Shoot Research Articles

Pseudoxanthomonas sp. JBR18, a halotolerant endophytic bacterium, improves the salt tolerance of Arabidopsis seedlings

Salinization of land is globally increasing due to climate change, and salinity stress is an important abiotic stressor that adversely affects agricultural productivity. In this study, we assessed a halotolerant endophytic bacterium, Pseudoxanthomonas sp. JBR18, for its potential as a plant growth-promoting agent with multiple beneficial properties. The strain exhibited tolerance to sodium chloride concentration of up to 7.5 % in the R2A medium. In vitro evaluation revealed that strain JBR18 possessed proteolytic, protease (EC 3.4), and cellulase (EC 3.2.1.4) activities, as well as the ability to produce indole-acetic acid, proline, and exopolysaccharides. Compared with the controls, co-cultivation of Arabidopsis seedlings with the strain JBR18 improved plant growth, rosette size, shoot and root fresh weight, and chlorophyll content under salinity stress. Moreover, JBR18-inoculated seedlings showed lower levels of malondialdehyde, reactive oxygen species, and Na+ uptake into plant cells under salt stress but higher levels of K+. Additionally, seedlings inoculated with JBR18 exhibited a delayed response time and quantity of salt-responsive genes RD29A, RD29B, RD20, RD22, and KIN1 under salt stress. These multiple effects suggest that Pseudoxanthomonas sp. JBR18 is a promising candidate for mitigating the negative impacts of salinity stress on plant growth. Our findings may assist in future efforts to develop eco-friendly strategies for managing abiotic stress and enhancing plant tolerance to salt stress.

Reduction of arsenic uptake in lentil through arbuscular mycorrhizal fungi

Arsenic (As) is a carcinogenic and hazardous substance that poses a serious risk to human health. The present research focused on the transport of As in seven lentil varieties developed by the Bangladesh Agricultural Research Institute (BARI) viz., BARI Mashur1, BARI Mashur 2, BARI Mashur 3, BARI Mashur 4, BARI Mashur 5, BARI Mashur 6 and BARI Mashur 7 and the role of arbuscular mycorrhizal fungi (AMFs) in mitigating As phyto-toxicity in them. The transportation of As from soil to root, shoot, and grain was lower after week 13 than in weeks 6 or 10 after lentil seedling emergence. The As accumulation in grains was higher in BARI Mashur 1 than in other test genotypes. Treatment with AMF significantly increased growth and biomass accumulation in lentil genotypes compared to non-AMF plants. Furthermore, AMF effectively reduced As concentrations in roots and shoots of lentil plants grown in 8 and 45 mg kg-1 As-contaminated soils. This study revealed a remarkable variation among the BARI-developed lentil genotypes in terms of As accumulation in plant parts. Treatment with AMF could effectively reduce plant uptake of As and mitigate As-induced phytotoxicity in lentils. The results reveal a great potential of AMF to mitigate As toxicity in lentils caused by the transport of As from soil to the shoot mass and reallocation to grains. This may enable farmers to expand lentil cultivation in As- affected areas throughout the world. Ann. Bangladesh Agric. (2023) 27 (1): 41-56

Soil gravel content and plant species configuration control vegetation restoration in Qinghai‐Tibet Plateau

