Nitrogen Reserves Research Articles

A review on bacterial enriched vermicompost and its applications

Generation of the massive quantity of solid waste around the globe is a major ecological and technical problem. Vermicomposting may be the viable option to handle solid waste in an environmentally friendly way. Vermicompost have higher level of available nutrients like carbon, nitrogen, phosphorous and potassium, calcium and magnesium which are derived from the wastes. Many researchers have attempted to evaluate for development of efficiency vermicompost by using varieties of earthworms. The use of earthworms in the degradation of different types of wastes is continuing from the past so many years. These wastes include industrial, agricultural of plant debris and domestic waste papers and cattle dung. Fixed nitrogen is a limiting nutrient in most environments, with the main reserve of nitrogen in the biosphere being molecular nitrogen from the atmosphere. Molecular nitrogen cannot be directly assimilated by plants, but it becomes obtainable through the biological nitrogen fixation process that only prokaryotic cells have developed. Vermicompost is an effective carrier for bacterial growth so that the symbiotic bacterial species such as Mycorrhiza and Dyaztotor of helps in the rapid growth of plant while Azotobactor, Rhizobium involves in the fixation and storing of nitrogen for plants. This review focus on the vermicomposting and microbial enrichment of vermicompost for the exceed crop production.

Beyond floral initiation: the role of flower bud dormancy in flowering time control of annual plants.

The phenology of temperate perennials, including the timing of vegetative growth and flowering, is well known to be controlled by seasonal dormancy cycles. Dormant structures are known as buds and have specialized covering structures, symplastic isolation from the plant, and often autonomous stores of carbon and nitrogen reserves. In contrast, in annual plants, our current understanding of the control of the timing of flowering focuses on the mechanisms affecting floral initiation, the transition from a vegetative apical meristem to a inflorescence meristem producing flower primordia in place of leaves. Recently we revealed that annual crops in Brassicaceae exhibit chilling-responsive growth control in a manner closely resembling bud dormancy breakage in perennial species. Here I discuss evidence that vernalization in autumn is widespread and further discuss its role in inducing flower bud set prior to winter. I also review evidence that flower bud dormancy has a more widespread role in annual plant flowering time control than previously appreciated.

Influence of the dynamics of stocks of mobile forms of nitrogen in gray forest soil and the use of fertilizers on the yield of oats under various weather conditions

In a long-term field experiment on the gray forest soils of the Vladimir opole, the influence of mineral fertilizers and the aftereffect of cattle manure, their interaction on the yield of oats going 2nd crop after the occupied steam, and the dynamics of mobile nitrogen forms under various weather conditions were studied. The determining role of ammonium nitrate nitrogen in the composition of NPK and the aftereffect of cattle manure in increasing the yield of oats has been established. The results of the study indicated that the culture was fed mainly with the nitrate form of nitrogen. A high degree of correlation was revealed between the reserves of N-NO3 in the soil layer of 0–40 cm, formed as a result of the transformation of soil nitrogen and fertilizers to oat seedlings, and its yield (0.981 R2 0.787). The influence of fertilizers and weather conditions on the formation of nitrate nitrogen reserves in the phases of growth and development of oats and their dynamics, ensuring the achievement of high grain yield and quality, are determined. Depending on weather conditions and fertilizer systems, the coefficients of using N-NO3 formed during the growing season of oats for nitrogen removal by grain (40.7–66.6%), grain and straw (58.3–75.0%), grain, straw and crop-root residues (71.2–88.6%) are calculated. In nitrogen-fertilized variants, on average, at 4 levels of manure aftereffect (0, 40, 60 and 80 t/ha), they were highest when using a single dose of N40P40K40, when using a double dose of N80P80K80, they significantly decreased. On average, at 4 levels of mineral fertilizer application (0, P40K40, N40P40K40 and N80P80K80), the utilization coefficients of N-NO3 formed during the growing season with the aftereffect of manure of 60 t/ha were maximum. When N80P80K80 is combined with the aftereffect of organic fertilizers of 80 t/ha, the highest losses of N-NO3 due to denitrification and leaching are possible.

Tracing carbon and nitrogen reserve remobilization during spring leaf flush and growth following defoliation.

