Growth Of Root System Research Articles

Effect of layered fertilizer strategies on rapeseed (Brassica napus L.) productivity and soil macropore characteristics under mechanical direct-sowing

Layered fertilization parameters affects crop root system configuration and growth distribution, which in turn affects soil pore properties and aggregate structure. Therefore, understanding the spatial distribution of the root system and soil pore space is helpful in choosing a reasonable fertilization ratio in production practice, which ensures high and stable crop yields and at the same time improves fertilizer utilization and soil health. Albeit the impact of layered fertilization ratio at varied rates on soil pore characteristics in the soil profile at a microscale level remains limited. This study quantifies the impacts of layered fertilization ratio under on rapeseed root distribution and soil pore characteristics using the root analysis system and X-ray computed tomography (XCT). A new fertilization pattern that shallow-deep layer synchronized mechanical sowing was using, rotary tillage mixed fertilization in the shallow layer and 10 cm side-deep band fertilization in the deeper layer. It set five ratios of fertilizer amounts between shallow and deep layers as 0:4 (FD), 1:3 (FL), 2:2 (FM), 3:1 (FH), and 4:0 (F0), with non-fertilization (CK) as the control treatment. The results indicated that layered fertilization effectively improved the rape root conformation and spatial distribution, significantly increased total soil porosity and moisture content, and reduced soil bulk density and resistance (P < 0.05). Additionally, root configuration is closely related to soil pore structure and crop yield. Notably, compared with other treatments, the macroscopic porosity, equivalent pore diameter, hydraulic radius and roundness of FM treatment are significantly improved, and it effectively improves the yield and quality of rapeseed. Correlation analysis showed that the root system configuration parameters were negatively correlated with soil bulk density and resistance but positively correlated with soil moisture content, and macropore morphology parameters and rapeseed yield. Our study demonstrate that layered fertilization can improved rape growth and soil macropore porosity, but its effect depends on good tillage macropore characteristics and distribution created by reasonable fertilization ratio, which provided a theoretical basis for high-yield, efficient, green, and sustainable mechanized direct-sowing production of rapeseed.

Optimal Water and Nitrogen Regimes Increased Fruit Yield and Water Use Efficiency by Improving Root Characteristics of Drip-Fertigated Greenhouse Tomato (Solanum lycopersicum L.)

The growth of root system directly affects the absorption and utilization of soil water and nitrogen, and understanding the responses of root characteristics to water and nitrogen regimes is thus crucial for optimizing water and nitrogen management. The root characteristics of each soil layer, i.e., root length, root surface area, and root volume, as well as fruit yield and water use efficiency of greenhouse tomato under drip fertigation in response to different irrigation levels and nitrogen rates were explored in northwest China. There were four irrigation levels, i.e., 50% ETC (W1), 75% ETC (W2), 100% ETC (W3), and 125% ETC (W4), where ETC is the crop evapotranspiration, and four nitrogen rates, i.e., 0 kg ha−1 (N1), 150 kg ha−1 (N2), 250 kg ha−1 (N3), and 350 kg ha−1 (N4). The results showed that reasonable irrigation and nitrogen regimes (W3N3) significantly increased fruit yield by 31.64% and root length, root surface area, and root volume by 45.03%, 61.24%, and 148.21% compare to W3N1, respectively. The promoting effect of increasing irrigation level on root characteristics increased with soil depth and had the greatest increases in root volume by 27.07%, 123.43%, and 211.47% for the 0–10, 10–20, and 20–30 cm soil layers, respectively. In addition, reducing irrigation level significantly increased the percentages of roots in the top soil by 29.71%, 26.77%, and 18.53% for root length, root surface area, and root volume, respectively. The reasonable nitrogen rate (N3) significantly increased fruit yield by 41.11%, water use efficiency by 34.42%, and root length, root surface area, and root volume by 40.42%, 41.44%, and 112.76%, respectively. The over-application of nitrogen (N4) reduced root characteristics of all soil layers, fruit yield, and water use efficiency. The promoting effect of increasing nitrogen rate on root length of each soil layer decreased with soil depth, by 71.01%, 48.96%, and 15.71% for 0–10, 10–20, and 20–30 cm soil layers, respectively. Irrigation level was the main factor dominating the root growth of each soil layer. The correlation analysis showed that fruit yield had significantly positive correlations with root characteristics in all soil layers, while water use efficiency had significantly positive correlations with the percentages of root length and root surface area in the 0–10 cm soil layer. In conclusion, rational water and nitrogen regimes achieved better fruit yield by promoting root growth of greenhouse tomato, and the water use efficiency of greenhouse tomato was improved by increasing the root percentage in the topsoil layer to alleviate the adverse effects under water stress conditions. This study reveals how irrigation volume and nitrogen application can enhance tomato yield and water use efficiency by regulating root characteristics and vertical root distribution, providing support for understanding the response of root systems to changes in soil water and nitrogen conditions.