AbstractSoil gravel content strongly affects ecological restoration; however, the response and mechanism of plant traits to soil gravel content under the sensitive and fragile natural environment of Qinghai‐Tibet Plateau remains unclear. Herein, soils with three gravel content (10%, 30%, 50%) in the southeastern Tibetan Plateau were selected, and three plant species (one native plants of Elymus dahuricus (Ed), and two introduced ones of Festuca elata (Fe) and Medicago sativa (Ms)) were used in seven planting patterns with different proportions (Fe, Ed, Ms, Fe + Ed (1:1), Fe + Ms (2:1), Ed + Ms (2:1), Fe + Ed + Ms (2:2:1)). Plant traits, phytochemical properties and soil stoichiometric characteristics were measured to explore the interactive effects of soil gravels and plant species on vegetation restoration. Average plant height, coverage, shoot biomass, and total biomass were most affected by plant species (F = 277–611, p < 0.01), followed by gravel content (F = 90–195, p < 0.01) and their interaction (F = 5–51, p < 0.05); root biomass was most affected by gravel content (F = 130, p < 0.01). Among plant species, shoot and root biomass, total biomass overall decreased in the order of Fe + Ed + Ms>Fe>Fe + Ms>Fe + Ed>Ms>Ms + Ed>Ed. Plant total biomass, shoot biomass, root biomass and shoot/root ratio among different soils overall decreased in the order of low> high> medium gravel contents. All plant species were restricted by soil nitrogen except for Ed and Ed + Ms (N:P > 14). In addition, increasing the gravel content in the soil will increase the soil bulk density and reduce the total soil porosity. The total soil porosity is significantly positively correlated with the average plant height, coverage, aboveground biomass, and total biomass of plants (r = 0.78–0.91, p < 0.05). The total nitrogen content, total phosphorus (TP) content, and N: P in rhizosphere soil were significantly positively correlated with the average plant height, coverage, aboveground biomass, root biomass, and total biomass of plants (r = 0.70–0.97, p < 0.05), but soil N was significantly positively correlated with aboveground biomass and total biomass (r = 0.69, 0.71, p < 0.05), and there was no significant difference in soil TP content between them. The gravel content directly affects plant growth by changing bulk density and total porosity, but the combined effect of soil nutrients and plants affects plant growth. Therefore, optimizing the configuration of soil properties (mainly nitrogen and compactness) and plant species (isecologic niche plants) is an effective strategy for ecological restoration in the Qinghai‐Tibet Plateau.

Factors influencing cadmium accumulation in plants after inoculation with rhizobacteria: A meta-analysis

Rhizobacteria have the potential to enhance phytoremediation by generating substances that stimulate plant development and influence the effectiveness of cadmium (Cd) remediation by adjusting Cd availability via metal solubilization. Furthermore, rhizobacterial inoculation affects plants' metal tolerance and uptake by controlling the expression of several metal transporters, channels, and metal chelator genes. A meta-analysis was conducted to quantitatively assess the effects of rhizobacteria on Cd accumulation in plants using 207 individual observations from 47 articles. This meta-analysis showed an average Cd concentration increase of 8.09 % in plant cells under rhizobacteria treatment. The effects of different plant-microbial interactions on the bioaccumulation of Cd in plants varied. Selecting the proper rhizobacteria-plant association is essential to affect Cd buildup in plant roots and shoots. A more extended planting period (>30 days) and a suitable soil pH (<6, 7–8) would aid in the phytoextraction of Cd from the soil. This study comprehensively and quantitatively investigated the effects of plants, rhizobacteria, soil pH, planting period, experimental sites, and plant organs on plant Cd accumulation. According to the analysis of explanatory factors, plant species, planting period, soil pH, and rhizobacteria species have a more decisive influence on Cd accumulation than other factors. The results provide information for future research on the successful remediation of soils contaminated with Cd. More investigations are required to elucidate the intricate interactions between plant roots and microorganisms.

Effect of HKUST-1 metal–organic framework in root and shoot systems, as well as seed germination

The seed germination, as well as root and shoot growth effect of HKUST-1 MOF, and its derived linear polymer ([Cu2(OH)(BTC)(H2O)]n·2nH2O) were herein examined. These effects were studied for seven higher plant species: sweet corn (Zea mays L.), black bean (Phaseolus vulgaris L.), tomato (Solanum lycopersicum L.), lettuce (Lactuca sativa L.), celosia (Celosia argentea L.), Aztec marigold (Tagetes erecta L.), and gypsophila (Gypsophila paniculata L.). The studied concentrations of MOFs were 10, 100, 500, or 1000 mg/L, enhancing the percentage of germination and growth of plants in most species. In general, the growth of the root is lower compared to the controls due to the capacity of the MOF to adsorb water and provide micronutrients such as C, O, and Cu, acting as a reserve for the plant. Shoot system growths are more pronounced with HKUST-1 compared with control, and linear polymer, due to the 3D structure adsorbs major water contents. It was found that all studied species are tolerant not only to Cu released from the material, but more evident to Cu structured in MOFs, and this occurs at high concentrations compared to many other systems. Finally, copper fixation was not present, studied by EDX mapping, banning the possibility of metallic phytotoxicity to the tested cultivars.

