Plant Root System Research Articles

Peculiarities of plant adaptation of interspecific hybrid Betula ex vitro

Microclonal propagation as one of the methods of biotechnology allows obtaining genetically homogeneous plants during the year from a minimum amount of donor material. Adaptation of plants ex vitro to environmental conditions is the final and important stage of microclonal propagation. The purpose of the study is to determine the optimal mode of plant adaptation of triploid interspecific hybrid Betula ex vitro to environmental conditions. Biotechnological (microclonal propagation) and statistical (arithmetic mean, standard error, one-way analysis of variance (ANOVA)) methods were used for research. The study was carried out in the research of Plant Biotechnology Laboratory of the Separated Subdivision of National University of Life and Environmental Sciences of Ukraine “Boyarka Forest Research Station” during 2019-2023. According to research, the MS nutrient medium with the addition of 0.25 mg∙l -1 of kinetin stimulated the active proliferation of microshoots and root system. Optimum plant development took place on the nutrient medium vitro for a 25-30- day cycle of cultivation, which contributed to successful adaptation to environmental conditions. The proportion of adapted Betula ex vitro hybrid plants on agroperlite substrate was more than 60% for 30 days. Significant plant viability (more than 80%) was obtained under the conditions of preliminary exposure of the plant root system in auxin solution (1.0 mg/lIAA, 1.0 mg/l NAA, 1.0 mg/lIBA) for 25-30 minutes followed by daily spraying of leaves with 20% glycerin for 15-20 days. Adapted plants had typical pigmentation without signs of chlorosis and vitrification. In the spring, the survival rate of plants under environmental conditions was more than 80% and indicated a high level of adaptability after in vitro. The developed protocol for the adaptation of the Betula ex vitro hybrid allows obtaining high plant survival in environmental conditions. The practical value of the research is obtaining plants adapted to environmental conditions ex vitro, which in the future can be used to qualitatively enrich the range of artificial plantings in settlements

Physiological and Morphological Implications of Using Composts with Different Compositions in the Production of Cucumber Seedlings.

Compost has a broad application in terms of the improvement of the soil properties. This research work was conducted to present the molecular implications of using compost obtained from different substrates to improve soil parameters for cucumber seedlings cultivation. In the experiment, the following compost mixtures were used: sewage sludge (80%) + sawdust (20%); sewage sludge (40%) + sawdust (10%) + biodegradable garden and park waste (50%); biodegradable garden and park waste (90%) + sawdust (10%); sewage sludge (80%) + sawdust (20%) + Eisenia fetida; sewage sludge (40%) + sawdust (10%) + biodegradable garden and park waste (50%) + Eisenia fetida; biodegradable garden and park waste (90%) + sawdust (10%) + Eisenia fetida. The final substrate compositions consisted of compost mixtures and deacidified peat(O) (pH 6.97; Corg content-55%, N content-2.3%), serving as a structural additive, in different mass ratios (mass %). The produced plants underwent biometric and physiological measurements as well as enzymatic analyses of stress markers. Based on the conducted studies, it has been found that the substrate productivity depends not only on the content of nutrient components but also on their structure, which is moderated by the proportion of peat in the substrate. The most effective and promising substrate for cucumber seedling production was variant 2 (I), which consisted of 25% compost from sewage sludge (40%) + sawdust (10%) + biodegradable garden and park waste (50%) and 75% deacidified peat. Despite the richness of the other substrates, inferior parameters of the produced seedlings were observed. The analysis of the enzymatic activity of stress markers showed that these substrates caused stress in the plants produced. The study's results showed that this stress was caused by the presence of Eisenia fetida, which damaged the developing root system of plants in the limited volume of substrate (production containers). The adverse influence of Eisenia fetida on the plants produced could possibly be eliminated by thermal treatment of the compost, although this could lead to significant changes in composition.

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.