Woody plants rely on the remobilization of carbon (C) and nitrogen (N) reserves to support growth and survival when resource demand exceeds supply at seasonally predictable times like spring leaf flush and following unpredictable disturbances like defoliation. However, we have a poor understanding of how reserves are regulated and whether distance between source and sink tissues affects remobilization. This leads to uncertainty about which reserves-and how much-are available to support plant functions like leaf growth. To better understand the source of remobilized reserves and constraints on their allocation, we created aspen saplings with organ-specific labeled reserves by using stable isotopes (13C,15N) and grafting unlabeled or labeled stems to labeled or unlabeled root stocks. We first determined which organs had imported root or stem-derived C and N reserves after spring leaf flush. We then further tested spatial and temporal variation in reserve remobilization and import by comparing 1) upper and lower canopy leaves, 2) early and late leaves, and 3) early flush and re-flush leaves after defoliation. During spring flush, remobilized root C and N reserves were preferentially allocated to sinks closer to the reserve source (i.e., lower vs upper canopy leaves). However, the reduced import of 13C in late versus early leaves indicates reliance on C reserves declined over time. Following defoliation, re-flush leaves imported the same proportion of root N as spring flush leaves, but they imported a lower proportion of root C. This lower import of reserve C suggests that, after defoliation, leaf re-flush rely more heavily on current photosynthate, which may explain the reduced leaf mass recovery of re-flush canopies (31% of initial leaf mass). The reduced reliance on reserves occurred even though roots retained significant starch concentrations (~5% dry wt), suggesting aspen prioritizes the maintenance of root reserves at the expense of fast canopy recovery.

The influence of biological products and growth regulators on the yield and quality indicators of pea seeds of various varieties.

Peas are an important agricultural crop of great importance in human and animal nutrition. Peas, being a legume crop, help replenish nitrogen reserves in the soil. In field studies of the Federal State Budgetary Scientific Institution of the Federal Scientific Center of Legumes and Goat Crops (Oryol region), the influence of various growth regulators and biological products on the yield and quality indicators of pea seeds of the Nord and Multik varieties was studied. Pea plants are grown on dark gray forest, medium loamy soil of average cultivation. Before sowing, pea seeds were treated with solutions of Kornevin, Albit and Epin-extra by soaking for 5 hours. Solutions of the drugs were used at a concentration of 10-6 M, then dried and treated with Rizotorfin before sowing. Growth rates during the growing season and the yield of pea plants were determined. The content of protein, starch and amylose in starch was determined in the seeds. Research results have shown that the yield of pea plants depends on weather conditions. Under favorable weather conditions, the highest yield was obtained from the pea variety Nord (42.2 c/ha) in the variant with seed treatment with Kornevin, and in the Multik variety (43.0 c/ha) when treated with Rizotorfin. In arid conditions, the highest yield of peas of the Nord variety was obtained using the preparations Epin-extra and Kornevin. The highest yield of peas of the Multik variety was obtained using the preparations Rizotorfin, Kornevin and Epin-Extra. The research results, confirmed by statistical evaluation, showed that bioregulators and growth regulators help stimulate the amount of nitrogen supplied to plants, as well as the synthetic processes of protein synthesis. This contributed to improving the quality of seeds and green mass.