Microbial Consortia Versus Single-Strain Inoculants as Drought Stress Protectants in Potato Affected by the Form of N Supply

This study investigated the drought protection effects of six fungal and bacterial inoculants and ten consortia thereof on vegetative growth, nutritional status, and tuberization of potato under controlled and field conditions. It was hypothesized that microbial consortia offer improved drought protection as compared with single strains, due to complementary or synergistic effects, with differential impacts also of N fertilization management. Under NO3− fertilization, a 70% reduction in water supply over six weeks reduced shoot and tuber biomass of non-inoculated plants by 30% and 50%, respectively, and induced phosphate (P) limitation compared to the well-watered control. The P nutritional status was significantly increased above the deficiency threshold by three single-strain inoculants and eight consortia. This was associated with the presence of the arbuscular mycorrhizal fungus (AMF) inoculant Rhizophagus irregularis MUCL41833 (five cases) and stimulation of root growth (five cases). Additionally, Bacillus amyloliquefaciens FZB42 and AMF + Pseudomonas brassicacearum 3Re2-7 significantly reduced irreversible drought-induced leaf damage after recovery to well-watered conditions. However, the microbial inoculants did not mitigate drought-induced reductions in tuber biomass, neither in greenhouse nor in field experiments. By contrast, NH4+-dominated fertilization significantly increased tuber biomass under drought stress (534%), which was further increased by additional AMF inoculation (951%). This coincided with (i) improved enzymatic detoxification of drought-induced reactive oxygen species (ROS), (ii) improved osmotic adjustment in the shoot tissue (glycine betaine accumulation), (iii) increased shoot concentrations of ABA, jasmonic acid, and indole acetic acid, involved in drought stress signaling and tuberization, and (iv) reduced irreversible drought-induced leaf damage. Additional application of bacterial inoculants further improved ROS detoxification by increasing the production of antioxidants but stimulated biomass allocation towards shoot growth at the expense of tuber development. The results demonstrated that microbial consortia could increase the probability of drought protection effects influenced by the form of N supply. However, protective effects on vegetative growth do not necessarily translate into yield benefits, which can be achieved by adequate combination of inoculants and fertilizers.

Modular organization of shoot system and ontogenesis of Hedysarum branthii Trautv. &amp; C.A. Mey.

The shoot formation of Hedysarum branthii and ontogeny in natural populations on the territory of the Russian Far East were studied from the position of a modular organization. The structure of three categories of modules (elementary, universal and basic) is described. In different ecological-cenotic conditions were revealed two types of shoot. In the structure of the shoot were identifi ed the 15 types of elementary modules, which form 3 types of universal and 3 types of basic modules. The variability of the basic module is leads to the formation of three type of the life form. The life form, which consists of taproot system and elongated, ascending type of shoot is dominant of the H. branthii and in the Gamotion section of the genus Hedysarum. It has been established that a change in the life form occurs with a change in environmental conditions, namely, the altitude above sea level and the type and humidity of the substrate due to the inclusion of two types of additional adaptive elementary modules.

Effect of red and blue light supplementation on the efficacy of Noccaea caerulescens in decontaminating metals and alleviating leaching risk.