Unveiling the Hidden Responses: Metagenomic Insights into Dwarf Bamboo (Fargesia denudata) Rhizosphere under Drought and Nitrogen Challenges.

Dwarf bamboo (Fargesia denudata) is a crucial food source for the giant pandas. With its shallow root system and rapid growth, dwarf bamboo is highly sensitive to drought stress and nitrogen deposition, both major concerns of global climate change affecting plant growth and rhizosphere environments. However, few reports address the response mechanisms of the dwarf bamboo rhizosphere environment to these two factors. Therefore, this study investigated the effects of drought stress and nitrogen deposition on the physicochemical properties and microbial community composition of the arrow bamboo rhizosphere soil, using metagenomic sequencing to analyze functional genes involved in carbon and nitrogen cycles. Both drought stress and nitrogen deposition significantly altered the soil nutrient content, but their combination had no significant impact on these indicators. Nitrogen deposition increased the relative abundance of the microbial functional gene nrfA, while decreasing the abundances of nirK, nosZ, norB, and nifH. Drought stress inhibited the functional genes of key microbial enzymes involved in starch and sucrose metabolism, but promoted those involved in galactose metabolism, inositol phosphate metabolism, and hemicellulose degradation. NO3--N showed the highest correlation with N-cycling functional genes (p < 0.01). Total C and total N had the greatest impact on the relative abundance of key enzyme functional genes involved in carbon degradation. This research provides theoretical and technical references for the sustainable management and conservation of dwarf bamboo forests in giant panda habitats under global climate change.

Engineering living root with mechanical stimulation derived from reciprocating compression in a double network hydrogel as elastic soil

The root system actively reacts to mechanical stimuli in its environment, transmitting mechanical signals to optimize the utilization of environmental resources. While the mechanical impedance created by the growth medium serves as the primary source of stimulation for the roots, extensive research has focused on the roots' response to static mechanical stimulation. However, the impact of dynamic mechanical stimulation on root phenotype remains underexplored. In this study, we utilized a low acyl gellan gum/polyacrylamide (GG/PAM) double network elastic hydrogel as the growth medium for rapeseed. We constructed a mechanical device to investigate the effects of reciprocating extrusion stimulation on the growth of the rapeseed root system. After three weeks of mechanical stimulation, the root system exhibited a significant increase in lateral roots. This branching enhanced the roots' anchoring and penetration into the hydrogel, thereby improving the root system's adaptability to its environment. Our findings offer valuable data and insights into the effects of reciprocating mechanical stimulation on root growth, providing a new way for engineering root phenotype.

Financial risk control model based on multi-swarm multi-objective root system growth algorithms

Financial risk control model based on multi-swarm multi-objective root system growth algorithms

Application of Silica Nanoparticles Improved the Growth, Yield, and Grain Quality of Two Salt-Tolerant Rice Varieties under Saline Irrigation.

