Root Physiology Research Articles

Comparative Outcomes of LSTR 3-Mix MP Therapy in Treating Chronic and Necrotic Pulp Conditions in Deciduous Molars

Background: LSTR 3-Mix MP therapy is a non-instrumentation endodontic treatment designed for managing pulpally involved deciduous teeth. It offers a minimally invasive alternative to conventional pulpectomy, particularly in cases with anatomical complexities and physiologic root resorption. This study evaluates the clinical and radiological outcomes of LSTR 3-Mix MP therapy in treating chronic and necrotic pulp conditions in deciduous molars. Methods: This prospective clinical study was performed from November 2023 to October 2024 evaluated 60 deciduous molars in children aged 3–8 years, divided into Group A (vital pulp with chronic pulpitis) and Group B (non-vital pulp with/without periradicular lesions), conducted at Bangladesh Shishu Hospital & Institute and Shah Ali Dental Clinic, Dhaka. Results: Clinical success was achieved in 96.7% of cases in both groups, with complete resolution of symptoms, including pain, tenderness, swelling, and abscesses. Radiological success in Group A (vital teeth) reached 100%, with no pathological lesions observed. In Group B (non-vital teeth), periradicular radiolucency resolved in 73.3% of cases, decreased in 13.3%, and remained unchanged in 13.3%. Group A exhibited no swelling pre- or posttreatment, while in Group B, swelling resolved entirely by the second follow-up, with significant improvement noted earlier (p = 0.001, p = 0.042). Conclusion: LSTR 3-Mix MP therapy is a highly effective, minimally invasive treatment for deciduous molars with chronic and necrotic pulp conditions. It demonstrated excellent clinical and radiological outcomes, supporting its use as a promising alternative to conventional pulpectomy in pediatric patients.

Overexpression of the tomato pathogenesis-related gene SlPR-1.9 confers increased tolerance to salt stress in Arabidopsis thaliana

Pathogenesis-related (PR) proteins are essential components of plant defense mechanisms, responding to both biotic and abiotic stresses. Among these, PR-1 proteins feature a CAP (Cysteine-rich secretory proteins, Antigen 5, and Pathogenesis-related 1) domain, which is crucial for immune responses and pathogen defense due to its ability to stabilize protein structures and interact with various molecules. This study investigated the role of the tomato PR-1 gene SlPR-1.9 in enhancing salt tolerance in Arabidopsis thaliana. The gene’s coding sequence was cloned and transferred into Arabidopsis to create SlPR-1.9 overexpression lines. These transgenic lines, alongside wild-type plants, were exposed to salt stress (150 mM NaCl) to assess their tolerance. Morphological analysis revealed that the transgenic lines demonstrated greater resilience to salt stress compared to wild-type plants, with less severe leaf curling and color changes. Additionally, lower proline accumulation, a stress marker, in the transgenic lines indicated an enhanced adaptive response. Bioinformatics analysis of the protein encoded by SlPR-1.9, A0A3Q7HSC4, suggested a strong interaction with galactolipase. Expression analysis showed that SlPR-1.9 was mainly expressed in roots and during early fruit development, suggesting a significant role in root physiology and stress response. These findings indicate that overexpression of SlPR-1.9 can improve plant tolerance to salt stress, offering potential applications for enhancing crop resilience to environmental challenges.

Root physiological and morphology processes co-regulate the growth of Chinese-fir saplings in response to warming and precipitation reduction in the sub-tropical regions