This study was conducted to investigate the impact of supplementing blue and red light on the biomass yield, metal uptake, contaminant purification, and the alleviation of leaching risks by Noccaea caerulescens, a well-known hyperaccumulator of Cd and Zn. As previously reported for the closely related Thlaspi arvense, N. caerulescens retarded the leaching of Cd and Zn but aggravated the leaching of Pb and Cu, because the species mobilized all metals in soil but only extracted Cd and Zn. Monochromic red light reduced the leaching of Pb and Cu by 13.8% and 1.3%, respectively, but simultaneously weakened Cd phytoremediation by reducing shoot biomass. Our results demonstrated that a small proportion of blue light (10%) could eliminate the negative effect of monochromatic red light on plant shoot growth. However, root biomass decreased by 14.3%, 26.2%, 21.4%, and 61.9% as the percentage of blue light increased from 10 to 100%. Noccaea caerulescens generated the most biomass and accumulated the highest metal concentrations, except for Pb, when the ratio of red to blue light was 1:1. In addition, leachate volume was significantly reduced under the 10% and 50% blue light treatments compared to other light treatments. Therefore, light supplementation with a suitable proportion of blue light can enhance metal purification by N. caerulescens and alleviate potential leaching risk during phytoremediation.

Diversity of Phyllomorphic Branches in Conifers

The structure of specialized vegetative shoots of conifers performing a trophic function has not been suffi ciently studied. The purpose of the work was to describe and classify phyllomorphic branches, as well as to identify the adaptations of conifers to the formation of such specialized trophic shoots. Phyllomorphic branches are fl attened dorsoventral shoots or systems of shoots with a non–thickened axis and opposite or regular double-row leaves. About 250 species of 42 genera of modern conifers cultivated in botanical gardens of Russia were studied. The main research method was a comparative morphological analysis of shoot systems, individual shoots and leaves. Several structural types of phyllomorphic branches have been identifi ed, each of which has its own variants: 1. Classical double-row fl at needle-shaped leaves with a thin axis (Abies, Amentotaxus, Cephalotaxus, Keteleeria, Picea, Podocarpus, Prumnopitys, Pseudotaxus, Pseudotsuga, Sequoia, Taxus, Torreya, Tsuga); 2. Phyllomorphic branches in the form of dorsiventral, branched in one plane systems of shoots (Chamaecyparis, Thuja, Glyptostrobus, Metasequoia, Taxodium); 3. Phyllomorphic branches that have phyllocladia instead of leaves (species of the genus Phyllocladus).

Synergistic effects of arbuscular mycorrhizal fungi and biochar are highly beneficial to Ligustrum lucidum seedlings in Cd-contaminated soil.

Cadmium (Cd) contamination is a widespread environmental issue. There is a lack of knowledge about the impacts of applying arbuscular mycorrhizal fungi (AMF) and biochar, either alone or in their combination, on alleviating Cd phytotoxicity in Ligustrum lucidum. Therefore, a pot experiment was conducted in a greenhouse, where L. lucidum seedlings were randomly subjected to four regimes of AMF treatments (inoculation with sterilized AMF, with Rhizophagus irregularis, Diversispora versiformis, alone or a mixture of these two fungi), and two regimes of biochar treatments (with or without rice-husk biochar), as well as three regimes of Cd treatments (0, 15, and 150mgkg-1), to examine the responses of growth, photosynthetic capabilities, soil enzymatic activities, nutritional concentrations, and Cd absorption of L. lucidum plants to the interactive effects of AMF, biochar, and Cd. The results demonstrated that under Cd contaminations, AMF alone significantly increased plant total dry weight, soil pH, and plant nitrogen (N) concentration by 84%, 3.2%, and 13.2%, respectively, and inhibited soil Cd transferring to plant shoot by 42.2%; biochar alone significantly enhanced net photosynthetic rate, soil pH, and soil catalase of non-mycorrhizal plants by 16.4%, 9%, and 11.9%, respectively, and reduced the soil Cd transferring to plant shoot by 44.7%; the additive effect between AMF and biochar greatly enhanced plant total dry weight by 101.9%, and reduced the soil Cd transferring to plant shoot by 51.6%. Furthermore, dual inoculation with D. versiformis and R. irregularis conferred more benefits on plants than the single fungal species did. Accordingly, amending Cd-contaminated soil with the combination of mixed-fungi inoculation and biochar application performed the best than either AMF or biochar alone. These responses may have been attributed to higher mycorrhizal colonization, soil pH, biomass accumulation, and biomass allocation to the roots, as well as photosynthetic capabilities. In conclusion, the combined use of mixed-fungi involving D. versiformis and R. irregularis and biochar addition had significant synergistic effects on enhancing plant performance and reducing Cd uptake of L. lucidum plants in Cd-contaminated soil.