BIOLOGICAL NITROGEN FIXATION AS A WAY OF INCREASE YIELD OF SOY

The article highlights the importance of soybeans as one of the main agricultural crops for the life support of society with food. It is well known that soybeans have been the main high-margin crop for many global farmers, including Ukraine, in recent years. The interest in this crop continues to grow as new opportunities for its sale abroad open up, especially in such a giant country as China, the world's largest soybean importer. The right variety accounts for more than 50% of production success. It is important to identify and create optimal conditions for realising the potential nitrogen-fixing activity of soybeans of each variety in specific soil and climatic conditions. Scientists have pointed out that the main reasons that significantly limit symbiotic fixation in our conditions are relatively drier soybean cultivation conditions, especially in the face of abrupt climate change. However, it is also noted that the starting rates of nitrogen fertilisers + symbiotically fixed nitrogen can only offset part of the soybean plants' need for a yield of 4.0 t/ha. The air contains about 76% of nitrogen in the form of N2 gas, which is not available for plant nutrition. However, thanks to the unique ability of legumes to form symbiotic relationships with bacteria of the Bradyrhizobium and Rhizobium genera, N2 gas is converted into an ammonium form of nitrogen suitable for plant use. This interaction takes place in the nodules, which contain the respective bacteria. According to established data, up to 70% of the total nitrogen consumption of soybeans is obtained through biological fixation of nitrogen from the air through symbiosis with nodule bacteria. Based on the analysis of scientific publications on the symbiotic productivity of soybean crops in Ukraine and the world, the indicators of biological fixation by soybean crops in the context of the main soybean producing countries are presented and the importance of soybean cultivation in Ukraine is proved. It is confirmed that soybeans are an important strategic crop in Ukraine, which contributes to the stabilisation of agriculture, increase of soil fertility and nitrogen reserves, eliminates protein deficiency and helps to solve the food problem. The increase in gross soybean harvest is not only due to the expansion of sown areas, but also due to higher yields. To increase the efficiency of soybean production, it is proposed to introduce a set of innovative solutions at different stages of production, as well as to use new, productive varieties. In many publications, the authors emphasise that 30-35% of success in soybean cultivation depends on the right choice of variety and optimally selected technological methods of growing this crop.

Polyamines in Canadian barley grains: Determination of their content and relationship with protein level

Barley is one of the important crops with diverse end-use purposes. In every use of barley grains, the protein fraction plays an important function impacting the quality of final products. Polyamines, having multiple nitrogen atoms in their chemical structure (e.g., putrescine, spermidine, and spermine), may be linked to the levels of protein and nitrogen reserves. In this study, thirteen Canadian barley varieties were characterized for their total polyamines and protein content. The effects of extractants on the extractability of polyamines were considered, and HCl (1 M) was found to be more effective than trichloroacetic acid (5% w/v) in extracting free polyamines from whole barley flour. The total polyamines content of barley grains varied from 6.46 to 11.47 mg/100 g dry basis and spermidine was the most abundant. Polyamine represented 0.045–0.071% w/w grain protein. Significant and positive correlations were found between protein content and levels of total polyamines (r = 0.798), putrescine (r = 0.771), and spermine (r = 0.668). Principal Component Analysis and K-Means Cluster Analysis divided the barley samples into one cluster (hulless barley for food) differentiated from the other (hulled barley for malting and feed) by their superiority in polyamine and protein content.

Evaluation of site-specific management practices to reduce the heterogeneity in grapevine vigor, yield, and grape composition: Doctoral thesis abstract

During eight consecutive seasons (2014-2021) the intra-plot heterogeneity of vigor in a cv. Tannat vineyard in Uruguay was studied. Such variability was assessed during three years (2015, 2016 and 2017) using the Normalized Difference Vegetation Index (NDVI), calculated from aerial images. High-resolution (0.2 m) multispectral images were obtained over the ground to define contrasting vigor zones: high (HV) and low (LV). In winter 2020, trunk diameter was assessed to corroborate the interannual stability of vigor, and positive correlations were established between NDVI and vegetative growth parameters. A complete description of soil physical and chemical parameters was carried out. Climate data (rainfall, temperature, relative humidity and light), vegetative growth (leaf area; leaf nitrogen and potassium; pruning weight), yield (number of bunches per plant, bunch weight, berry weight) and grape composition (total soluble solids, acidity, pH, anthocyanins and total phenols) were used. In addition, site-specific management techniques were employed according to vigor zone to influence yield and grape quality and reduce heterogeneity. For HV, treatments were aimed at reducing water and nitrogen inputs and improving microclimatic conditions in the cluster zone. In LV, on the other hand, treatments were aimed at increasing vegetative growth and yield with water and nitrogen supplementation. Although a 1 ha plot can be considered homogeneous from a topographic, edaphological and climatic point of view, this study demonstrated the existence of great variability in soil variables, production parameters and grape composition. The HV zone was associated with higher levels of leaf area, pruning weight, yield (higher berry and bunch weight) and bunch disease incidence than the LV zone. These HV zone characteristics were the result of a deeper and more structured soil, with higher organic matter content, nitrogen reserves and clay content, and abundance of montmorillonite-type clay. These soil properties in the HV zone proved to be more conducive to root growth, particularly fine roots, with better vertical and horizontal distribution. The LV zone, was distinguished by a shallower and more compact soil which negatively conditioned root growth. New information was provided on the interaction of the soil-plant-atmosphere system. In particular, the dominant role of water availability in the first place and soil nitrogen availability in the second place in establishing plant vigor. The effect of nitrogen on plant response was highly dependent on soil water availability. The gradient of vine vigor and yield between the two zones remained stable over the years, regardless of climatic conditions. This indicates that soil characteristics can mitigate or enhance the effects caused by climatic conditions. The determination (possible by remote sensing) of the vigor zones of a plot is a prerequisite for proposing soil and crop management practices that optimize the use of resources and ensure the economic and environmental sustainability of wine production.

