Different Phases Of Vegetation Research Articles

Basic and additional ecological niches of soil phytopatogenes on spring wheat varieties in West Siberia

The elucidation of hydrothermal and temporal parameters of the realization of the main and additional ecological niches of jointly parasitizing widespread soil phytopathogenic micromycetes has theoretical and applied significance. The aim of the study was to identify the parameters of the implementation of the main and additional ecological niches by the dominant species of soil micromycetes on spring wheat (Bipolaris sorokiniana Sacc. Shoem., Fusarium poae (Peck.) Wollenw., F. oxysporum Schltdl.) in the system of underground and generative organs of spring wheat varieties. The objectives of the study included determining the level of realization of the main ecological niches by three dominant species of soil pathogenic micromycetes in the system of underground organs of spring wheat varieties in different phases of vegetation, as well as identifying the degree of realization by micromycetes of additional ecological niches in generative organs of spring wheat varieties and assessing the strength of the influence of varieties and conditions of the year on the size of ecological niches in underground and generative organs of plants. The study was conducted on 20 varieties of spring wheat in 2020–2022, in the northern forest-steppe of the Ob region according to generally accepted and author’s methods. It is shown that the soil micromycetes B. sorokiniana, Fusarium poae and F. oxysporum, parasitizing together on the underground and generative organs of spring wheat, have different hydrothermal and temporal parameters of the realization of the main and additional ecological niches. B. sorokiniana is a relatively thermophilic species, its parasitic activity is most successful in underground, especially straw organs, is realized in conditions of unstable humidification, F. poae is a moisture-loving micromycete that prefers underground, especially young organs of spring wheat plants, F. oxysporum is a drought-resistant species that tends to more mature plant organs. As for the generative organs of wheat, B. sorokiniana colonizes them by airborne droplets in humid conditions, keeping them confined to straw-like tissues, the correlation coefficient of B. sorokiniana infection of the ear rods and the SCC of August was equal to r = 0.812 ± 0.412. F. poae could reach ears by vessels, the degree of their colonization by this micromycete was small and practically did not depend on the weather conditions of the year and its representation in underground plant organs. F. oxysporum colonized ears of spring wheat by vessels, and the degree of its representation in pathocomplexes of generative organs closely correlated with its share in pathocomplexes of primary and secondary roots: r = 0.923 ± 0.146.

ЕКСПРЕС-ДІАГНОСТИКА ХЛОРОФІЛУ НА ПОСІВАХ ПШЕНИЦІ ОЗИМОЇ

The purpose of this research is a comparative analysis of the chlorophyll content in two varieties of winter wheat in different periods of plant development using an autonomous field device (N-tester) for operational measurement of nitrogen content and calculation of the optimal dose of nutrient application on winter wheat crops during different phases of vegetation. Methods and materials. The research was conducted in the Oleksandrivskyi and Bobrynetskyi districts of Kirovohrad region on the fields of two farms on winter wheat crops (varieties «Memory» and «Avenue») with selected control plots with an area of 3 m2 each. At the key moments of plant development, before applying fertilizers, chlorophyll was measured using the N-tester «CSM-200 Plus GPS» and the sugar content was measured with a refractometer «HT116ATC», after which the required dose of application of drugs was calculated. In both farms, fertilizing was carried out at the optimal time of fertilizer application, but the rates of fertilizer were radically different. Results. Wheat of the «Memory» variety in the control plot (the total amount of applied nitrogen was 198 kg/ha), starting from the earing phase, looked greener, taller, the ear had a larger size, the indicators of the N-tester and the content of sugars in the control plot had higher indicators, but also the ripening period in the control plot lasted longer than in the rest of the field (the total amount of applied nitrogen per year was 101 kg/ha). Winter wheat of the «Avenue» variety in terms of the main indicators in the control plot (the total amount of applied nitrogen 145 kg/ha) and in the field (the total amount of applied nitrogen 183 kg/ha) almost did not differ: the length of the ear, the height of the plant, and the color are the same, the indicators of the N-tester and the content of sugars are also almost the same. Therefore, it can be concluded that the introduction of an additional amount of 38 kg/ha per year was ineffective and did not increase productivity. Conclusions. Operational measurement of the nitrogen content in field conditions using the N-tester made it possible to effectively calculate the doses of nutrients applied to winter wheat crops during different phases of vegetation and contributed to increasing the yield level of the investigated crop varieties. Keywords: fertilizers, plant nutrition, winter wheat, refractometer, harvest, phases of plant development, chlorophyll, N-tester.