Arbuscular-Mycorrhizal Symbiosis in Medicago Regulated by the Transcription Factor MtbHLHm1;1 and the Ammonium Facilitator Protein MtAMF1;3.

Root systems of most land plants are colonised by arbuscular mycorrhiza fungi. The symbiosis supports nutrient acquisition strategies predominantly associated with plant access to inorganic phosphate. The nutrient acquisition is enhanced through an extensive network of external fungal hyphae that extends out into the soil, together with the development of fungal structures forming specialised interfaces with root cortical cells. Orthologs of the bHLHm1;1 transcription factor, previously described in soybean nodules (GmbHLHm1) and linked to the ammonium facilitator protein GmAMF1;3, have been identified in Medicago (Medicago truncatula) roots colonised by AM fungi. Expression studies indicate that transcripts of both genes are also present in arbuscular containing root cortical cells and that the MtbHLHm1;1 shows affinity to the promoter of MtAMF1;3. Both genes are induced by AM colonisation. Loss of Mtbhlhm1;1 expression disrupts AM arbuscule abundance and the expression of the ammonium transporter MtAMF1;3. Disruption of Mtamf1;3 expression reduces both AM colonisation and arbuscule development. The respective activities of MtbHLHm1;1 and MtAMF1;3 highlight the conservation of putative ammonium regulators supporting both the rhizobial and AM fungal symbiosis in legumes.

Rice-inspired oriented copper fiber wick with excellent capillary performance for ultra-thin vapor chamber

In response to the current trend of thermal management systems for microelectronic products, ultra-thin vapor chambers (UTVCs) have become an emerging hotspot. Currently, there is an urgent challenge to design of high-performance capillary wicks for use in limited spaces for UTVCs. In this study, an ultra-thin copper fiber wick (UTCFW), inspired by rice plants, was proposed and prepared by the limited fiber sintering and hydraulic pressure methods. By simply varying the fiber length in the mould, it was possible to prepare an UTCFW with ordered orientation similar to the developed root system of the rice plant. A chemical treatment was used to develop micro- and nano-scale structure on the surface of the UTCFW, similar to hairs on roots of the rice plant, which makes the UTCFW exhibit superhydrophilic properties. After optimization, the capillary factor M of the most ordered sample with 80 mm fibers (L80) was 1.254 μm, which was 567 % times that of the poorly ordered with 5 mm fibers (L5). In short, the bioinspired UTCFW had both excellent wettability and capillary performance. This study demonstrated the preparation of a high-performance and cost-effective UTCFW for improving the thermal performance of UTVCs.

ВЛИЯНИЕ ПРЕПАРАТА «РИБАВ-ЭКСТРА» НА РАЗВИТИЕ РАСТЕНИЙ ЕЖЕВИКИ СОРТА ФРИДОМ ПРИ АДАПТАЦИИ

The paper presents data on the use of the growth regulator “Ribav-Extra” at the stage of blackberry adaptation. Blackberry microplants of the Freedom variety have a high adaptive capacity. In the variant with “Ribav-Extra”, 98 % of plants adapted, in the control variant - 95 %. It has been established that treatment with a growth regulator promotes the development of the plant root system. After treatment with the preparation, 10 roots or more were formed on the plant, in the control variant, on average, 4-5 roots were formed on the plant. The bulk of the roots had a length of more than 4 cm (up to 7 cm), in the control variant 2-4 cm.

NEMATODES AND ROOT SYSTEM ARE AFFECTED BY RHIZOBACTERIAL CONSORTIUM IN THE THIRD GENERATION OF COMMERCIAL BANANA PLANTS

Rhizobacteria has shown promising results in managing nematodes and improving the root system of banana plants. However, their effects on commercial banana plants in different generations remain unclear. In this study performed under field experiment, we evaluated the effect of three types (injection, edaphic and foliar) of a local rhizobacterial consortium application on the system root, nematode populations, and their damage in the third-generation plants. Only mother and daughter plants were treated twice with the rhizobacteria. Plants not treated with rhizobacteria constituted the control treatment. Our results show that rhizobacteria affect different underground tissues and nematodes in third-generation banana plants. Helicotylenchus spp., Meloidogyne spp., Pratylenchus spp., Radopholus similis, and Rhabditis spp. were the nematodes found in banana roots. R. similis population and the damage in the root system of banana plants were reduced significantly by the rhizobacteria edaphic application. The application of rhizobacteria could be a sustainable management strategy over time to improve the root system and suppress nematodes, and their damage in commercial banana plants.

