed. Soybean seed inoculation leads to an increase in germination energy. The most pronounced stimulating effect was observed with the method of applying microbiological preparation in the form of spraying: the mass of seedlings was higher than the values of the control variants by an average of 24.0% in varieties Mezenka, Lantsetnaya and Zusha, and the length of seedlings was higher by 23.6% for all varieties. The stimulating effect of the tested drugs arises due to a positive effect on the physiological and biochemical processes of seedlings at the early stages of ontogenesis, which contributes to the realization of the high potential productivity of modern soybean varieties in the future.

Cell-wall degrading enzymes for the control of Meloidogyne javanica

The potential of cell-wall degrading enzymes (chitinase, β-1,3 glucanase, endo-cellulase and exocellulase) in the control of M. javanica in vitro and in vivo was investigated in this study. The enzymes were produced by solid-state fermentation using Beauveria bassiana, Trichoderma harzianum and Metarhizium anisopliae, microorganisms that are used in the biological control of agricultural pests. The bioproducts were efficient in the treatments in vitro, presenting high indexes of egg hatching inhibition (66.7-87.0%) and mortality of juveniles (40.0-90.0%). The bioproduct containing enzymes from B. bassiana presented the most promising results. In vivo treatments with all bioproducts on lettuce and tomato cultures during initial stages of plant development demonstrated excellent nematicidal effects in relation to the water-treated control. On lettuce, final egg counts and juveniles in the control treatment were 141 and 452% higher than in treatments containing bioproducts, respectively. The index of penetration of M. javanica on tomato roots was 348% higher in the control treatment than in the treatments using bioproducts. The bioproducts evaluated in this study were efficient in the control of nematodes both in treatments in vitro and in vivo. The results obtained open a new perspective for the use of bioproducts containing cell-wall degrading enzymes for the control of nematodes in agriculture.

Comparison of chemical routes based on inherent safety, health and environmental impacts of accidental and daily operational releases

One of the key decisions made during initial stages of chemical plant design and development is the chemical route selection. A chemical route is considered as the raw material(s) and the sequence of reaction steps that convert them to the desired chemical product. The selection of a chemical route focused on environmental, health and safety (EHS) issues has been given increased attention recently as avoiding hazards related to EHS can be largely achieved during initial stages of plant development. In order to select a route, alternate potential chemical routes need to be assessed and compared. In this work a fuzzy based inherent environmental, health and safety hazard index called EHS-Fuzzy Index is presented to compare chemical routes based on integrated EHS hazards due to accidental releases as well as releases from daily operational activities of the plant. Thirteen parameters representing EHS related hazards are included in the EHS-Fuzzy Index. The lower the EHS-Fuzzy Index the more environmentally friendly, occupationally healthy and safer the chemical route. The EHS-Fuzzy Index was applied in a case of six routes to manufacture methyl methacrylate (MMA). The least hazard was shown in tertiary butyl alcohol (TBA) route.

Alternative Splicing as a Regulator of Early Plant Development.

Most plant genes are interrupted by introns and the corresponding transcripts need to undergo pre-mRNA splicing to remove these intervening sequences. Alternative splicing (AS) is an important posttranscriptional process that creates multiple mRNA variants from a single pre-mRNA molecule, thereby enhancing the coding and regulatory potential of genomes. In plants, this mechanism has been implicated in the response to environmental cues, including abiotic and biotic stresses, in the regulation of key developmental processes such as flowering, and in circadian timekeeping. The early plant development steps – from embryo formation and seed germination to skoto- and photomorphogenesis – are critical to both execute the correct body plan and initiate a new reproductive cycle. We review here the available evidence for the involvement of AS and various splicing factors in the initial stages of plant development, while highlighting recent findings as well as potential future challenges.

Biological nitrogen fixation and plant growth promotion of lodgepole pine by an endophytic diazotroph Paenibacillus polymyxa and its GFP-tagged derivative

Paenibacillus polymyxa P2b-2R is an endophytic diazotroph originally isolated from lodgepole pine. It is reported to fix significant amounts of nitrogen (N) and promote plant growth. To evaluate the endophytic colonization sites, a green fluorescent protein (GFP) derivative of P2b-2R was generated (P2b–2Rgfp), but the effects of GFP modification on the functioning of P2b-2R have not been fully elucidated yet. In this study, we wanted to confirm and contrast the N-fixing and plant-growth-promoting abilities of P2b-2Rgfp with those of the wild-type P2b-2R in lodgepole pine. Pine seedlings were grown in an N-limited environment and harvested 2, 4, 8, and 12 months after inoculation to evaluate the endophytic and rhizospheric colonization by both strains, the amount of N-fixed, and seedling growth enhancement. Both P2b-2R and P2b-2Rgfp strains formed persistent rhizospheric and endophytic populations; fixed N; and enhanced seedling growth continuously after 4 months. P2b-2Rgfp-treated seedlings outperformed the P2b-2R-treated seedlings in terms of biomass only during the initial stages of plant development, but the differences decreased during the trial and were not significant towards the end. To the best of our knowledge, this is the first study that reports the effects of GFP-tagging of an endophyte when inoculated into a gymnosperm tree species.