Protein reserves elucidate the growth of microalgae under nitrogen deficiency

Nitrogen (N) starvation is commonly used in the microalgae industry to induce biosynthesis of value-added products, such as astaxanthin and triacylglycerols. Microalgal adaptation to N starvation not only has an effect on biomass yield but also relates to a topic of N storage and utilization. Here, we show that only 30 % of saturated N availability and 47 % of maximum protein content is necessary to maintain a chemostat of microalga Graesiella emersonii growing at 0.96 d−1. The additionally absorbed nitrogen are transformed mainly as proteins to maintain reserves in metabolic capacity, as demonstrated by the proteomic resources allocation analysis. Such intracellular nitrogen reserve can be considered as an advanced nitrogen storage and utilization strategy as it shows a highly efficient utilization of nitrogen resources in cells. The results allow us to identify kinetics of microalgal response to N availability that is basic to future metabolic engineering.

Nitrogen regime of soddy-podzolic soil with long-term use of different types and combinations of mineral fertilizers

The purpose of the work is to study the effect of various types and combinations of mineral fertilizers on the fractional composition of nitrogen in soddy-podzolic soil in a long-term stationary experiment and compare it with a virgin analogue. The studies were carried out in 2016 and 2018 on the experimental field of the Perm Research Institute of Agriculture after harvesting barley in an eight-field crop rotation deployed on soddy-podzolic heavy loamy soil. The experiment scheme: without fertilizers: N90; Р90; К90; N90P90; N90K90; P90K90; N90Р90К90. To assess the effect of nitrogen, phosphorus, potash fertilizers and their combinations on the nitrogen regime of soddy-podzolic soil, the arable soil was compared with the virgin analogue. The nitrogen fund of soddy-podzolic soil of a long-term stationary experiment is represented by 64…71 % non-hydrolyzable and 17…22 % hardly hydrolyzable forms of nitrogen. Long-term use of various types and combinations of mineral fertilizers did not significantly change the ratio of nitrogen fractions characteristic of virgin soils of this type. Nitrogen fertilizers, both with one-sided application and in combination with potassium chloride (N90К90) and superphosphate (N90P90), contributed to an increase in the total nitrogen content in the arable soil layer by 10…20 % relative to the control, mineral nitrogen compounds - by 2…3 times. Unilateral application of potash fertilizer provided an increase in the content of total nitrogen in the soil by 12 %, the introduction of superphosphate did not have a signi cant effect on the nitrogen regime of the soil. Long-term use of complete mineral fertilizer (N90P90K90) only in this way: (N90P90К90) contributed to maintaining total nitrogen at the level of virgin soil - 1490 mg/kg. Long-term unilateral application of nitrogen fertilizers increased the content of nitrate nitrogen in the soil over the entire meter layer by 1.5-2.5 times, ammonium - by 1.5-14.6 times. The reserves of mineral nitrogen in the variants N90P90, N90K90, and N90P90K90 in the 0-20 cm layer increased 2-3 times, in the 0-100 cm layer - 2 times relative to the control variant.