Phenology and Application of Maclura Aurantiaca Nutt Species in Absheron Conditions

Phenological observations at different phases of vegetation on the species Maclura aurantiaca Nutt. introduced in Absheron and cultivated in cultural conditions (beginning of new shoots, budding phase (beginning, end), flowering phase (beginning, mass, end), fruit and maturation), the directions of use of the species were studied. The species Maclura aurantiaca Nutt., belonging to the genus Maclura, which has a multifaceted economic significance, decorative features and resistance to environmental factors, is widely used in the protection of greenery (laying fences and protective forest strips) in the dry subtropical climate of Absheron. The fruits of mackerel are rich in alkaloids, glucosides, morin, rutin, flavonoids containing quercetin, sugar, pectin, protein, fat, resinous substances, organic acids, vitamin C. Vitamin C was also found in the leaves. In folk medicine, an ointment is prepared from the fruits of the orange macula for therapeutic purposes and is used in the treatment of some diseases (gout, salt diseases, rheumatic pains, ankylosis). The infusion of the fruit as a tea is used in hypertension, and the juice is used in various skin diseases.

THE INFLUENCE OF CLIMATIC CONDITIONS ON ACCUMULATION OF BIOLOGICALLY ACTIVE COM-POUNDS IN KOENIGIA WEYRICHII

Koenigia Weyrichii (F. Schmidt) T.M. Schust. et Reveal is a herbaceous perennial plant introduced to the Murmansk and Tomsk regions in the mid–twentieth century. This plant accumulates a sufficiently large amount of flavonoids, which makes it a promising source of biologically active compounds. The purpose of this study was to determine how different location and climatic conditions affect the content of total phenols, flavonoids, antioxidant and antiradical activity of K. Weyrichii ethanol extracts obtained from different plant organs in different phases of vegetation. Inflorescences, leaves of the upper and middle tiers of K. Weyrichii were collected in three places – in the districts of Apatity, Kirovsk (Kola Peninsula, Murmansk region) and Tomsk (Western Siberia, Tomsk region) during flowering and fruiting periods. For ethanol extracts, the total content of polyphenolic components in reaction with Folin-Chokalteu reagent, flavonoids in reaction with aluminum chloride, total antioxidant and antiradical activity determined by phosphomolybdate and DPPH methods, respectively, were determined. The results of ANOVA factor analysis showed that these parameters depend on the place of growth, the period of collection and the type of plant tissue. The higher average value of the accumulation of total polyphenols was observed in Kirovsk – 106.2 мг GAE/г (GAE is the equivalent of gallic acid), the lowest – in Tomsk: 86.1 мг GAE/г. The average value of flavonoid accumulation was higher in Apatity – 4.39 мг,RE/г (RE – equivalent of rutin), less in Tomsk – 3.12 мг RE/г. Lower temperatures, less precipitation, and longer daylight hours in Apatity and Kirovsk contributed to a greater accumulation of flavonoids compared to Tomsk. In the inflorescences during the mass flowering period, there was a greater accumulation of flavonoids and a greater antioxidant activity of extracts at all three sites. The obtained data can be used as a theoretical basis for the rational use of K. Weyrichii as a promising source of flavonoids.

A characteristic of the species composition of pathogenic fungi of the genus Fusarium in corn biocenoses of the Voronezh region.