Влияние гербицидов на численность микроорганизмов и биологическую активность почвы в агроценозах сои

THE INFLUENCE OF HERBICIDES ON THE NUMBER OF MICROORGANISMS AND THE BIOLOGICAL ACTIVITY OF THE SOIL IN THE SOYBEAN AGROCENOSIS I. S. Brovko , V. U. Jashchuk , Y. V. Chabaniuk The use of pesticides and agrochemicals in agriculture affects not only the productivity of crops and the quality of their crops, but also the ecological state of the soil, and as a consequence the quantity and diversity of vegetation cover and soil biota, which is an indicator of the safety of the use of substances in agriculture. Each species of organisms in the biogeocenosis (even insignificant) has multiple connections with a significant number of other species. The disappearance of any species of animals or plants can cause unpredictable consequences and even the destruction of the entire biogeocenosis. Biodiversity can be attributed to objective factors of assessing the state of the environment and the stability of ecosystems. Biological diversity is the basis of the structural and functional organization of living matter of the biosphere, determines the stability and sustainability of ecosystems. It fulfills a regulating function in the implementation of all biogeochemical, climatic and other processes on Earth. Pesticides can influence plant-microbial interactions through their effect on the pathogen or on other soil biota. For soil microorganisms, a certain selective sensitivity to herbicides and pesticides in general is characteristic. Chemical treatments mainly lead to the death of sensitive species and genera of microorganisms, the activation of resistant mutants, and the herbicide used as an energy material. As a consequence, there is a disturbance in the state of equilibrium of the soil ecosystem and, accordingly, the soil self-purification conditions resulting from the activity of successive successive microbial races, the narrowing of the spectrum of microbiological activity due to both the direct microbicidal action of herbicides and through changes in the ecological environment. Purpose of the study. Establish the dependence of changes in the numbers of microorganisms of different ecological-trophic groups on the use of herbicides, the phase of development of soybean plants and the sampling period for the natural ecosystem. In view of the fact that biological diversity, being the basis of living matter of the biosphere, determines the sustainability of ecosystems on the Earth, it is relevant to monitor and evaluate all factors that can influence the state of the agrosphere, identify risk factors, and identify links between them. In the work, generally accepted methods of conducting field experiments, methods of soil microbiology, methods of biochemistry were used. In the field experiments, the effect of herbicides imazamox and clomazone on the number of microorganisms of the main ecology-trophic and taxonomic groups in the soy rhizosphere was studied. The regular effect of preparations in the V2 phase of soybean plants as compared to the soil of the natural ecosystem has been established. It has been suggested that bacteria belonging to the clomazone preparation can use the mineral nitrogen of the soil. The number of mycelial microorganisms (streptomycetes and micromycetes) increased in the phases V 2 and R 2 for soybean plants by 30-40% and 10-15%, respectively. More sensitive to the effects of herbicides were indicators of biological activity of the soil. Thus, the influence of herbicides imazamox and clomazone was significant at the initial stages of plant development, since the R 2 phase, the effect on the indices of the number of microorganisms, the biological activity of the soil and the activity of the symbiotic system was significantly reduced and leveled at the end of the vegetation. A representative index is the phytotoxicity of the soil when using the drugs under study. Thus, the influence of herbicides imazamox and clomazone was significant at the initial stages of plant development, since the R 2 phase, the effect on the indices of the number of microorganisms, the biological activity of the soil and the activity of the symbiotic system was significantly reduced and leveled at the end of the vegetation. A representative index is the phytotoxicity of the soil when using the drugs under study. So, for ecological rationing and ecological expertise of growing technologies, it is necessary to search for and develop more sensitive methods for assessing the impact of pesticides on soil biota. Keywords: soil microbiota, soil biological activity, herbicides, imazamox, clomazone

Вплив лазерного опромінення насіння на ростові процеси та вміст пігментів у проростках олійних культур