The effect of crop rotations and mineral fertilizers on the fertility of chestnut soil

Relevance. The task of preserving and increasing soil fertility is urgent, since it is closely related to crop yields.Methods. The research was carried out in the arid zone of the Stavropol Territory at the Prikumskaya experimental breeding station in four 6-pole crop rotations from 1969 to 2022.The purpose of the research is to study the effect of saturation of grain crop rotations with pure steam on various nutrition backgrounds on the fertility of chestnut soil in the conditions of the Eastern Caucasus.Results. Over 53 years of research, the content and reserves of humus in the arable soil layer in grain-steam crop rotations decreased by 0.18–0.22% and 4.7–5.8 t/ha at the control, on a fertilized background — 0.04–0.08% and 1.0–2.0 t/ha, and in crop rotation without pure steam, on the contrary, increased, respectively, by 0.05% and 1.3 t/ha and 0.21% and 5.5 t/ha. On a natural background, the mineralization of organic matter took place much more intensively than on the variants with the introduction of fertilizers. Nitrate nitrogen reserves in crop rotations with 50.0% and 33.3% of pure steam decreased by 7.6 kg/ha and 1.3 kg/ha at the control, and on a fertilized background in crop rotation with 50.0% of pure steam — by 3.5 kg/ha. In other variants of the experiment, the amount of nitrogen increased. The maximum content of this element on all food backgrounds was noted in the crop rotation without pure steam. In all variants of the experiment, the content of mobile phosphorus and exchangeable potassium increased at the control by 0.7–2.5 and 31–62 mg/kg, and on a fertilized background by 7.2–20.0 and 12–38 mg/kg of soil. The application of mineral fertilizers contributed to an increase in phosphorus reserves by 13.6–44.6 kg/ha and a decrease in potassium by 20–63 kg/ha compared to the control.

The Influence of Logging Equipment on the Content, Stock and Stratification Coefficient of Elements of the Mineral Nutrition of Plants in the Soils of the Taiga Zone of Karelia

This study was carried out in the territories of Northern Europe, in the middle taiga subzone of Karelia. The paper presents the results of a study of an experiment on logging to study the impact of controlled logging using supervised logging with controlling cutting (SLCC) and conventional logging (CL) on the properties of soils (horizons O, E and BF) in a spruce forest 15 years after logging. Virgin forest (VF) was used as a control. The volume weight of soils, the contents of carbon, nitrogen and potassium in different soil layers (layers O, E and BF), as well as reserves of C, N and K and their stratification coefficients SRs (SR1 [O:E], SR2 [O:BF] and SR3 [E:BF]) were studied. The results showed a tendency to increase the volume weight of soils of anthropogenically disturbed (CL and SLCC) areas can be measured. The obtained data demonstrated that there was no sharp change in the contents or stocks of the studied elements between the anthropogenically disturbed (CL and SLCC) and undisturbed areas (VF). The largest reserves of carbon, nitrogen and potassium were noted in the upper horizons of the soils of all sites, averaging 35.6, 1.27 and 0.073 t/ha, respectively. In the lower horizons of the studied soils, the values were lower. The values of the stratification coefficients in the studied soils were arranged in decreasing order as SR2 > SR1 > SR3. At the same time, the general trend of unidirectional changes in the SR values for carbon and potassium in soils was noted; the data for nitrogen were somewhat different. The results showed a marked decrease in SOC concentration with an increase in soil depth. Higher rates of cellulose decomposition were observed in anthropogenically disturbed areas (CL—69.0 ± 3.6%; SLCC—57.4 ± 3.5%) compared with virgin forest (VF) (53.7 ± 3.1%), which is consistent with the results of other studies in the taiga zone. The data obtained indicate the importance of a more accurate assessment of the contents and stocks of elements, as well as the need to use tests for soil biological activity.