INFLUENCE OF RHISOSPHERIC BACTERIA ON THE PRODUCTIVITY OF WHEAT PLANTS AND THE INPUT OF ELEMENTS FROM POLLUTED SOILS

The results of a vegetation experiment on the humus horizon of soddy-podzolic sandy loamy soil (Albic Retisol), which was contaminated with heavy metals as a re sult of sewage sludge as a fertilize r, are presented. The soil was used for growing vegetables and forage grasses but has been abandoned for the last 10 years. In the experiment, the effect of rhizospheric bacteria of the genus Pseudomonas on biomass and the entry of micro- and heavy metals into the vegetative organs and root system of spring wheat plants was studied. Under the influence of inoculation with bacteria, the biomass of wheat plants increased by 10–12% and the content of the main macro- and microelements in plants changed. The content of Ca, K, Mg, Na and P decreased by 1,5–2 times in the vegetative part of wheat plants inoculated with P. fluorescens 21 and P. putida 23. The content of macroelements in wheat roots changed little, but the ratio between the content of elements increased in roots and vegetative parts of plants. The distribution of the content of trace elements and HMs was much more contrasting: the content of Cd in the roots of wheat plants exceeded that in the vegetative part of plants by 9 times without treatment with bacteria and by 18 and 11 times aft er inoculation with P. fluorescens 21 and P. putida 23, and in variants with P. fl uorescens 20 by 7 times. A decrease in the content of Cd in the vegetative part of wheat plants was noted, by 2 times upon inoculation with P. fluorescens 21 and by 1,5 times for variants with P. putida 23. The content of Zn in the aerial parts of plants also decreased upon inoculation with P. fluorescens 21 and by 1,8 times for variants with and P. putida 23 by 1,4 times. An increase in the ratio of the content of elements in the roots and vegetative mass of plants indicates an increase in the resistance of plants to the toxic effect of heavy metals and the barrier function of the roots.

Isolation and Characterization of Plant Growth Promoting Rhizobacteria form Raphanus sativus (Radish)

Rhizobacteria are present in rhizosphere region of plant root system, which enhance the plant growth by various way like biological nitrogen fixation, siderophore production, phosphate solubilization and phytohormone production. The soil samples were collected from rhizosphere region of Raphanus sativus, after enrichment rhizobacteria was isolated by serial dilution method, diluted sample were spread on respective solid agar media plates. Isolated rhizobacteria was identify by biochemical and molecular characterization methods. The isolated PGPRs was Bacillus subtilis which was showed phosphate solubilization activity and they were enhanced 30% more green gram seed germination. The method of current research is screening, isolation and biochemical characterization of rhizobacteria form rhizosphere region of Raphanus sativus. Phosphate solubilizing bacteria, solubilized the unavailable phosphate and provide to plant. The main purpose of this research paper is to widen the understanding of the role of phosphate solubilizing bacteria in crop production as biofertilizers.