Introduction. According to the research of many authors Laser preplant seed treatment may promote germination, accelerate the germination of seeds, the initial stages of growth and development of plants and further increase the resistance of plants to diseases that positively affect their performance. However, the use of laser systems is limited by their size, significant power consumption for low power beams of radiation. Therefore, we studied the effect of laser irradiation on seed growth processes of plants in the early stages of growth and pigment content in seedlings of oil crops using energy-efficient laser systems red and blue light. Methods . Purpose was to investigate the influence of laser irradiation on the growth processes and content of pigments in seedlings of some oilseeds. For the purpose solved such problems - to study the effect of laser irradiation on germination and sprouting seeds to analyze the initial stages of plant development and determine the content of chlorophyll a and b spectrophotometric method. The objects serve the following plants: sunflower normal ( Helianthus annuus L.), winter rape ( Brassica napus L.) , white mustard (Sinapis alba (L.) Rabenh. ). The study took place 2015-2016 years. Irradiation of seeds was carried out by red LED laser (635 nm) and blue (405 nm) light with a capacity of 100 MW. Results and discussion . Studies indicate positive effects of laser irradiation on the initial stages of plant development. Proven positive effect of red light on growth indicators studied aerial parts of plants. Also of note is the positive impact of blue laser on root growth of plants studied species. Proved ineffective triple exposure test plants. All we studied oleaginous set a positive effect of exposure on the content of chlorophyll a and chlorophyll b.

Chemical forms in soil and availability of manganese and zinc to soybean in soil under different tillage systems

Chemical forms of Mn and Zn in the soil and its availability to soybeans grown in a Latosol for 12 years under different tillage systems were studied. The effects of these systems on Mn complexation by soil humic acid (HA) were also evaluated. The field experiment was carried out in a randomized block (three blocks) split-plot experimental design. The main treatments consisted of four tillage systems and the secondary, of three soil sampling depths (0.00–0.05m, 0.05–0.10m and 0.10–0.20m). The tillage systems were no tillage (NT), conventional tillage (CT), minimum tillage (MT) and NT with scarification, every three years. The results presented refers to the last 2 years of the experiment, 2000 and 2001. In average numbers, the Zn content of the 0.00–0.05m layer was lower in soil under CT (2mgkg−1), compared to the other tillage systems (NT and NT with scarification=2.7 and MT=2.8mgkg−1). In general, Zn percentages in exchangeable, organic, oxides and residual forms were not modified by the tillage systems. In turn, the Mn content of the soil surface layer under the NT was higher than in the soil under CT. Mn contents extracted with DTPA were 11 and 5.2mgkg−1 in the soil under NT and CT, respectively. The Mn contents extracted with Mehlich I, Mehlich III and HCl in the soil under CT were 20.8, 8.7 and 16.8mgkg−1, respectively. In the soil under NT, the contents extracted with the same extractors were 27.9, 15 and 29.2mgkg−1. In the surface layer, higher Mn percentages in the organic fraction were found in the soil under NT (19.2%) and NT with scarification (15.9%) than in soil under CT (11.8%). The Mn content of this layer was also positively correlated with the soil organic matter, but none of the extractors used (DTPA-TEA pH 7.3, HCl 0.1molL−1, Mehlich I and III) properly assessed the levels of Mn and Zn available to plants, suggesting the need for further studies. It was not observed presence of Mn in the HA samples by electron paramagnetic resonance (EPR). Since the digestion by nitro-perchloric acid of the HA samples showed the presence of Mn in these samples, it strengthens the hypothesis that Mn was bound to the HA in the form of stable complexes (covalent bonds), since this form of Mn cannot be detected by EPR. During soybean cultivation, Mn concentrations in the leaves did not vary with the tillage methods and were near or below the range considered adequate for the crop. Furthermore, visual symptoms of Mn deficiency in the leaves were observed in the initial stages of plant development, regardless of treatment. This suggests the need for new correlation and calibration studies for micronutrients in Brazil, especially for soils cultivated under the NT.

Comparative study of drought and salt stress effects on germination and seedling growth of pea

Seed germination is first critical and the most sensitive stage in the life cycle of plants compromise the seedlings establishment. Salt and drought tolerance testing in initial stages of plant development is of vital importance, because the seed with more rapid germination under salt or water deficit conditions may be expected to achieve a rapid seedling establishment, resulting in higher yields. The aim of this study was to determine whether the pea seed germination and seedling growth were inhibited by the salt toxicity and osmotic effect during the seedling development, and also identification of the sensitive seedling growth parameters in response to those stresses. Based on the obtained results, pea has been presented to be more tolerant to salt than water stress during germination and early embryo growth. Investigated cultivars showed greater susceptibility to both abiotic stresses when it comes growth parameters compared to seed germination.