Corn is one of the main crops of modern world agriculture. It ranks f irst in terms of gross grain harvests and second in terms of acreage, ceding only to the main grain crop of the globe, wheat. The problem of increasing the production of grain and green mass of corn remains one of the urgent tasks of agricultural production. High potential yields very often remain untapped due to diseases, direct losses from which are estimated at 20–50 %. The purpose of this work was to study the species composition of micromycetes on corn collected in different phases of vegetation in May-July 2020 in the Voronezh region, to identify phytopathogenic genus Fusarium fungi, to study pathogenic and phytotoxic strains of the fungi to replenish the collection of the All-Russian Scientific Research Institute of a Phytopathology. Preservation of infectious material of fungi from the genus Fusarium is of no small importance for phytopathological, immunological, breeding, genetic and toxicological studies. As a result of the mycological studies carried out, a lot of fungi isolates from the genera Fusarium, Aspergillus, Cladosporium, Curvularia, Penicillium, Rhizopus, Periconia, Pythium, Trichothecium, etc., isolated from the affected roots, stems and ears of corn in the Voronezh region in 2020 were identif ied. Fungi isolates from seven taxonomic groups: Fusarium fujikuroi Nirenberg (F. moniliforme, F. verticillioides), Fusarium oxysporum Schltdl., Fusarium culmorum (Wm.G. Sm.) Sacc., Fusarium graminearum Schwabe, Fusarium heterosporum Nees & T. Nees (F. lolii ), Fusarium roseum Link (F. sambucinum), Fusarium sporotrichioides Sherb. were tested for pathogenicity and phytotoxicity on seedlings of plant-testers. It has been shown that pathogenic and phytotoxic activity in fungi varies signif icantly between Fusarium species and within the same species. The greatest danger to corn is represented by the species F. sporotrichioides, F. graminearum, F. culmorum, F. fujikuroi, F. oxysporum, F. heterosporum, which have a high intensity of phytotoxic activity associated with the fact that they contribute to the synthesis and accumulation of dangerous toxins in plant tissues. As a result of the conducted studies, 55 strains of fungi from the genus Fusarium belonging to seven species were selected. The isolates, stable in morphological and cultural characteristics and studied for pathogenicity and toxicity, were placed for long-term storage in the Russian State Collection of Plant Pathogenic Microorganisms and Cultivars for Identif ication of Phytopathogenic Microbial Strains at the All-Russian Scientif ic Research Institute of a Phytopathology.

Information system of analysis of geodata for tracking changes of vegetation

The rapid growth of geo-information technology capabilities in the field of spatial data processing and analysis has led to a significant growth of the role of geo-information systems in different areas of human activity. Application of approaches to spatial information processing from satellites new for more effective and efficient assessment of the state of plant cover is caused by growing tendency of availability to data of Earth remote sensing. The article offers an information system that allows to quickly and conveniently track changes in the vegetation. The analysis was carried out on the example of the Chornobyl Area between 2000 and 2020. The Chornobyl Disaster coincides with the period of intensive vegetative plant development. During that period, they are most sensitive to radiation. It has been established that for defining the quantitative state of biomass the NDVI index at different time intervals is most often used. But this index becomes ineffective during periods of weakening of active phase of vegetation. This is therefore of practical interest to assess the possibility of using the K-means clustering for the analysis of space images of vegetation cover at different phases of vegetation. As a result of the research, water surface, land with and without vegetation has been correctly interpreted, thus determining the land with a sparse vegetation and dense vegetation cover. The maps of the vegetation cover according to the normalized vegetative index using the K-medium method were constructed, the method by which changes in vegetation over 20 years can be clearly observed. The accuracy results were verified with the Common Method Bias. According to the calculations, despite all natural cataclysms (temperature increase, drought, winter anomalies of precipitations and temperatures, storms, forest fires), as well as human activity (sanitary clear cuttings, illegal logging), vegetation in the Chornobyl zone continues to grow and its areas will increase, although not so quickly.