Salt stress significantly reduces rice yield and quality and is a global challenge, especially in arid and semi-arid regions with limited freshwater resources. The present study was therefore conducted to examine the potential of silica nanoparticles (SiO2 NPs) in mitigating the adverse effects of saline irrigation water in salt-tolerant rice. Two salt-tolerant rice varieties, i.e., Y liangyou 957 (YLY957) and Jingliangyou 534 (JLY534), were irrigated with 0.6% salt solution to simulate high-salt stress and two SiO2 NPs were applied, i.e., control (CK) and SiO2 NPs (15 kg hm-2). The results demonstrated that the application of SiO2 NPs increased, by 33.3% and 23.3%, the yield of YLY957 and JLY534, respectively, compared with CK, which was primarily attributed to an increase in the number of grains per panicle and the grain-filling rate. Furthermore, the application of SiO2 NPs resulted in a notable enhancement in the chlorophyll content, leaf area index, and dry matter accumulation, accompanied by a pronounced stimulation of root system growth and development. Additionally, the SiO2 NPs also improved the antioxidant enzyme activities, i.e., superoxide dismutase, peroxidase, and catalase activity and reduced the malondialdehyde content. The SiO2 NPs treatment effectively improved the processing quality, appearance quality, and taste quality of the rice. Furthermore, the SiO2 NPs resulted in improvements to the rapid viscosity analyzer (RVA) pasting profile, including an increase in peak viscosity and breakdown values and a reduction in setback viscosity. The application of SiO2 NPs also resulted in a reduction in crystallinity and pasting temperature owing to a reduction in the proportion of B2 + B3 amylopectin chains. Overall, the application of silica nanoparticles improved the quality of rice yield under high-salt stress.

Application of Financial Mathematical Models Combined with Root Algorithms in Finance

Investors in the financial markets must deal with various hazards, for which they must create prudent investment portfolios and risk management plans. A multi-objective optimisation approach is proposed using the root algorithm to create a multi-objective root system growth model based on many clusters. An investment risk management optimisation model based on root system growth is built into the study using distributed decision-making. To create a multi-objective root algorithm-based portfolio optimisation model, the Markowitz mean-variance model and a multi-objective root algorithm are employed. Accordingto the findings, the multi-group multi-objective root system method has a real Pareto frontier solution that is more accessible, has a faster convergence rate, and has lower fitness values. The root algorithm’s solutions are workable, and the final risk values of 0.0105, 0.0082, and 0.4623 for the 2, 4, and 6 investment objectives are all in the low-risk class range. The optimal set of solutions discovered by the algorithm had better distributivity and convergence. The Hypervolume values for the multi-group multi-objective root algorithm were 5.5298 and 3.9628 for the dual-objective portfolio and the tri-objective portfolio of investment return costs, respectively. The findings of this study can guide the development of portfolio and risk management strategies.

Nitrogen Application Timing and Levels Affect the Fate and Budget of Fertilizer Nitrogen in the Apple-Soil System.

This study aimed to determine the effects of the nitrogen (N) application period and level on the fate of fertilizer N and the contribution of N absorption and translocation to apple organ N. Two N application periods (labeled by the 15N tracer technique in spring and summer, represented by SP and SU, respectively) and three N levels (N0, MN, and HN) were used to determine the physiological indexes and aboveground, root, and soil 15N content of 4-year-old dwarf ('Red Fuji'/M9T337) and arborized ('Red Fuji'/Malus hupehensis Rehd.) apple trees. The results showed that HN led to shoot overgrowth, which was not conducive to the growth of the apple root system (root length, root tips, root surface area, and root volume) or the improvement of root activity. The contribution of soil N to apple organ N accounted for more than 50%, and the contribution of N application in summer to fruit N was higher than that in spring. Under HN treatment, the proportion of soil N absorbed by trees decreased, while that of fertilizer N increased; however, the highest proportion was still less than 50%, so apple trees were highly dependent on soil N. Under MN treatment, fertilizer N residue was similar to soil N consumption, and soil N fertility maintained a basic balance. Under HN treatment, fertilizer N residue was significantly higher than soil N consumption, indicating that excessive N application increased fertilizer N residue in the soil. Overall, the 15N utilization rate of arborized trees (17.33-22.38%) was higher than that of dwarf trees (12.89-16.91%). A total of 12.89-22.38% of fertilizer 15N was absorbed by trees, 30.37-35.41% of fertilizer 15N remained in the soil, and 44.65-54.46% of fertilizer 15N was lost. The 15N utilization rate and 15N residual rate of summer N application were higher than those of spring N application, and the 15N loss rate was lower than that of spring N application. High microbial biomass N (MBN) may be one of the reasons for the high N utilization rate and the low loss rate of N application in summer.