Unlocking the potential of rhizobacteria in Moroccan vineyard soils: Biocontrol of grapevine trunk diseases and plant growth promotion

Rhizospheric bacteria isolated from the root system of Vitis vinifera plants in Morocco were evaluated for their activities against fungi associated with grapevine trunk diseases namely Diplodia mutila, Neoscytalidium dimidiatum, Trichothecium roseum, and Neopestalotiopsis vitis. Those pathogens cause grapevine decline and impede growth and are known as the greatest threat to production worldwide. Among a collection of 196 rhizobacteria, twenty-four isolates exhibited potential antifungal activity against all the tested fungal pathogens. Based on the partial 16S rDNA genes, different genera were identified namely Bacillus, Pseudomonas, Achromobacter, Ensifer, and Brucella. In particular, Bacillus halotolerans (JFM-64 and JMS-14), Pseudomonas koreensis (JRSK-45), and Ensifer adhaerens (JRSK-84) were found to be the most effective strains. Furthermore, the potential of bacterial isolates to promote plant growth was assessed. The funding revealed that of twenty-four antagonist rhizobacteria, seventeen displayed protease and chitinase production, while fifteen, thirteen, and twelve bacteria demonstrated the production of amylase, cellulase, and pectinase respectively. Furthermore, thirteen bacterial isolates produced hydrocyanic acid (HCN), sixteen isolates harbor the ability to solubilize tricalcium phosphate and seventeen were able to produce siderophores and indole acetic acid (IAA). The results of the current study showed that the most effective bacterial isolates could exhibit traits other than Plant Growth-Promoting Rhizobacteria (PGPR). Our results showed that the bacterization of B. napus seedlings with the selected bacteria improved plant growth when compared to untreated controls. Autoclaved grape wood assays were used to further confirm the in vitro results. The growth of Diplodia mutila, Neopestalotiopsis vitis, Neoscytalidium dimidiatum, and Trichothecium roseum was effectively reduced by rhizobacterial isolate Pseudomonas koreensis (JRSK-45) by 97.31, 97.14, 94.17, and 91.91%, respectively. This study highlights the potential of specific rhizobacteria as a promising approach to controlling fungal trunk pathogens associated with grapevine decline.

Response of the Anchoring Performance at Betula platyphylla’s Root–Soil Interface to Cyclic Loading

In dealing with issues such as soil erosion and slope instability, plant roots enhance the shear strength of the soil mass through their anchoring effect. However, in nature, cyclic loads such as flash floods and blizzards indirectly impose fatigue effects on plant root systems. To explore the impact of cyclic loads on the anchoring capacity of plant roots, this paper selects the roots of Betula platyphylla as the research object and uses a monotonic load and cyclic load as two loading modes. Under different loading amplitudes (25%, 50%, and 75%), root diameters and burial depths (50 mm, 100 mm, and 150 mm), and soil moisture contents (11.85%, 13.85%, and 15.85%), the effects of each factor on the anchoring capacity of the roots under cyclic loading are analyzed. The results showed that the root–soil interface exhibited two failure modes under different cyclic load amplitudes, and the cyclic load significantly reduced the maximum friction of the root–soil interface. As the cyclic load amplitude increased (from 25% to 75%), the hysteretic curve envelope area increased, and the growth rate of cumulative residual slip changed from decreasing to decreasing and then increasing. A good correlation was found between cumulative residual slip and the number of loading cycles, and the three characteristic slips were correlated with loading amplitude but not significantly with diameter. The increase in soil moisture content, root embedment depth, and diameter led to an increase in the ratio of the two maximum friction forces. It was shown that a certain degree of plasticity exists at the root–soil interface to resist environmental stresses in nature. At high fatigue stress levels, the root–soil interface is more nonlinear, and as the load amplitude increases, more energy is dissipated, and bond damage between the root–soil interface becomes more pronounced. The root–soil interface gradually degraded under long-term cyclic loading, whereas the increase in root depth and soil water content could resist the negative effect of cyclic loading on anchorage capacity, and the resistance effect became more and more obvious with the increase in diameter.