Weed Control and Winter Wheat Crop Yield With the Application of Herbicides, Nitrogen Fertilizers, and Their Mixtures With Humic Growth Regulators

Abstract The aim of the present study was to determine the efficacy of the application of mixtures containing various combinations of humic substances, with herbicides and nitrogen fertilizers, in weed control and optimizing the plant nutrition system. We also aimed to evaluate the influence of these substances on winter wheat productivity. Five Ukrainian winter wheat cultivars (‘Kryzhynka,’ ‘Smuhlyanka,’ ‘Slavna,’ ‘Kubus,’ and ‘Mulan’) were sown in a randomized complete block design, with three replications, in the years 2014–2019. The analysis of the effect of the compositions containing herbicides, with various physiologically active substances, in a mixture with humic preparations (Humifield, 4R Foliar concentrate) was performed by counting weeds per square meter in each experimental plot. The best performance in weed control, including perennial species, was obtained from using a mixture of Grodil Maxi herbicide with the humic preparation, Humifield. The crop treatment of this mixture resulted in a 23.6% reduction in weeds, compared to the treatment with the Grodil Maxi herbicide only. At the same time, the complex application of a number of herbicides in a mixture with the humic preparation, 4R Foliar concentrate led to the opposite effect. Various applications of mixtures of humates (4R Foliar concentrate, 5R SoilBoost) with nitrogen fertilizers (ammonium nitrate; carbamide-ammonium mixture) to optimize the winter wheat nutritional system and yield increases have been studied. The highest yield increase of 20%–22% was harvested in the plots treated with 5R SoilBoost and 4R Foliar concentrate plus ammonium nitrate. In addition, the efficacy of wheat crop foliar feeding with mixtures of humates, plus a carbamide-ammonia mixture, in different phases of vegetation has been established. A yield increase of 10.0%–21.4% resulting from the use of such compositions was obtained.

Изучение динамики численности эколого-трофических групп микроорганизмов эпифитной микробиоты Stellaria media и Urtica dioica

The dynamics of the strength of the epiphytic microbiota of the root zone and phyllosphere of the Stellaria media and Urtica dioica in the vegetation phase of plants (seedlings, flowering, fruiting) was studied. The data on the strength of microorganisms of ecotrophic groups are presented: ammonifying bacteria using mineral forms of nitrogen, bacteria of the Escherichia coli group, micromycetes and bacteria in the spore stage. It was determined that the medium-sized microbiota of the Stellaria media is more strengthen than the Urtica dioica, which is probably due to the morphoanatomical features of plants and the metabolites produced. The microbiota of the rhizosphere of plants of the Stellaria media and Urtica dioica is much more strength than the phyllosphere due to the root exudates of plants that provide food for microorganisms. The dynamics of the microbiota of the rhizosphere reflects the unequal level of metabolite production by plants in different phases of vegetation. The total strength of aerobic bacteria that metabolize organic nitrogen in the basal zone of Stellaria media increases in the flowering phase, and in the basal zone of Urtica dioica – in the phase of seedlings.The greatest strength of microscopic fungi during the flowering phase of Stellaria media is probably associated with the production of metabolites by plants and favorable weather conditions for the development of micromycetes. Micromycetes belong to the following genera: Trichoderma, Penicillium, Fusarium, Botrytis, Mucor, Aspergillus, Cladosporium. The strength of phyllosphere microorganisms varies according to the stages of plant vegetation. The Stellaria media and the Urtica dioica have a specific microbial complex, both in the aboveground and underground parts, which varies during the growing season and differs in a certain ratio of ecological and trophic groups of microorganisms.

Toxic, Radical Scavenging, and Antifungal Activity of Rhododendron tomentosum H. Essential Oils.