The Genetic Architecture of the Root System during Seedling Emergence in Populus euphratica under Salt Stress and Control Environments

The growth of the Populus euphratica root system is of great significance for its survival under adverse environmental stress. In harsh saline-stress environments, the proportion, morphology, and functionality of the taproots and lateral roots and how they manifest specific adaptive structures, growth strategies, and potential genetic controls are still subjects for further exploration. In this study, we delve into the fundamental patterns and trade-offs of root morphology and functionality by constructing an environment-induced differential interaction equation (EDIE) to model the independent and interactive growth of the root system while considering the influence of environmental conditions. We identify 93 key QTLs in the control group and 44 key QTLs in the salt-stress group, of which 2 QTLs are significant in both environments. By constructing ODE-based QTL networks, we explore in depth how these loci regulate the growth of the root system under different environmental conditions while considering their independent direct effects and epistatic effects among loci. This study elucidates the intrinsic factors that influence the variations in taproots and lateral roots, providing crucial insights into the relationship between root morphology and functionality.

An uncertainty theory based tri-objective behavioral portfolio selection model with loss aversion and reference level using a modified evolutionary root system growth algorithm

The outbreak of uncertain events, e.g., financial crisis, regional conflict and abrupt contagion, has a significant impact on residents’ income. Hence, the wealth management and portfolio selection become more and more important. In addition, the behavioral finance believes that decision-making process of the investors not only depend on utility maximization, but also on who to compare with. It differs from the traditional finance based on rational cognitive acquiring and decision-making of agents, in this paper, we consider both investment uncertainty and investment utility with reference level for portfolio selection. First, we introduce the uncertainty theory and loss aversion utility with reference level based on behavioral finance. Then we study an uncertain multi-period portfolio selection problem. Moreover, we formulate an uncertain behavioral portfolio selection model with three objective functions for which we propose an equivalent program consisting of a main model and two auxiliary models for tri-objective optimization model. Thereafter, we use a modified evolutionary root system growth algorithm to solve the transformed models. Finally, a numerical simulation allows to show the practicability of proposed models and validity of modified algorithm.

Response to Waterlogging Stress in Wild and Domesticated Accessions of Timothy (Phleum pratense) and Its Relatives P. alpinum and P. nodosum

Timothy (Phleum pratense) is a cool-season perennial forage grass widely grown for silage and hay production in northern regions. Climate change scenarios predict an increase in extreme weather events with fluctuating periods of high rainfall, requiring new varieties adapted to waterlogging (WL). Wild accessions could serve as germplasm for breeding, and we evaluated the responses of 11 wild and 8 domesticated accessions of timothy, P. nodosum and P. alpinum from different locations in northern Europe. Young plants at tillering stage were exposed to WL for 21 days in a greenhouse, and responses in growth allocation and root anatomy were studied. All accessions produced adventitious roots and changed allocation of growth between shoot and root as a response to WL, but the magnitude of these responses varied among species and among accessions. P. pratense responded less in these traits in response to WL than the other two species. The ability to form aerenchyma in the root cortex in response to WL was found for all species and also varied among species and among accessions, with the highest induction in P. pratense. Interestingly, some accessions were able to maintain and even increase root growth, producing more leaves and tillers, while others showed a reduction in the root system. Shoot dry weight (SDW) was not significantly affected by WL, but some accessions showed different and significant responses in the rate of production of leaves and tillers. Overall correlations between SDW and aerenchyma and between SDW and adventitious root formation were found. This study identified two wild timothy accessions and one wild P. nodosum accession based on shoot and root system growth, aerenchyma formation and having a root anatomy considered to be favorable for WL tolerance. These accessions are interesting genetic resources and candidates for development of climate-resilient timothy varieties.