Phenolic compounds of sorghum [Sorghum bicolor (L.) Moench] and their allelopathic effect

Purpose. To establish the quantitative composition of phytochemicals containing in vegetative and generative organs of sugar sorghum hybrids with high and medium sugar content ‘Sugargraze ARG’ (Argentina), ‘Sioux’ and ‘Mohawk’ (USA) and ‘Ananas’ and ‘Medovyi’ (Ukraine) and their allelopathic effect
 Methods. Allelopathic, physiological-biochemical, agrochemical and statistical methods were used. The content of phytochemicals in the vegetative and generative organs of the studied sugar sorghum hybrids was determined by the extraction method.
 Results. A high concentration of sorghum phenolic substances in the seeds at the mature plant stage was found. However, their concentration was species specific and depended on their quantitative component in the process of morphogenesis of vegetative and generative organs of sorghum of different genetic origin. The analysis of the total content of phytochemical compounds in the studied hybrids showed an increase in their number at the end of the vegetation season. The research was conducted in vitro. The manifestation of phenolic compounds was observed through manifestation of the allelopathic effect of cultivated sorghum plants. It was found that on the 7th day of cultivation, the plants actively secreted phenolic compounds; the increase in the number of leaves and the height of plants in hybrids did not change and amounted to 3–5 and 1.6–2.0 cm, respectively. On the 14th day of the experiment, the phenolic spots grew significantly, and yellowing of the lower leaves appeared. In the process of morphogenesis of sorghum plants (during 21 days), a more intense release of phenolic compounds led to suppression and slowing down of growth and subsequently to the death of the clone, regardless of the genetic origin of the hybrids. Phenolic compositions also influenced the formation of the root system of cultivated sorghum plants. A significant decrease in the number of lateral roots and the length of the root system was noted in all studied hybrids.
 Conclusions. The highest content of phenolic compounds was found in the seeds (grain) and stems of the studied sorghum hybrids. Thus, the quantitative composition of glycosides and tannins was 34–39 and 5.5–6.9 %, respectively, in the seeds and 25–29 and 0.3–1.4 %, respectively, in the stems of the studied hybrids. The highest content of hydroxycinnamic acids (from 7 % to 14 %) was found in the leaves of the studied sorghum hybrids. Phenolic compositions under in vitro conditions cause stress, which slows down the growth and development of cultivated plants, and subsequently lead to the death of clones.

Comparative environmental and economic life cycle assessment of phytoremediation of dredged sediment using Arundo Donax, integrated with biomass to bioenergy valorization chain

The economic and environmental life cycle assessment (LCA) was integrated into a laboratory-based experiment to evaluate the feasibility and sustainability of phytoremediation of chloride-rich marine dredged sediment, using perennial reed Arundo Donax along with biomass valorization. As a prerequisite for life cycle assessments, a baseline mathematical model was developed to estimate the yields of biomass to bioenergy valorization chain including the estimation of biomass yield per m3 sediment, bioenergy yields from valorization schemes, expected green electricity yield, and the phytoremediation time frame. This mathematical model was applied to develop a parametric life cycle inventory for two scenarios of sediment phytoremediation separately or integrated with biomass valorization, for LCA and further sensitivity and uncertainty analysis. Comparative LCA unveiled that the cost and environmental impacts of annual phytoremediation of 1m3 sediment alone or integrated with biomass valorization are much inferior to the corresponding sediment landfill as the inevitable alternative approach for sediment management. With the chloride bioaccumulation capacity of 9940 mg per kg dry biomass of A. donax, the phytoremediation of sediment with chloride concentration higher than 1650 mg/kg may not be achievable in a realistic time frame. Due to the importance of considering sediment depth and the effectiveness of the plant rooting system in estimating the performance of phytoremediation and the time frame, the volume of sediment (1m3) is a more appropriate functional unit than the surface area (ha) for LCA studies of phytoremediation. In addition, considering the volume of sediment as a functional unit retains comparability to other valorization scenarios such as sediment incorporation in cementitious matrices and management scenarios such as landfill, which are generally expressed on a volume or mass basis. Integrating biomass-derived bioenergy production into phytoremediation could offer local and global benefits in terms of economy and environment mainly due to carbon sequestration and avoiding fossil-based fuels.