Subtropical China is projected to experience elevated temperature greater than the mean global temperature increase and is accompanied by reduced precipitation. The plasticity of roots to changing environment strongly influences ecosystem feedbacks to climate change. However, knowledge gaps on the individual and combined effects of warming and precipitation reduction on root systems hinder our ability to accurately predict the growth and adaptability of forests under future climate change. To examine the effects of warming (W) and precipitation reduction (P) on roots physiology and morphology of Chinese-fir saplings, we used a randomized complete block design with factorial soil warming (ambient, ambient + 5℃) and precipitation reduction (ambient, ambient-50 %) treatments. A full excavation method was adopted to obtain roots, then we measured the root physiology (osmoregulatory substances, oxidant substances, protective enzymes, endogenous hormones), morphology (specific root length, SRL; surface root area, SRA; root tissue density, RTD). The content of carbon and nitrogen, isotopes (δ13C and δ15N); soil temperature, soil moisture and sapling growth were also measured. We found that compared with the control, W decreased the abscisic acid (IAA) content; P increased the contents of hydrogen peroxide (H2O2) and proline (Pro), and decreased the contents of IAA and cytokinin (CTK); warming plus precipitation reduction (WP) increased the Pro content, and decreased the contents of IAA and CTK. In addition, the effects of W and P on root morphology varied with soil depth and root diameter class. W, P, and WP all increased fine root SRL and SRA in deep soil. Warming and precipitation reduction could affect physiological traits (e.g. non-enzymatic substances and antioxidant enzymes) and subsequently morphological traits via influencing soil environment and root tissue chemistry. Collectively, the results indicated that Chinese-fir saplings responded to warming and precipitation reduction by comprehensive regulation of the non-enzymatic substances (e.g., osmotic substances and endogenous hormones) of fine roots and changing root morphological characteristics in deep soil.

Comparative Evaluation of the Accuracy of Electronic Apex Locator and Digital Radiography for Working Length Determination in Primary Teeth: A Systematic Review.

It is challenging to perform a pulpectomy procedure in primary tooth because of its physiological root resorption and variation in root morphology. Working length measurement is considered to be one of the critical steps, as it determines the extent of obturation and apical seal. To compare the accuracy of electronic apex locator (EAL) and digital radiography (DR) for working length determination in primary teeth. In this systematic review, electronic databases and grey literature were searched from 1st January 2005 to 1st January 2023 for randomized control trial, non- randomized control trial, in vitro studies, ex vivo studies that compared accuracy of EAL and DR in primary teeth. Two reviewers independently identified studies, retrieved data, and assessed risk of bias using the revised and validated MINORS (methodological index for non-randomized studies) criteria. Ten studies were included in qualitative analysis. Seven out of ten studies showed low risk of bias whereas other three studies showed high risk of bias. In view of methodological heterogeneity of the findings, a meta-analysis was not conducted. Available evidence suggests a moderate quality of evidence in this systematic review. Analyzing the ten studies included in this systematic review, the majority of studies showed statistically insignificant difference between EAL and DR. However, EAL was closer to actual WL as compared to DR. Based on the evidence that is currently available; EAL can be considered as an alternative for working length measurement in primary teeth.

Effect of α7 nAChR-autophagy axis of deciduous tooth pulp stem cells in regulating IL-1β in the process of physiological root resorption of deciduous teeth.

Physiological root resorption of deciduous teeth is a normal phenomenon occurring during the developmental stages of children. Previous research has indicated the pivotal role of the inflammatory microenvironment in this process, although the specific mechanisms remain unclear. This study is aimed at elucidating the involvement of the alpha7 nicotinic acetylcholine receptors (α7 nAChR)-autophagy axis in the regulation of the inflammatory microenvironment during physiological root resorption in deciduous teeth. Samples were collected from deciduous teeth at various stages of physiological root resorption, and deciduous dental pulp stem cells (DDPSCs) were isolated and cultured during the mid-phase of root resorption. The findings revealed a substantial infiltration of the pulp of deciduous teeth at the mid-phase of root resorption, characterized by elevated expression levels of α7 nAChR and IL-1β. Significantly increased IL-1β and α7 nAChR expressions were observed in DDPSCs during the mid-phase of root resorption, with α7 nAChR demonstrating a regulatory effect on IL-1β. Moreover, evidence suggested that mechanical stress may act as a trigger, regulating autophagy and IL-1 expression via α7 nAChR. In conclusion, mechanical stress was identified as a regulator of autophagy in DDPSCs through α7 nAChR, influencing the expression of IL-1β and contributing to the formation of the inflammatory microenvironment. This mechanism plays a crucial role in the physiological root resorption of deciduous teeth. KEY MESSAGES: The pulp of deciduous teeth at mid-phase of root resorption was heavily infiltrated with high expression of α7nAChR and IL-1β. α7 nAChR acts as an initiating factor to regulate IL-1β through autophagy in DDPSCs. Mechanical stress can regulate autophagy of DDPSCs through α7 nAChR and thus affect IL-1β expression and inflammatory microenvironment formation in physiological root resorption in deciduous teeth.