Impact of Fusarium Crown Rot on Root System Area and Links to Genetic Variation within Commercial Wheat Varieties

Fusarium crown rot (FCR), caused by the fungal pathogen Fusarium pseudograminearum (Fp), is a major constraint to cereal production worldwide. The pathogen restricts the movement of solutes within the plant due to mycelial colonisation of vascular tissue. Yield loss and quality downgrades are exacerbated by this disease under water stress conditions. Plant root systems are adaptive and can alter their architecture to optimise production in response to changes in environment and plant health. This plasticity of root systems typically favours resource acquisition of primarily water and nutrients. This study examined the impact of FCR on the root system architecture of multiple commercial bread and durum wheat varieties. Root system growth was recorded in-crop in large transparent rhizoboxes allowing visualization of root architecture over time. Furthermore, electrical resistivity tomography was used to quantify spatial root activity vertically down the soil profile. Results demonstrated a significant reduction in the total root length and network area with the inoculation of FCR. Electrical resistivity measurements indicated that the spatial pattern of water use for each cultivar was influenced differently from infection with FCR over the growing season. Specifically temporal water use can be correlated with FCR tolerance of the varieties marking this investigation the first to link root architecture and water use as tolerance mechanisms to FCR infection. This research has implications for more targeted selection of FCR tolerance characteristics in breeding programs along with improved specific varietal management in-crop.

The effect of live chlorella suspension on the growth and development of grafted seedlings of Cabernet Sauvignon grapes

One of the ways to grow high-quality grafted grape seedlings is to use modern, environmentally friendly biologically active preparations. Today, such preparations include live chlorella suspension. Its use in grape nursery is a new and relevant technological method of growing planting material. The aim of the study was to show the effect of live chlorella suspension on the realization of the biological potential of grapevines, with the subsequent production of high-quality grafted grape seedlings. Field (recording of plant growth and development), laboratory (determination of quantitative and qualitative parameters of plants) and statistical (confirmation of the reliability of the results) research methods were used. The obtained results showed that for soaking rootstock and scion components it is advisable to use the strain Chlorella vulgaris Beijer, dilution 1:5, soaking should be carried out for 72 hours – rootstock components, 18 hours – scion components; for irrigation of grape garden plot it is advisable to use the strain Chlorella vulgaris Beijer. + Ge, dilution 1:5, it was carried out immediately after planting scions and three times during the growing season – in June, July, and August. The use of these strains of live chlorella suspension allowed obtaining a higher yield of standard seedlings from the garden plot, the plants had a well-developed root system and annual growth. Compared to the control, which was water, the total number of roots increased. Plants in these variants were also characterized by increased growth of the aboveground part. Indicators of total and mature growth, which characterize the overall development of grafted grape seedlings, were in the range of 687.1-773.2 cm3 (total growth volume), 337.9-386.6 cm3 (mature growth volume), while 730.1 and 362.6 cm3 , respectively, in the control. The records of the output of standard seedlings from the garden plot also showed the advantage of using a suspension of live chlorella (an increase of 19.0-21.0%) compared to water. The above technological methods allow obtaining high-quality grape seedling products and can be a promising alternative for more sustainable and environmentally friendly agricultural methods

Micro-nano oxygenated irrigation improves the yield and quality of greenhouse cucumbers under-film drip irrigation