Integration of rice apocarotenoid profile and expression pattern of Carotenoid Cleavage Dioxygenases reveals a positive effect of β-ionone on mycorrhization

Carotenoids are susceptible to degrading processes initiated by oxidative cleavage reactions mediated by Carotenoid Cleavage Dioxygenases that break their backbone, leading to products called apocarotenoids. These carotenoid-derived metabolites include the phytohormones abscisic acid and strigolactones, and different signaling molecules and growth regulators, which are utilized by plants to coordinate many aspects of their life. Several apocarotenoids have been recruited for the communication between plants and arbuscular mycorrhizal (AM) fungi and as regulators of the establishment of AM symbiosis. However, our knowledge on their biosynthetic pathways and the regulation of their pattern during AM symbiosis is still limited. In this study, we generated a qualitative and quantitative profile of apocarotenoids in roots and shoots of rice plants exposed to high/low phosphate concentrations, and upon AM symbiosis in a time course experiment covering different stages of growth and AM development. To get deeper insights in the biology of apocarotenoids during this plant-fungal symbiosis, we complemented the metabolic profiles by determining the expression pattern of CCD genes, taking advantage of chemometric tools. This analysis revealed the specific profiles of CCD genes and apocarotenoids across different stages of AM symbiosis and phosphate supply conditions, identifying novel reliable markers at both local and systemic levels and indicating a promoting role of β-ionone in AM symbiosis establishment.

The silicon regulates microbiome diversity and plant defenses during cold stress in Glycine max L.

With climate change, frequent exposure of bioenergy and food crops, specifically soybean (Glycine max L.), to low-temperature episodes is a major obstacle in maintaining sustainable plant growth at early growth stages. Silicon (Si) is a quasi-essential nutrient that can help to improve stress tolerance; however, how Si and a combination of cold stress episodes influence plant growth, plant physiology, and microbiome diversity has yet to be fully discovered. The soybean plants were exposed to cold stress (8-10°C) with or without applying Si, and the different plant organs (shoot and root) and rhizospheric soil were subjected to microbiome analysis. The plant growth, physiology, and gene expression analysis of plant defenses during stress and Si were investigated. We showed that cold stress significantly retarded soybean plants' growth and biomass, whereas, Si-treated plants showed ameliorated negative impacts on plant growth at early seedling stages. The beneficial effects of Si were also evident from significantly reduced antioxidant activities - suggesting lower cold-induced oxidative stress. Interestingly, Si also downregulated critical genes of the abscisic acid pathway and osmotic regulation (9-cis-epoxy carotenoid dioxygenase and dehydration-responsive element binding protein) during cold stress. Si positively influenced alpha and beta diversities of bacterial and fungal microbiomes with or without cold stress. Results showed significant variation in microbiome composition in the rhizosphere (root and soil) and phyllosphere (shoot) in Si-treated plants with or without cold stress exposures. Among microbiome phyla, Proteobacteria, Bacteroidota, and Ascomycota were significantly more abundant in Si treatments in cold stress than in control conditions. For the core microbiome, we identified 179 taxa, including 88 unique bacterial genera in which Edaphobacter, Haliangium, and Streptomyces were highly abundant. Enhanced extracellular enzyme activities in the cold and Si+cold treatments, specifically phosphatase and glucosidases, also reflected the microbiome abundance. In conclusion, this work elucidates cold-mediated changes in microbiome diversity and plant growth, including the positive impact Si can have on cold tolerance at early soybean growth stages - a step toward understanding crop productivity and stress tolerance.