Postponed Application of Phosphorus and Potassium Fertilizers Mitigates the Damage of Late Spring Coldness by Improving Winter Wheat Root Physiology.

Late spring coldness (LSC) is the main limiting factor threatening wheat yield and quality stability. Optimal nutrient management is beneficial in mitigating the harms of LSC by improving wheat root physiology. This study proposed a nutrient management strategy that postponed the application of phosphorus (P) and potassium (K), effectively strengthening wheat's defense against LSC. This experiment used the winter cultivar "Yannong19" (YN 19) as plant material for two consecutive years (2021-2022 and 2022-2023). Two fertilizer treatments were used: traditional P and K fertilizers application (R1: base fertilizer: jointing fertilizer = 10:0) and postponed P and K fertilizers application (R2: base fertilizer: jointing fertilizer = 5:5); wheat plants at the anther connective formation stage shifted to temperature-controlled phytotrons for normal (T0, 11 °C/4 h) and low temperatures (T1, 4 °C/4 h; T2, -4 °C/4 h) as treatments of LSC. The results showed that under low temperature (LT) treatment, compared with R1, the R2 treatment increased the concentrations of osmotic adjustment substances (soluble sugars and soluble protein contents by 6.2-8.7% and 3.0-8.9%), enhanced activities of antioxidant enzymes (superoxide dismutase, peroxidase and catalase activities by 2.2-9.1%, 6.2-9.7% and 4.2-8.4%), balanced the hormone concentrations (increased IAA and GA3 contents by 2.8-17.5% and 10.4-14.1% and decreased ABA contents by 7.2-14.3%), and reduced the toxicity (malondialdehyde, hydrogen peroxide content and O2·- production rate by 5.7-12.4%, 17.7-22.8% and 19.1-19.1%) of the cellular membranes. Furthermore, the wheat root physiology in R2 significantly improved as the root surface area and dry weight increased by 5.0-6.6% and 4.7-6.6%, and P and K accumulation increased by 7.4-11.3% and 12.2-15.4% compared to R1, respectively. Overall, the postponed application of P and K fertilizers enhanced the physiological function of the root system, maintained root morphology, and promoted the accumulation of wheat nutrients under the stress of LSC.

The effect of constitutive root isoprene emission on root phenotype and physiology under control and salt stress conditions.

Isoprene, a volatile hydrocarbon, is typically emitted from the leaves of many plant species. Given its well-known function in plant growth and defense aboveground, we examined its effects on root physiology. We used isoprene-emitting (IE) lines and a non-emitting (NE) line of Arabidopsis and investigated their performance by analyzing root phenotype, hormone levels, transcriptome, and metabolite profiles under both normal and salt stress conditions. We show that IE lines emitted tiny amounts of isoprene from roots and showed an increased root/shoot ratio compared with NE line. Isoprene emission exerted a noteworthy influence on hormone profiles related to plant growth and stress response, promoting root development and salt-stress resistance. Methyl erythritol 4-phosphate pathway metabolites, precursors of isoprene and hormones, were higher in the roots of IE lines than in the NE line. Transcriptome data indicated that the presence of isoprene increased the expression of key genes involved in hormone metabolism/signaling. Our findings reveal that constitutive root isoprene emission sustains root growth under saline conditions by regulating and/or priming hormone biosynthesis and signaling mechanisms and expression of key genes relevant to salt stress defense.

Comparative transcriptome analyses reveal regulatory network and hub genes of aluminum response in roots of elephant grass (Cenchrus purpureus)

Aluminum (Al) toxicity severely restricts the growth and productivity of elephant grass in acidic soils around the world. However, the molecular mechanisms of Al response have not been investigated in elephant grass. In this study, we conducted phenotype, physiology, and transcriptome analysis of elephant grass roots in response to Al stress. Phenotypic analysis revealed that a low concentration of Al stress improved root growth while higher Al concentrations inhibit root growth. Al stress significantly increased the citrate (CA) content in roots, while the expression levels of genes related to citrate synthesis were substantially changed. The multidrug and toxic compound extrusion (MATE) family were identified as hub genes in the co-expression network of Al response in elephant grass roots. Phylogenetic analysis showed that hub genes CpMATE93 and CpMATE158 belonged to the same clade as other MATE genes reported to be involved in citrate transport. Additionally, overexpression of CpMATE93 conferred Al resistance in yeast cells. These results provide a theoretical basis for further studies of molecular mechanisms in the elephant grass response to Al stress and could help breeders develop elite cultivars with Al tolerance.