The Role of Lignin in the Compartmentalization of Cadmium in Maize Roots Is Enhanced by Mycorrhiza.

In nature, arbuscular mycorrhizal fungi (AMF) play a crucial role in the root systems of plants. They can help enhance the resistance of host plants by improving the compartmentalization of toxic metal contaminants in the cell walls (CWs). However, the functions and responses of various CW subfractions to mycorrhizal colonization under Cd exposure remain unknown. Here we conducted a study to investigate how Cd is stored in the cell walls of maize roots colonized by Funneliformis mosseae. Our findings indicate that inoculating the roots with AMF significantly lowers the amount of Cd in the maize shoots (63.6 ± 6.54 mg kg-1 vs. 45.3 ± 2.19 mg kg-1, p < 0.05) by retaining more Cd in the mycorrhized roots (224.0 ± 17.13 mg kg-1 vs. 289.5 ± 8.75 mg kg-1, p < 0.01). This reduces the adverse effects of excessive Cd on the maize plant. Additional research on the subcellular distribution of Cd showed that AMF colonization significantly improves the compartmentalization of 88.2% of Cd in the cell walls of maize roots, compared to the 80.8% of Cd associated with cell walls in the non-mycorrhizal controls. We observed that the presence of AMF did not increase the amount of Cd in pectin, a primary binding site for cell walls; however, it significantly enhanced the content of lignin and the proportion of Cd in the total root cell walls. This finding is consistent with the increased activity of lignin-related enzymes, such as PAL, 4CL, and laccase, which were also positively impacted by mycorrhizal colonization. Fourier transform infrared spectroscopy (FTIR) results revealed that AMF increased the number and types of functional groups, including -OH/-NH and carboxylate, which chelate Cd in the lignin. Our research shows that AMF can improve the ability of maize plants to tolerate Cd by reducing the amount of Cd transferred from the roots to the shoots. This is achieved by increasing the amount of lignin in the cell walls, which binds with Cd and prevents it from moving through the plant. This is accomplished by activating enzymes related to lignin synthesis and increasing the exposure of Cd-binding functional groups of lignin. However, more direct evidence on the immobilization of Cd in the mycorrhiza-altered cell wall subfractions is needed.

Arabidopsis thaliana RPL13aC affects root system architecture through shoot potassium accumulation.

Plant root system architecture shows complex patterns adapting to different nutritional conditions. In Arabidopsis thaliana, root slanting is a behaviour that is observed when plants are grown on a solid agar plate vertically. However, the regulatory mechanisms of root slanting in response to nutrient conditions are not fully understood. In this study, we found that mutants of A. thaliana ribosome protein RPL13aC, which is expressed in root tips and leaves, exhibit a decreased root-slanting phenotype. Ionomic analysis revealed that rpl13ac mutants have a reduced K content in shoots but not in roots. Because K+ availability has been suggested to affect root coiling, we hypothesized that the decreased root slanting of rpl13ac mutants is caused by the decrease in K content in their shoots. Decapitating shoots or limiting K supply dramatically decreased root slanting in wild-type (WT) plants. We found that the expression of HIGH-AFFINITY K+ TRANSPORTER 5 (HAK5) significantly decreased in the roots of rpl13ac mutants. Mutants of hak5 showed decreased shoot K contents and decreased root slanting, supporting that the decreased shoot K+ accumulation results in less root slanting. K+ replenishment to the shoots of rpl13ac, hak5 mutants and K-starved WT plants recovered their root slanting significantly. These results indicate that plants adjust root slanting in response to K+ accumulation in shoots. Further analysis showed that rpl13ac mutants have abnormal thigmotropic responses, which may be responsible for their defects in root slanting. Altogether, these results revealed K+ -dependent mechanisms that affect root system architecture.