To study the influence mechanism of micro-nano oxygenated irrigation (MNOI) on greenhouse fruit cucumber in arid and semi-arid cold regions, the yield and quality of greenhouse fruit cucumber were evaluated and verified based on 2 years of observation data. Taking fruit cucumber in Ningxia solar greenhouse as the research object, three dissolved oxygen (DO) levels of MNOI (DO; 6, 7.5, and 9 mg L−1, O1, O2, and O3, respectively) and non-oxygenated irrigation (CK, 4 mg L−1) were set up as the control treatment. Through comparative design, the influence mechanism of different levels of aerobic irrigation on the yield and quality of greenhouse fruit cucumber was studied. The main indicators of fruit cucumber yield and quality increased with dissolved oxygen in irrigation water from 4 to 9 mg L−1. In spring–summer (autumn–winter), compared with CK, the leaf area index (LAI) and net photosynthetic rate (A) increased by 28.83% (28.77%) and 44.90% (35.00%), respectively, and Vitamin C, soluble protein, soluble sugar, soluble solids and total acid content increased by 100.00% (51.88%), 37.78% (61.11%), 34.17% (54.17%), 37.07% (78.72%) and 26.92% (30.67%) respectively, while nitrate content decreased by 44.88% (51.15%), and dry matter accumulation (DMA), soil respiration rate (SRR), microbial carbon (MC), and microbial nitrogen (MN) increased by 49.81% (127.25%), 55.22% (110.34%), 117.50% (90.91%) and 70.37% (74.42%) respectively, and yield, irrigation water use efficiency (IWUE) and soil oxygen content (SO) increased by 22.47% (28.04%), 22.39% (28.05%) and 33.21% (35.33%) respectively. A model of DO in irrigation water and SO was established and the applicability of the model was verified with an average relative error of 2% (less than 5%). MNOI increased SO and soil enzyme activity, enriched soil microorganisms, improved soil microenvironment, promoted water nutrient uptake and growth of root system, increased chlorophyll, photosynthesis and DMA, which improved fruit cucumber yield and quality, and the better DO concentration in irrigation water is 9 mg L−1. The research results provide theoretical support for regulating soil water, fertilizer and air environment, and at the same time, provide feasible ways to improve the quality and efficiency of crops in arid and semi-arid cold regions.

Synthesis and application of super absorbent polymers synthesized with ammonia solution and diatomaceous earth with low toxic residues

Water-soluble harmful components that remained in SAPs pose potential risks to crop growth, resulting in decreased seed germination rate, reduced yield, and inhibited root system growth. These factors restrict its widespread use in agriculture and forestry. In this study, a new type of super absorbent polymers (AD-SAP) with low residual acrylic acid and sodium ions was synthesized by using ammonia solution instead of strong alkali sodium hydroxide for neutralization and adding modified diatomaceous earth to improve the grafting efficiency. The prepared samples were characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and energy-dispersive X-ray spectroscopy (EDS), and the influence of the dosage of acrylic acid and ammonia solution used for preparation on the residual content of water-soluble harmful components in AD-SAPs was investigated. When 28% of acrylic acid, 24% of ammonia solution, and 5% of diatomaceous earth were used for synthesis, the residual acrylic acid content in AD-SAP was 0.03%, and the sodium ion content was reduced to 0.12 g/kg, which is much lower than the three commercially available SAPs. However, its water-absorption capacity has not decreased and its salt resistance has improved. The water absorption ratio of AD-SAP is 578g/g, and the salt-absorption ratio is 87 g/g. Pot experiments showed that AD-SAP eliminated the adverse effects of commercial SAPs on crop growth. The research provided technical support for the production of SAPs, and offer scientific guidance for how to mitigate the adverse effects of SAPs on crop growth.