Effect of Simulated Grazing on Morphological Plasticity and Resource Allocation of Aeluropus lagopoides

Aeluropus lagopoides, a dominant palatable species in various sabkha and coastal regions of Saudi Arabia, can withstand harsh saline environments through phenotypic plasticity. When subjected to grazing, how A. lagopoides adapt phenotypically is currently unknown. There is a breakage in the chain of study on the spatial and temporal expansion strategy of A. lagopoides plants when subjected to different grazing stresses in different saline soil habitats. A grazing experiment was conducted to investigate the phenotypic plasticity and resource allocation pattern response of A. lagopoides in different saline soils. Individual A. lagopoides rhizomes from five saline regions were grown and exposed to varied grazing treatments in the form of clipping, viz; light, moderate, and heavy grazing, as compared to a grazing exclusion control. Our results showed that heavy grazing/clipping significantly decreased the shoot system and above-ground biomass in high-saline region plants in the early season. Plant length, root length, root and shoot biomass, the number of stolons, average stolon length, leaf area, and SLA of A. lagopiodes responded significantly to grazing intensities. A. lagopoides from the Qareenah, Qaseem, and Jizan regions were more tolerant to light grazing than A. lagopoides from the Salwa and Jouf regions. Light grazing showed significantly good re-growth, especially during the late season. Light grazing decreased the synthesis of chlorophyll content. Also, A. lagopiodes reduced the risk caused by reactive oxygen species via the increased accumulation of proline content. Overall, plants adapted to different morphological and physiological strategies to tolerate different levels of grazing intensities by adapting their morphological attributes. Though heavy grazing damages the plant, light and moderate grazing can be allowed to maintain the productivity and economic benefits of sabka habitats where soil conditions are moderately saline.

Unveiling the Allelopathic Potential of Wedelia Leaf Extract as a Bioherbicide against Purple Nutsedge: A Promising Strategy for Sustainable Weed Management

Weed management is a crucial aspect of sustainable agriculture. In this study, we investigated the allelopathic potential of wedelia (Wedelia trilobata L.) leaf extract as a bioherbicide against purple nutsedge (Cyperus rotundus L.). The experiments were carried out through greenhouse experiments using a completely randomized design (CRD) with four replications. Five different concentrations were evaluated: C10% (10% wedelia extract concentration), C20% (20% wedelia extract concentration), C40% (40% wedelia extract concentration), C+ (92 mg L−1 of gallic acid), and C− (aquadest). Allelochemicals present in the wedelia leaf extract inhibited plant height, shoot number, leaf number, leaf area, root area, and total root length. The fresh weight, dry weight, and photosynthetic pigments decreased with increasing wedelia leaf extract concentrations. Malondialdehyde contents were highest when C40% was used. Additionally, peroxide activities decreased at the highest wedelia leaf extract concentration, indicating the failure of the plant’s antioxidant defense mechanism. The decrease in growth, photosynthetic pigment, and antioxidant activity indicates that wedelia leaf extract may be able to help control the growth of purple nutsedge. The results of this study could contribute to the development of a new cropping system based on the use of wedelia as a bioherbicide for sustainable agriculture.

Recovery of root hydraulic conductance and xylem vessel diameter following prolonged water deficit of maize

AbstractTo sustain crop growth following soil water deficit, it is essential to have rapid recovery of leaf gas exchange. One basis for rapid recovery would be the rapid return of root hydraulic conductance to predrought levels to support water transport to the plant shoot. In this study, transpiration and root hydraulic conductance were measured over a 9‐day recovery period following an initial water‐deficit treatment of three maize (Zea mays L.) cultivars. In addition, xylem vessel diameter was measured during the recovery period at different positions from the root tip. The initiation of recovery in the transpiration rate occurred in all three cultivars within 3 days after watering, although the root conductance and transpiration rate of one cultivar were much lower than the other two cultivars. Root conductance and vessel diameter increased more slowly than the recovery of transpiration. There was an indication that transpiration could have been limited by root hydraulic conductance only when its values were low during recovery. The relationship between hydraulic conductance and vessel diameter did not, however, indicate a Poiseuille's law relationship between the two variables. Overall, cultivar variability in recovery from water deficit of the transpiration rate and root hydraulic conductance indicates that the selection for rapid recovery of leaf gas exchange following water deficit could be an important component of genotype selection in maize breeding programs.