The chemical composition of eight (seven shoot and one inflorescence) essential oils (EOs) of Rh. tomentosum H. plants growing in Eastern Lithuania is reported. The plant material was collected during different phases of vegetation (from April to October). The oils were obtained by hydrodistillation from air-dried aerial parts (leaves and inflorescences). In total, up to 70 compounds were identified by GC−MS and GC (flame-ionization detector, FID); they comprised 91.0 ± 4.7%–96.2 ± 3.1% of the oil content. Sesquiterpene hydrocarbons (54.1 ± 1.5%–76.1 ± 4.5%) were found to be the main fraction. The major compounds were palustrol (24.6 ± 2.6%–33.5 ± 4.4%) and ledol (18.0 ± 2.9%–29.0 ± 5.0%). Ascaridol isomers (7.0 ± 2.4%–14.0 ± 2.4% in three oils), myrcene (7.2 ± 0.3% and 10.1 ± 1.3%), lepalol (3.3 ± 0.3% and 7.9 ± 3.0%), and cyclocolorenone isomers (4.1 ± 2.5%) were determined as the third main constituents. The toxic activity of marsh rosemary inflorescence and shoot oils samples was evaluated using a brine shrimp (Artemia sp.) bioassay. LC50 average values (11.23–20.50 µg/mL) obtained after 24 h of exposure revealed that the oils were notably toxic. The oil obtained from shoots gathered in September during the seed-ripening stage and containing appreciable amounts of palustrol (26.0 ± 2.5%), ledol (21.5 ± 4.0%), and ascaridol (7.0 ± 2.4%) showed the highest toxic activity. Radical scavenging activity of Rh. tomentosum EOs depended on the plant vegetation stage. The highest activities were obtained for EOs isolated from young shoots collected in June (48.19 ± 0.1 and 19.89 ± 0.3 mmol/L TROLOX (6-hydroxy-2,5,7,8-tetra-methylchromane-2-carboxylic acid) equivalent obtained by, respectively, ABTS•+ (2,2′-amino-bis(ethylbenzothiazoline-6-sulfonic acid) diammonium salt) and DPPH•(2,2-diphenyl-1-picrylhydrazyl) assays). Agar disc diffusion assay against pathogenic yeast Candida parapsilosis revealed the potential antifungal activity of EOs. An alternative investigation of antifungal activity employed mediated amperometry at yeast Saccharomyces cerevisiae-modified electrodes. The subjection of yeast cells to vapors of EO resulted in a three to four-fold increase of electrode responses due to the disruption of yeast cell membranes.

Dynamics of accumulating pollutants and essential elements in the process of plant growth and development

The existing problems in the field of using nanomaterials in biological objects are associated with several factors, including: (1) the lack of a clear mechanism of the impact of nanoparticles on living objects; (2) some difficulties with the visualisation and determination of the kinetics of migration of nanoparticles in biological fluids, tissues, organs and in the body as a whole; (3) lack of knowledge of the ecological safety of nanomaterials. The earlier information on the properties of nanomaterials includes data on the physical-chemical, molecular-biological, cytological, physiological, toxicological, and environmental characteristics of nanomaterials. The toxicological characteristics and ecological safety of biologically active preparations based on nanopowders of iron, cobalt, and copper were studied. It was shown that the investigated iron, copper and cobalt nanoparticles accumulate neither in the soil (after seeds pretreatment) nor in plants and vegetables. However, in the process of plant growth and development, the content of certain metals varies significantly. During the growing season, the amount of pollutants and essential metals was determined both in the herbage and seeds of experimental plants in different phases of vegetation. Evaluating the ability of nanoparticles to accumulate in higher plants and predicting their possible remote toxic effects took place with the help of light and analytical electron microscopy.

SEASONAL DYNAMICS OF POLYSACCHARID CONTENT IN RAW MATERIALS REYNOUTRIA JAPОNICA

The dynamics of the accumulation of water-soluble polysaccharides in various organs of Reynoutria japonica Hout (Polygonaceae), harvested in the Ussuriisk region of the Primorye Territory in different phases of vegetation, has been studied. As a result of the studies, four polysaccharide fractions were isolated from the raw materials of R. japonica organs: water-soluble polysaccharides, pectin substances, hemicellulose A and B, which are fixed in all organs of the plant during the observation period.The chemical composition of R. japonica has been studied insufficiently and unilaterally. The secondary metabolites of the phenolic complex have been studied mainly, whereas there is practically no information on the carbohydrate composition, although this group of compounds plays an important role in the plant ecophysiology and shows a pronounced physiological activity. The conducted studies have established that the maximum content of biologically active polysaccharides (water-soluble polysaccharides and pectin substances) in the leaves is noted in the phase of the beginning of vegetation, in the buds of budding and flowering phases, in the roots in the phase of drying. The content of hemicellulose A and B is characterized by stability and changes insignificantly during the season.The obtained results allow to establish scientifically justified terms of raw material preparation for effective practical use.