Concentration and reserves of nitrogen in soils and plant matter in blocks of grass ecosystems of the North‐Western Precaspian region, Russia

Aim. Determination of phytocenosis productivity, nitrogen concentration and reserves in blocks of plant associations and by soil types in the North‐Western Precaspian region of Russia. Methods. Comprehensive research on the accumulation of organic matter and nitrogen in five blocks of plant matter, six plant associations and three types of soil by season using well‐known methods of accounting and analysis of soils and plants. Results. The regularities of phytomass formation, changes in nitrogen concentration and reserves in the main soil types and six plant associations for the 2011–2018 seasons were revealed. Conclusions. Ephemeroid‐wormwood‐cereal, ephemeroid‐wormwood, cereal‐wormwood, forb‐campfire and mixed‐grass‐campfire plant communities formed on light chestnut soil are the most productive, with a total productivity of 24.34 t/ha. The maximum nitrogen concentration was observed in the cereal‐wormwood, wormwood‐saltwort, forb‐saltwort and cereal‐saltwort associations – 1.9, 1.97, 2.2, and 2.57%, respectively, which is due to the predominance of Artemisia taurica Willd., Artemisia lercheana Web.ex Stechm. and Salsola iberica Sennen&Pau. In associations where there are representatives of the Poaceae, Brassicaceae and Caryophyllaceae, nitrogen decreases to 1.72–1.74%. Its value was higher on light‐chestnut soil, being 1.82% of absolutely dry mass, while on meadow‐chestnut soil it decreased to 1.75 and on saline soil is typically 1.38%. In the root mass of plant associations, its indicators were 3.2 times less than in the above ground mass. Nitrogen reserves by blocks of plant matter formed the following decreasing series: roots ≥ green mass ≥ rags ≥ felt. In the input part of the balance in plant associations, 171.6 nitrogen accumulates on light‐chestnut soil, 63.1 on meadow‐chestnut soil, 49.1 kg/ha on automorphic typical saline soil, and 171.9; 64.3 and 58.1 kg/ha in the expenditure part, respectively. the balance of nitrogen in the first type of soil is formed with a minimum deficit of 0.6 kg/ha, 1.2 and 9 kg/ha, respectively.

Environmental irradiance and nitrogen source variability trigger the intracellular carbon and nitrogen reallocation of Gracilariopsis lemaneiformis (Rhodophyta)

A rhodophyte Gracilariopsis lemaneiformis is widely cultivated for food, carbon sequestration and bioproducts, and commonly experiences changing irradiance levels and nitrogen sources that might influence the productivity and biochemical composition of the alga. To explore optimal culture conditions or manipulations to gain best yield of carbohydrates and amino acids of G. lemaneiformis during mariculture, we cultured G. lemaneiformis in four conditions including high irradiance and low irradiance coupled with nitrate and ammonium (denoted as HI-NO3−, LI-NO3−, HI-NH4+ and LI-NH4+). The results showed that irradiance, nitrogen source and their interactions significantly regulated the intracellular carbon and nitrogen metabolism of G. lemaneiformis and the influence of irradiance was greater than of nitrogen source. High irradiance promoted more carbon accumulation of G. lemaneiformis, which was confirmed by higher growth rate, net photosynthesis rates and contents of soluble carbohydrate, carbon and C/N ratios. In contrast, low irradiance is conductive to nitrogen accumulation, as revealed by high contents of nitrogen, phycoerythrin, soluble protein and amino acids. Furthermore, we found nitrate coupled with high irradiance significantly promoted carbon sequestration of G. lemaneiformis, and the ammonium combined with low irradiance significantly promoted nitrogen assimilation and transformation. In addition, arginine exhibited a higher nitrogen storage capacity than phycoerythrin, as evidenced by the higher content of arginine and correspondingly higher nitrogen reserves in G. lemaneiformis under low light coupled with ammonium and nitrogen- enriched environments. Moreover, the content of proline was higher under low irradiance conditions, but its proportion among the eighteen free amino acids was upregulated by high irradiance, indicating its important role in responding to high-light aquaculture environments. These findings demonstrate that irradiance and nitrogen source influence the carbon and nitrogen reallocation of G. lemaneiformis and that the combination of these two variables can induce the production of chemical products for biotechnological, aquaculture, and nutraceutical industry.