Metabolic profile and physiological mechanisms underlying the promoting effects of TiO2NPs on the photosynthesis and growth of tomato

Titanium dioxide nanoparticles (TiO2NPs) are photocatalysts that can boost crop photosynthesis. However, the effects of TiO2NPs on photosynthesis performance in tomato plants as well as the underlying mechanisms are unknown. In this research, the effects of synthesized TiO2NPs on growth, photosynthetic performance and the mechanism underlying enhanced photosynthesis performance were assessed in tomato plants. The results showed that the positive effect of TiO2NPs on growth is concentration-dependent, with 0.5 g L−1 of TiO2NPs stimulated the maximum growth in tomato plants. However, TiO2NPs negatively influenced the growth of tomato plants when it was applied at ≥1 g L−1. At 0.5 g L−1 of TiO2NPs, agronomic traits such as plant height, stem diameter and root system were significantly promoted in the treated plants compared to the other concentrations. In addition, the photosynthetic performance of tomato plants was significantly promoted when they were treated with 0.5 g L−1 of TiO2NPs. Further investigation revealed that TiO2NPs significantly increased the net photosynthetic efficiency, the activity of Rubisco and chloroplast F1F0-ATP synthase, and the content of NADPH in the chloroplast. The results also showed that this photocatalyst positively improved stomatal conductance, transpiration rate, and water use efficiency in the treated plants when applied at 0.5 g L−1. In addition, TiO2NPs significantly increased the electron transport rate, actual quantum yield, and photochemical quenching coefficient, while it reduced the non-photochemical quenching parameter and non-photochemical quenching coefficient when applied at 0.5 g L−1. Taken together, the results of this study revealed that TiO2NPs can improve the growth of tomato plants by enhancing photosynthesis rate and improving photosynthetic parameters.

Root traits correlated with soybean yield in a subtropical region

Root system plays a crucial role in plants’ anchoring, water and nutrients acquisition and storage of carbohydrates. While it is understood that root system traits contribute to crop yield, little is known about the particular effects of root morphology over crop yield, even on major crops such as soybean (Glycine max). The objective of this study was to investigate if distinct soybean grain yield plants, grown at different sites, displayed differences in their root system morphology. This distinct traits in the root system should be responsible to the differences of yield, thus, showing which traits should be followed in breeding programs to develop higher yield cultivars. The soybean cultivar DM 5958 RSF IPRO was sowing in a randomized complete block design experiment. Treatments comprised three cultivation sites and five soybean grain yield classes. Plant emergence and root system morphology attributes were evaluated. Results showed that late emergence negatively influenced root development. A huge difference among sites over very thin (89%) and thin (85%) roots was found in the high yield class, and since the plants have similar yield, it appeared that the thin and very thin roots length have no impact on the yield, being influenced mostly by the environment. Forks and tips roots didn’t show a pattern. In contrast, roots volume only showed a 22% reduction, demonstrating to be less influenced by the environment, resulting in a greater correlation with the grain yield. Thus identified as the main attribute to be explored when seeking to select new soybean cultivars.

Plasticity of root hair and rhizosheath traits and their relationship to phosphorus uptake in sorghum.