Assessment of tractor track width compatibility with crop inter-row spacing

Various factors can exert detrimental effects on crop growth and development, among which the influence of the machinery's running gear within the machine-tractor unit stands out, particularly within the soil vicinity encompassing the plant's root system. As a result, the area of soil compaction arising from tractor wheel pressure increasingly covers the plant's protective zone. This poses challenges for both root system growth and development, as well as the optimal uptake of soil nutrients, often leads to plant damage or even trampling. Presently, there is no universally accepted metric for assessing the compatibility between tractor track width and the specific inter-row spacing under cultivation. (Research purpose) Development of an indicator to assess the compatibility of the tractor track width with the cultivated inter-row spacing. (Materials and methods) The analysis demonstrates that the level of compatibility of the tractor track to the crop inter-row spacing is determined based on the dimensions of the crop spacing, the tractor track width, the protective zone outlined by agrotechnical standards, the deviation of the wheel trajectory from the axis of row symmetry, and tire size. (Results and discussion) An analytical correlation has been derived to determine the level of compatibility between tractor track width and crop inter-row spacing, using the context of cotton cultivation as an illustrative example. It has been revealed that among the serial tractors utilized within cotton farms across the region, full-fledged operational performance is exclusively achieved when row spacings measure 60 and 90 centimeters. In contrast, the utilization of this machinery on row spacings of 70 and 76 centimeters leads to detrimental outcomes such as row trampling and plant damage. (Conclusions) The viability of the developed indicator has been determined and validated. The improvement of the tractor propulsion system should be aimed at devising a technical solution that facilitates seamless adjustment of track width over a broad spectrum, thus allowing for adaptability to diverse row spacing requirements.

Importance of brassinosteroids for mitigating water stress in sorghum

The objective of the present study was to assess the mitigating effect of brassinosteroids on water stress caused by different water supplies (water deficit and excess water) in sorghum. The experiment was conducted at the experimental farm of the State University of Goias, South Campus, in Ipameri, GO, Brazil. A completely randomized design was used, in a 2×5 factorial arrangement with 4 replications. The plants were grown under five water supplies (25%, 50%, 100%, 200%, and 400% of the evapotranspiration) and treatments with and without brassinosteroid (0.1 mg L-1) application at 30.0 mL plant-1, carried out in three moments (at 45, 47, and 49 days after emergence). The tests conducted in pots limited the root system growth by the volume of the container, but despite these conditions, sorghum plants treated with brassinosteroids presented higher root system development and plant height, denoting that the brassinosteroids have the potential for mitigation of water deficit at field level. The main mechanism of tolerance to drought of sorghum is its high stomatal sensitivity, which rapidly reduces transpiration and minimizes the plant dehydration under water deficit

ЭНЕРГЕТИЧЕСКАЯ МАТЕМАТИЧЕСКАЯ МОДЕЛЬ ОПРЫСКИВАТЕЛЯ

The research was carried out in order to develop an energy mathematical model of a plant protection unit with a trailed sprayer, which makes it possible to optimize the parameters and operating modes, taking into account their influence on the size and loss of crop yield. For comparison with the tendencies of changes in the parameters of sprayers established in practice, computational experiments were performed using the developed mathematical model. The object of study is an analogue of MTZ-82 tractor, the main parameters of which (mass, engine power, kinematic length, etc.) can be changed, an analogue of a trailed sprayer with variable parameters (width, operating speed, tank volume, drawbar length, location of the center of mass, profile width and support wheel diameter, etc.). The optimization criterion was composite and included the sum of direct and indirect energy costs during the operation of the unit, taking into account the energy of the crop lost due to deviations from the optimal parameters and operating modes of the sprayer. Incorrect choice of unit parameters leads to yield losses, resulting from its decrease due to a violation of the deadline for performing a technological operation to protect crops from weeds, trampling down part of the crops by the unit's movers during processing, especially if there is no possibility of turning outside the field, due to soil compaction in the zone of growth and development of plant root systems. Computational experiments carried out using the developed energy mathematical model showed that an increase in sprayer coverage from 16 to 32 m at an aggregate speed of 12 km/h leads to a decrease in total energy costs from 3250 MJ/ha to 1692 MJ/ha, an increase in the unit speed from 7 to 12 km/h, with a working width of 32 m reduces the total energy costs from 1971 to 1692 MJ/ha. Reducing the width of the sprayer wheel tire profile from 0.6 to 0.2 m is accompanied by a decrease in total energy costs from 2793 MJ/ha to 1692 MJ/ha.