Changes in the Content of Mobile Forms of Nitrogen in Gray Forest Soils of Opole under the Influence of Landscape Features

In a long-term stationary experiment on gray forest soils of the Vladimir Opole, the influence of agricultural technologies of cultivation of field crops on the content of mobile forms of nitrogen, their relationship with chemical and physico-chemical properties of the soil, levels of intensification have been studied. After a longterm application of agricultural technologies with an increase in the level of fertilizer application, an increase in nitrate nitrogen reserves, the degree of transition of ammonium nitrogen of the soil to the liquid phase from the humus content at the level of a strong relationship was revealed. The content of N-NH4 in the soil reduced its value. With an increase in the capacity of cation exchange, the value of this parameter changed, passing through the maximum, pHKCl - through the minimum. Changes in the humus content and physico-chemical properties of soil differences of gray forest soils have been established: gray forest plakornaya, gray forest medium-saline, gray forest medium-saline with a second humus horizon.

Sulfadiazine and phosphinothricin selection systems optimised for the transformation of tobacco BY-2 cells.

We extended the applicability of the BY-2 cell line as a model by introducing two new selection systems. Our protocol provides guidelines for optimising Basta selection in other recalcitrant models. Tobacco BY-2 cell line is the most commonly used cytological model in plant research. It is uniform, can be simply treated by chemicals, synchronised and easily transformed. However, only a few selection systems are available that complicate advanced studies using multiple stacked transgenes and extensive gene editing. In our work, we adopted for BY-2 cell line two other selection systems: sulfadiazine and phosphinothricin (PPT, an active ingredient of Basta herbicide). We show that sulfadiazine can be used in a wide range of concentrations. It is suitable for co-transformation and subsequent double selection with kanamycin or hygromycin, which are standardly used for BY-2 transformation. We also have domesticated the sulfadiazine resistance for the user-friendly GoldenBraid cloning system. Compared to sulfadiazine, establishing selection on phosphinothricin was considerably more challenging. It did not work in any concentration of PPT with standardly cultured cells. Since the selection is based on blocking glutamine synthetase and consequent ammonium toxicity and deficiency of assimilated nitrogen, we tried to manipulate nitrogen availability. We found that the PPT selection reliably works only with nitrogen-starved cells with reduced nitrate reserves that are selected on a medium without ammonium nitrate. Both these adjustments prevent the release of large amounts of ammonium, which can toxify the entire culture in the case of standardly cultured cells. Since high nitrogen reserves can be a common feature of in vitro cultures grown on MS media, nitrogen starvation could be a key step in establishing phosphinothricin resistance in other plant models.

Momento de adubação nitrogenada afeta as reservas radiculares de gramíneas tropicais

ABSTRACT Grass regrowth can reduce root mass, delaying reestablishment and grazing periods by reducing the nutrient absorption from the soil by plants. This study aimed to determine the optimal intervals for harvest and nitrogen fertilization in Urochloa brizantha cv. BRS Piatã and Megathyrsus maximus cv. BRS Quênia, as well as to investigate whether the flexibility of the fertilization time is related to the accumulation of water-soluble carbohydrates (WSC) and nitrogen in the roots. The experiment was conducted in a greenhouse, using a completely randomized design, with five treatments (nitrogen fertilization after harvest: 0, 2, 4, 6 and 8 days) and ten replicates. The nitrogen fertilization time linearly reduced the forage and root mass for the BRS Piatã, but had no effect on the BRS Quênia guinea grass. For the BRS Piatã, the WSC and starch concentrations in the roots showed a quadratic response, decreasing from harvest to day 2 and increasing until the day 8. However, the delayed fertilization led to a linear reduction in the root nitrogen content. The nitrogen fertilization time had a quadratic effect on the WSC concentration for the BRS Quênia roots. For the BRS Piatã, the nitrogen fertilization immediately after harvest improves the forage and root masses, WSC and nitrogen reserves. In contrast, the BRS Quênia exhibited a greater flexibility, concerning the nitrogen fertilization time. The interval between harvest and nitrogen fertilization is primarily depended on root mass, which influences the nitrogen accumulation in the roots.