QUANTITATIVE DETERMINATION OF FLAVONOIDS IN LAVATERA THURINGIACA L., GROWING IN ALTAI KRAI TERRITORY

Aim. To determine the quantitative content of flavonoids in Lavatera thuringiaca L., the grass, growing in Altai Krai. Materials and methods. The object of the study: Lavatera thuringiaca L. grass, stored at different phases of vegetation in Altai Krai territory. Quantitative determination of flavonoids in the investigated raw material was fulfilled, using differential spectrophotometry method. Results. Maximum accumulation of flavonoids in Lavatera thuringiaca L. grass was found to occur in the period of budding (1.14 %) and blossoming (1.02 %). The sum of flavonoids in terms of rutin, extracted with 70 % ethanol from raw material, stored in different regions, is changed insignificantly and makes 1.00-1.23 %. Conclusions. The results of this work testify expediency of studying Lavatera thuringiaca L. as a source of flavonoids.

СПЕКТР РАСТВОРИМЫХ БЕЛКОВ ЛИСТЬЕВ ЯРОВОЙ ПШЕНИЦЫ ПРИ НЕКОРНЕВОЙ ОБРАБОТКЕ ХЕЛАТНЫМ МИКРОУДОБРЕНИЕМ ЖУСС-2

The spectrum of soluble proteins of spring wheat leaves was studied for foliar treatment with chelated copper, molybdenum-containing microfertilizer ZhUSS-2 (0.1% solution). Electrophoretically, polypeptides with a molecular mass of 13.2 - 145 kD were detected. The qualitative composition of soluble proteins in the leaves of spring wheat plants under the influence of foliar treatment during the vegetation did not change, however, their quantitative changes were observed. During a single treatment of spring wheat in the tillering phase, an increase in polypeptides with a molecular mass of 145 and 94 kD was recorded; the content of polypeptides with molecular weights of 13.2 - 66 kD decreased in comparison with the control sample. When the plants were sprayed twice in the tillering and tubing phases, the content of these polypeptides as well as polypeptides with molecular weights of 45 and 41 kD increased. The content of other detected polypeptides also decreased compared to the control variant. During a three-fold treatment of spring wheat plants in the tillering, tubing and blossoming-flowering phases with the ZhUSS-2 preparation, the number of all detected polypeptides increased in comparison with the control sample. Thus, the response of the metabolism of soluble proteins in the cells of spring wheat leaves to the action of foliar top dressing with copper, molybdenum-containing chelate microfertilizer of ZhUSS-2 brand in different phases of vegetation is different and depends on the dose of exposure. Particular attention should be paid to the role of two polypeptides in the treatment of vegetative plants by ZhUSS-2 M.M. 94 kD and, mainly, 145 kD. There is a reason to believe that copper molybdenum-containing chelate microfertilizer ZhUSS-2 exhibits the action of an abiogenic elicitor, which leads to activation of the gene apparatus of cells. The possible functional role of these proteins is discussed.

Application of fuzzy set theory in agro-meteorological models for yield estimation based on statistics

Fuzzy logic model is proposed, allowing to obtain a comprehensive numerical evaluation of the considered agronomic site for suitability of cultivation of the given crop culture. The estimate is based on the analysis and «weighting» of the numerical parameters - the relative deviations of the average values of meteorological parameters (for the area) from their optimal values for given crops in different phases of vegetation. Weight parameters are determined in accordance with their importance in the list of agronomic requirements for cultivation of specified crops. The degree of agronomic suitability of site for cultivation of a given crop is expressed as a number between 0 and 1. It can serve as a fitness assessment and as a tool for ranking farming territories to grow crops. The algorithm can be significantly detailed and is supplemented by inclusion in the consideration of several additional meteorological parameters and soil parameters.