АБК-МЕТАБОЛИЗИРУЮЩИЕ БАКТЕРИИ ВЛИЯЮТ НА СОДЕРЖАНИЕ АБК, ИУК И ЦИТОКИНИНОВ И СНИЖАЮТ НЕГАТИВНОЕ ВЛИЯНИЕ НА РОСТ РАСТЕНИЙ САЛАТА ПРИ ЗАГУЩЕННОЙ ПОСАДКЕ

With increasing planting density, ABA accumulates in plants and their growth is inhibited even before resource deficit occurs. In this study, an attempt was made to mitigate this negative manifestation of competition by inoculating lettuce plants with ABA degrading bacteria belonging to Pseudomonas. In laboratory experiments simulating planting density by the number of plants in a pot (one and three plants), similar abilities of bacteria, P. plecoglossicida 2.4-D and P. veronii IB K11-1 to level out the decrease in plant weight in dense planting were found. Both strains reduced the content of the ABA hormone accumulating in competing plants in the soil and in the shoot, increased the IAA content in the roots and in the soil, which sharply dropped in plants with dense planting, and reduced the zeatin content in the roots. The main mechanism of the positive effect of ABA-degrading bacteria on the growth of lettuce plants is discussed as an increase in hydraulic conductivity and improvement of gas exchange as a result of a decrease in ABA in plant shoots, which was supplemented by the direct effect of bacteria on the content of auxins that activate root growth.

Dependence of quality indicators of tea leaves on soil metal ions

The article presents information on the influence of metal ions on the shoots of the Chinese tea plant - Thea sinensis L., cultivated in experimental and field conditions of the Lankaran Regional Scientific Center. The research was carried out in 2022-2023 on river sections located in the village of Khanbulan of Lankaran region, and the village of Khychu, Lerik region, which represent a subtropical zone with high humidity. Soil samples were taken and its water capacity and water-holding capacity, mechanical and organic components, as well as ions of certain metals were determined. The tea plant is very sensitive to environmental factors. Demanding on soil acidity, relative humidity, light and heat. Therefore, in our studies, to ensure the dynamic development of the tea plant, ash-yellow and ash-clay-yellow soil samples were taken. Thus, since the common soil types in this region are ash-clay-yellow and provide the presence of metal ions in the lump, this affects both the quality of the tea leaf and the antioxidant nature of the bioactive compounds of the extractive substance, as well as the color shades of tea. It is in this regard that the tea plant differs significantly from other drinks in its active influence on people’s well-being and health. For this, flavonoids are used in tea leaves - theine, catechin + theine complex, flavanol, caffeine, etc. Quantitative indicators are defined as a quantitative change in the extractive substance depending on metal-ions [1, 2, 3]. It is clear from the research that a certain metal ion is dominant for tea plants according to the nature of soil types. For the tea plant, FeO, Fe2O3, Ał2O3, MnO (iron and aluminum ions) are of special importance and are indispensable nutrients.

Silicon exhibits dose-dependent impact on barley growth

As population growth accelerates, agriculture’s significance in our lives remains paramount. However, this surge in population has led to land degradation and increased food scarcity. The impact of silicon (Si) on plants has garnered significant attention in agricultural research. This study was aimed at examining the impact of Si on barley (Hordeum vulgare) plants by administering varying concentrations (5µM, 10µM, 20µM, 50µM, 100µM, 200µM, 500µM, 1000µM) and assessing their effects on plant growth parameters, particularly root and shoot lengths, and root fresh weight. Our study employed a controlled experimental setup to observe how barley plants respond to varying concentrations of Si. The data indicates that Si concentrations up to 10µM offer advantageous effects on barley compared to the control group, suggesting its potential in bolstering agricultural productivity. Similarly, concentrations of 20µM, 50µM, and 100µM were identified as safe for plant growth, opening avenues for their agricultural utilization. However, concentrations of 500µM and 1000µM resulted in complete inhibition of plant growth, emphasizing the necessity for cautious Si application in agriculture to prevent adverse impacts on crop yields. These findings underscore the importance of fine-tuning Si concentrations in agricultural practices to optimize benefits while mitigating potential risks to plants.