Isolation of cadmium-resistance and siderophore-producing endophytic bacteria and their potential use for soil cadmium remediation

Endophyte-assisted phytoremediation is an emerging technique for soil heavy metals (HMs) remediation and has become a research focus in the world because of the benefits of endophytes on plant growth and uptake of HMs. In this study, multifunctional endophytic bacteria strains were isolated and screened, and the feasibility of these strains for soil cadmium (Cd) remediation was investigated by soil incubation experiments and pot experiments. All endophytic bacteria were isolated from the roots of woody plants grown on Cd-contaminated soil. Seven endophytic bacteria strains had capacities to tolerate Cd toxicity and produce siderophores, and sequence analysis of the 16S rRNA gene classified these strains as belonging to the genera Burkholderia, Pseudomonas, Pantoea, and Herbaspirillum. All strains were able to produce hydroxamate siderophores (32.40%–91.49%) and had three or more plant growth promoting properties such as phosphorus solubilization, nitrogen fixation, indole acetic acid and 1-aminocyclopropane-1-carboxylate deaminase production. They were all strongly resistant to Cd2+ toxicity, with the minimum inhibitory concentration in LB medium ranging from 1.5 mM to 9.0 mM. Except for strain Burkholderia contaminans JLS17, other strains showed decreasing removal rates within continuously elevated Cd2+ concentration of 10–100 mg L−1. Compared with the uninoculated treatment, the inoculation of strains B.contaminans JLS17, Pseudomonas lurida JLS32, and Pantoea endophytica JLS50 effectively increased the concentration of acid-soluble Cd and decreased the concentration of reducible, oxidizable, and residual Cd in the soils of different Cd contamination levels. In pot experiments, inoculation of strains JLS17 and YTG72 significantly (p < 0.05) promoted the growth of above-ground parts and root system of slash pine (Pinus elliottii) under Cd stress. This study provides a valuable biological resource for endophyte-assisted phytoremediation and a theoretical basis for the application of endophytic bacteria for remediation of Cd-contaminated soil.

Transcription factors KANADI 1, MYB DOMAIN PROTEIN 44, and PHYTOCHROME INTERACTING FACTOR 4 regulate long intergenic noncoding RNAs expressed in Arabidopsis roots.

Thousands of long intergenic noncoding RNAs (lincRNAs) have been identified in plant genomes. While some lincRNAs have been characterized as important regulators in different biological processes, little is known about the transcriptional regulation for most plant lincRNAs. Through the integration of 8 annotation resources, we defined 6,599 high-confidence lincRNA loci in Arabidopsis (Arabidopsis thaliana). For lincRNAs belonging to different evolutionary age categories, we identified major differences in sequence and chromatin features, as well as in the level of conservation and purifying selection acting during evolution. Spatiotemporal gene expression profiles combined with transcription factor (TF) chromatin immunoprecipitation (ChIP) data were used to construct a TF-lincRNA regulatory network containing 2,659 lincRNAs and 15,686 interactions. We found that properties characterizing lincRNA expression, conservation, and regulation differ between plants and animals. Experimental validation confirmed the role of 3 TFs, KANADI 1, MYB DOMAIN PROTEIN 44, and PHYTOCHROME INTERACTING FACTOR 4, as key regulators controlling root-specific lincRNA expression, demonstrating the predictive power of our network. Furthermore, we identified 58 lincRNAs, regulated by these TFs, showing strong root cell type-specific expression or chromatin accessibility, which are linked with genome-wide association studies genetic associations related to root system development and growth. The multilevel genome-wide characterization covering chromatin state information, promoter conservation, and chromatin immunoprecipitation-based TF binding, for all detectable lincRNAs across 769 expression samples, permits rapidly defining the biological context and relevance of Arabidopsis lincRNAs through regulatory networks.