Sorghum is an essential crop for resilient and adaptive responses to climate change. The root systems of crop plants significantly contribute to the tolerance of abiotic stresses. There is little information on sorghum genotypes' root systems and plasticity to external P supply. In this paper, we investigated the variations in root systems, as well as the responses, trait relationships, and plasticity of two sorghum genotypes (Naga Red and Naga White), popularly grown in Ghana, to five external P concentrations ([P]ext): 0, 100, 200, 300, and 400 mg P kg-1 soil. Sorghum plants were grown in greenhouse pots and harvested for root trait measurements at the five-leaf and growing point differentiation (GPD) developmental stages. The plants were responsive to [P]ext and formed rhizosheaths. The two genotypes showed similar characteristics for most of the traits measured but differed significantly in total and lateral root lengths in favor of the red genotype. For example, at the five-leaf growth stage, the lateral root length of the red and white genotypes was 22.8 and 16.2cm, respectively, but 124 and 88.9cm, at the GPD stage. The responses and plasticity of the root system traits, including rhizosheath, to [P]ext were more prominent, positive, and linear at the five-leaf stage than at the GPD growth stage. At the five-leaf growth stage, total root length increased by about 2.5-fold with increasing [P]ext compared to the unamended soil. At the GPD stage, however, total root length decreased by about 1.83-fold as [P]ext increased compared to the unamended soil. Specific rhizosheath weight correlated with RHD, albeit weakly, and together explained up to 59% of the variation in tissue P. Root hair density was more responsive to P supply than root hair length and showed a similar total and lateral root length pattern. Most desirable responses to P occurred at a rate of 200-300 mg P kg-1 soil. It is concluded that sorghum would form rhizosheath, and [P]ext could be critical for the early vigorous growth of sorghum's responsive root and shoot traits. Beyond the early days of development, additional P application might be necessary to sustain the responses and plasticity observed during the early growth period, but this requires further investigation, potentially under field conditions.

Effect of Trichoderma viride on insoluble phosphorus absorption ability and growth of Melilotus officinalis

Phosphorus (Pi) deficiency is a major factor of limiting plant growth. Using Phosphate-solubilizing microorganism (PSM) in synergy with plant root system which supply soluble Pi to plants is an environmentally friendly and efficient way to utilize Pi. Trichoderma viride (T. viride) is a biocontrol agent which able to solubilize soil nutrients, but little is known about its Pi solubilizing properties. The study used T. viride to inoculate Melilotus officinalis (M. officinalis) under different Pi levels and in order to investigate the effect on Pi absorption and growth of seedlings. The results found that T. viride could not only solubilizate insoluble inorganic Pi but also mineralize insoluble organic Pi. In addition, the ability of mineralization to insoluble organic Pi is more stronger. Under different Pi levels, inoculation of T. viride showed that promoted the growth of aboveground parts of seedlings and regulated the morphology of roots, thus increasing the dry weight of seedlings. The effect of T. viride on seedling growth was also reflected the increasing of chlorophyll fluorescence parameters and photosynthetic pigment content. Moreover, compared to the uninoculated treatments, inoculation of T. viride also enhanced Pi content in seedlings. Thus, the T. viride was a beneficial fungus for synergistic the plant Pi uptake and growth.

Genetic Interaction between Arabidopsis SUR2/CYP83B1 andGNOM Indicates the Importance ofStabilizing Local Auxin Accumulation inLateral Root Initiation.

Lateral root (LR) formation is an important developmental event for the establishment of the root system in most vascular plants. In Arabidopsis thaliana, the fewer roots (fwr) mutation in the GNOM gene, encoding a guanine nucleotide exchange factor of ADP ribosylation factor that regulates vesicle trafficking, severely inhibits LR formation. Local accumulation of auxin response for LR initiation is severely affected in fwr. To better understand how local accumulation of auxin response for LR initiation is regulated, we identified a mutation, fewer roots suppressor1 (fsp1), that partially restores LR formation in fwr. The gene responsible for fsp1 was identified as SUPERROOT2 (SUR2), encoding CYP83B1 that positions at the metabolic branch point in the biosynthesis of auxin/indole-3-acetic acid (IAA) and indole glucosinolate. The fsp1 mutation increases both endogenous IAA levels and the number of the sites where auxin response locally accumulates prior to LR formation in fwr. SUR2 is expressed in the pericycle of the differentiation zone and in the apical meristem in roots. Time-lapse imaging of the auxin response revealed that local accumulation of auxin response is more stable in fsp1. These results suggest that SUR2/CYP83B1 affects LR founder cell formation at the xylem pole pericycle cells where auxin accumulates. Analysis of the genetic interaction between SUR2 and GNOM indicates the importance of stabilization of local auxin accumulation sites for LR initiation.