Efficacy of Purpureocillium lilacinum AUMC 10149 as biocontrol agent against root-knot nematode Meloidogyne incognita infecting tomato plant.

Root-knot nematode Meloidogyne incognita is among the biotic factors which has greatly affected both the yield and the quality of the tomato crop. The egg parasitic nematode, Purpureocillium lilacinum (Pl) is considered as one of the most promising agents in controlling and overcoming this plant pathogen. The nematicidal effect of the native isolate Pl AUMC 10149 on second stage juvenile's survival and egg hatching of M. incognita at different times of exposure was tested in vitro. The obtained data showed that Pl gave a maximum percentage of J2 mortality (97.6%) and egg hatching inhibition (79.8%) after 72 hours of exposure. The potentiality of Pl as well as Bio-Nematon to control M. incognita infecting tomato was conducted using different times of application in vivo. Nine treatments with five replicates were used for such bioagents compared with the nematicide Oxamyl. Each seedling was inoculated with 1000 J2s of nematode/pot and 10 mL of Pl (1x1010 CFU/mL) or Bio-Nematon spore suspension (1x108 CFU/mL) 10mL/pot. The results indicated that the most effective treatments in reducing nematode population, number of galls and egg masses of M. incognita in plant roots was performed with treatment by Pl pre-planting and post-infection with Pl (Rf 1.9) giving a significant enhancement in plant length (64.9%), fresh weight (72.52%) and shoot dry weight (163.41%) without negatively impacting environment. Therefore, the present study confirmed that using P. lilacinum AUMC 10149 can be used as a practical supplement to environmentally friendly disease management of root-knot nematodes in Egypt.

НОРМЫ УДОБРЕНИЯ МОЛОДЫХ ПЛАНТАЦИЙ СТОЛОВОГО ВИНОГРАДА ПРИ ПОЛИВЕ СИСТЕМАМИ КАПЕЛЬНОГО ОРОШЕНИЯ

Purpose: to determine rational rates of mineral fertilizer application on young vineyards of table grape varieties with drip irrigation systems. Materials and methods. The studies were conducted in Belogorsk district of the Republic of Crimea in the foothill zone. The soils of the experimental plot are solonetzic chernozem. The studies were conducted on the Podarok Irine variety, zoned for the conditions of the Republic of Crimea. Irrigation with drip irrigation systems was carried out with a decrease in soil moisture in the 0.6 m layer to 75–80 % of minimum water capacity throughout the growing season. The calculated rate of mineral fertilizer application for the planned yield in the control variant was N80P60K60. Results. The highest indicators of plant height and vine ripening were obtained in the experimental variant with a 20 % higher dose of mineral fertilizers. The average net productivity of leaf photosynthesis per day of vegetation in the experimental variants varied from 1.1 to 1.3 g/(sq. m·day) in the first year. In the second year, this indicator changed from 2.0 to 2.7 g/(sq. m·day), and in the third year it was 1.8–2.9 g/(sq. m·day). The obtained dependencies for plant height and shoot ripening made it possible to determine that increasing the fertilizer rate on young grape plantations by more than 20% is inappropriate, since it leads to a decrease in productivity. Conclusions. The yield of the third-year grapes varied within 2.47–2.91 t/ha and was 39–64 % higher than in the variant without fertilizer application. The conducted studies made it possible to state that with an increase in the rates of mineral fertilizers by 10 and 20 %, there was an increase in the yield of the third-year grapes by 4.7 and 9.2 %, respectively. The rational rate of fertilizers on young vineyards on chernozem soils is N96P72K72 under the conditions of the foothill zone of the Republic of Crimea.