Variation in the properties of chernozems in the Priob Plateau within the boundaries of the key site “Volodarka” (Altai Territory, Russia)

The aim of the study. To assess spatial heterogeneity of the chemical properties of the chernozems of the Near-Ob Plateau within the boundaries of the key site “Volodarka” and explain the reasons that determined the variation of the studied soil properties. Location and time of the study. Steppe zone of the northeastern part of the Near-Ob Plateau within the boundaries of the key site “Volodarka” (52°41-42' N and 83°38'E); the results of the long-term research (2007–2019) are discussed. Objects of the study. Chernozems that formed under the dry-steppe vegetation on loess deposits, as well as on different horizons of paleosols of Middle Pleistocene origin that reached surface. Methodology. Soil samples were collected to a depth of 40 cm in a continuous column at an increment of 2 to 10 cm, taking into account the visible boundaries of genetic horizons. To characterize soil chemical properties, the methods commonly used in Russian soil science studies were used. Specifically, soil organic carbon content was determined by dichromate digestion method. Results. The studied properties of chernozems, currently functioning in the same environmental conditions of the key area located on the territory of the Altai Territory, showed significant variation, as can be judged by comparing their means and coefficients of variation. The greatest fluctuations in all soil properties in all soil profiles were observed, as a rule, in the 10–20 or 20–40 cm layers, whereas in the 0–10 cm layer they changed less significantly. It was revealed that the degree of humification and humus reserves, as well as nitrogen reserves and the nitrogen enrichment of humic substances in the 0-40 cm layer, can be regarded as significant; they displayed the greatest variation in the 20–40 cm layer. Conclusions. The heterogeneity of the main properties of chernozems located in the same natural conditions of the Priob Plateau within the boundaries of the key site “Volodarka”, even within 0-40 cm layer, is most likely due to the currently present features of ancient pedogenesis. Those features do not correspond to the combination of modern soil formation conditions of the dry-steppe type: it is confirmed by the presence and extent of clearly visible Middle Pleistocene pedocomplexes in the coastal outcrops of the Ob River. Different horizons of those pedocomplexes reached the surface and had been overlayed by products of modern soil formation in layers of different thicknesses. The combination of heterogeneity of soil profiles in terms of properties, position in the coastal outcrop and their visual differentiation allowed us to conclude that the variation in the compositional characteristics and properties of the studied soils resulted from the history of the territory development, which determined the surfacing of the buried paleosols. The knowledge of the heterogeneity of soil profiles makes it possible to use the studied soil properties and characteristics of their composition for monitoring the state of modern soils, substantiating forecasts of their behavior under changing ecological conditions, as well as for identifying features of ancient pedogenesis in order to reconstruct the paleonatural environment.

Plodnost i sadržaj potencijalno toksičnih elemenata u zemljištu Mačve

By examining the fertility of Mačva soil (fluvisol, humogley, eugley, chernozem, eutric cambisol, pseudogley, luvisol, vertisol), it was found that the soils with a reaction which is favourable for growth of most crops dominate, but about 25% of the samples, mainly on Pseudogley and Luvisol, have an unfavourable, highly acidic reaction. Soil organic matter content is generally medium to high, as are the nitrogen reserves. A low content of phosphorous was found in about half of the samples, while in about 10% of soil samples, a very high phosphorous and potassium content was found, as a result of soil properties as well as inappropriate fertilization. The PTE content and natural background values are around or below the values for Central Serbia. These values are below the maximum allowed limits in domestic regulations, except for Ni, whose content increased in some samples in the alluvium of the Drina and Sava rivers and in the soil in close vicinity. Locations with values above the natural background and limit values in the legal regulations require an additional analysis of the impact on the environment.

Ratio changing of nutrients remaining reserve in the processes of diatoms and other systematic groups of algae production and mineralization in the Barents Sea

The article discusses some features of the hydrochemical and hydrobiological regimes of the marine ecosystem of the Barents Sea as a whole. A method that uses stable isotopes to calculate the consumption of the elements in the process of photosynthesis with subsequent calculation of the primary production is presented. As a result, distributions of these values in the Barents Sea were obtained. The area in the north of the sea characterized by the maximum values of silicon consumption with a remaining reserve of 8% is delimited. At the same time, the remaining reserves of phosphorus and nitrogen are 50%, although in most cases nitrogen is the limiting factor of photosynthesis in other areas of the sea. The estimated maximum volume of primary production is 7 times less than in incoming Atlantic waters. The main primary producers of pelagial in this area are diatoms, they form the main production potential, which determines the features of the hydrochemical regime of this water area.