Influence of salinity stress on the height and productivity features of durum wheat samples in different phases of vegetation

Influence of salinity stress on the morphological features of durum wheat in different phases of vegetation is studied in the work. It is revealed that in earlier phases the samples have weak stability, but further salt-stability increases.

Measurement and modelling ozone fluxes over a cut and fertilized grassland

Abstract. During the GRAMINAE Integrated Experiment between 20 May and 15 June 2000, the ozone flux was measured by the eddy covariance method above intensively managed grassland in Braunschweig, northern Germany. Three different phases of vegetation were covered during the measuring campaign: tall grass canopy before cut (29 May 2000), short grass after cut, and re-growing vegetation after fertilization (5 June 2000). Results show that beside weather conditions, the agricultural activities significantly influenced the O3 fluxes. After the cut the daytime average of the deposition velocity (vd) decreased from 0.44 cm s−1 to 0.26 cm s−1 and increased again to 0.32 cm s−1 during the third period. Detailed model calculations were carried out to estimate deposition velocity and ozone flux. The model captures the general diurnal patter of deposition, with vd daytime values of 0.52, 0.24, and 0.35 cm s−1 in the first, second and third period, respectively. Thus the model predicts a stronger response to the cut than the measurements, which is nevertheless smaller than expected on the basis of change in leaf area. The results show that both cut and fertilization have complex impacts on fluxes. Reduction of vegetation by cutting decreased the stomatal flux initially greatly, but the stomatal flux recovered to 80% of its original value within a week. At the same time, the non-stomatal flux appears to have increased directly after the cut, which the model partially explains by an increase in the deposition to the soil. A missing sink after the cut may be the chemical interaction with biogenic volatile organic compounds released after the cut and exposed senescent plant parts, or the increase in soil NO emissions after fertilization. Increased canopy temperatures may also have promoted ozone destruction on leaf surfaces. These results demonstrate the importance of canopy structure and non-stomatal pathways on O3 fluxes.

Content of essential oil and of ledol in leaves of marsh rosemary (Ledum palustre L.) during different phases of vegetation

Content of essential oil and of ledol in leaves of marsh rosemary (Ledum palustre L.) during different phases of vegetation

RESEARCH CONCERNING THE CONTROL OF THE SPECIE Abrosia artemisifolia L.WITH THE HELP OF ERBICIDES

Recent studies confirms the fact that Abrosia artemisifolia L. sin A.elatior., specie has spread from the west of the country to the central; and south areas, invading agricol crops, provoking great production losses if the intervention in not efficient and made in due time. In the present paper there are presented the effect of several tested herbicides in different phases of vegetation, in climatic conditions of 2006-2007.

SOLINIZATION INFLUENCE ON STRUCTURE YIELD ELEMENTS OF DURUM WHEAT VARIETIES (T. DURUM DESF.) IN TERMS OF PLANT DEVELOPMENT STAGE

The studies were carried out at the Dagestan Experimental Station of VIR. The most salt-tolerant varieties of durum wheat of different ecological and geographical origin served as the material for the study. Plants were exposed to salinity in different phases of vegetation. In all phases (germination, tillering, budding, heading), the number of grains from the main ear is most susceptible to salinity (58.0%, 73.5, 75.1, 77.0% of control, respectively). Indicators of other traits: plant height - 68.0%, 83.0, 86.2, 86.6; the number of spikelets in an ear – 72.5, 84.4, 87.3, 93.0; ear length - 74.0, 82.8, 84.0, 88.3%, respectively. In the early stages of development (germination, tillering), durum wheat varieties show poor resistance to salinity. Salt tolerance growing to heading is a manifestation of the body's adaptation to the accumulation of toxic ions under conditions of increasing salinity due to water evaporation and the pulling of salts into the root layer during the growing season.