External aortic annuloplasty with a dedicated expansible ring improves outcomes in remodeling root repair compared with homemade Dacron ring

ObjectivesIn remodeling valve-sparing root replacement with external annuloplasty, we compare long-term outcomes of a calibrated expansible extra-aortic ring with a homemade Dacron ring. MethodsAll patients (2003-2020) operated for root aneurysm with/without aortic insufficiency (AI) were included. The standardized CAVIAAR (conservation aortique valvulaire dans les insuffisances aortiques et anévrysmes de la racine-Valve sparing in aortic insufficiencies and root aneurysms) technique was root remodeling and external annuloplasty ring with the EXTRA-AORTIC Ring or homemade Dacron ring. ResultsAmong 486 patients (age 52.3 ± 14.0 years) operated for root aneurysm, 375 (repair rate: 77.1%) underwent root remodeling with annuloplasty (extra-aortic ring, n = 289, vs Dacron ring, n = 86). At 10 years (median follow-up, 4.08 years’ interquartile range, 1.95-7.61), unmatched and matched analysis showed that patients with extra-aortic ring had greater survival, similar to the general population (93.3% vs 79.9%, P = .097), lower reoperation incidence (2.0% vs 9.7%, P = .0098), and lower AI grade >2 recurrence (1.9% vs 11.2%, P = .0042), compared with patients with a Dacron ring. Mixed-effect model showed that with extra-aortic ring annuloplasty, annular dilation over time (P = .0033) was prevented and, compared with the homemade Dacron ring, root expansibility was better preserved (3.22% vs 2.12%, P = .002) and mean transvalvular gradient was lower (6.58 mm Hg vs 7.94 mm Hg, P = .001). Tricuspid and bicuspid valves with extra-aortic ring had similar reoperation (4.3% vs 0.85%, P = .65) and AI grade >2 incidence (2.7% vs 1.2%, P = .61), expansibility (P = .29), and diameter (P = .47), whereas mean transvalvular gradient was lower for tricuspid valves (5.58 mm Hg vs 7.60 mm Hg, P = .004). ConclusionsValve-sparing root remodeling with calibrated expansible extra-aortic ring annuloplasty improves the outcomes of reoperation and recurrent AI compared with a homemade Dacron ring. It prevents dilation and maintains physiological root dynamics for durable valve repair.

Methods for Measuring Nutrient Uptake in Maize Using Nitrogen Stable Isotopes.

Nitrogen is a key nutrient for plant growth and development, and understanding nutrient uptake is central to improving nitrogen use efficiency in crops, including maize. Reducing the need for fertilizer without reducing yield is extremely important, as nitrogen fertilizers come with a high environmental cost, in terms of both emissions from manufacturing and losses to waterways or volatilization off fields. Maize develops multiple different root types, including primary, seminal, crown, and brace roots. Part of improving efficiency in maize involves understanding the differences in nutrient uptake via each distinct root type, but these differences have been largely ignored to date. Here, we describe a protocol that uses stable isotopes for determining nitrogen uptake rates by maize root types. We describe the steps both for intact roots, for which we use rhizoboxes with openable front windows that allow access to the roots without disturbing the rest of the plant, and for field-grown plants, for which intact analysis is not feasible and requires excising the roots. The methods described here can also be modified to measure uptake kinetics and for monitoring nutrient translocation between roots and shoots. Advancing our understanding of root physiology and nutrient dynamics will improve breeding opportunities for efficient nutrient uptake varieties, reducing the need for fertilizer additions.

Enhancing root physiology for increased yield in water-saving and drought-resistance rice with optimal irrigation and nitrogen.

Water-saving and drought-resistance rice (WDR) plays a vital role in the sustainable development of agriculture. Nevertheless, the impacts and processes of water and nitrogen on grain yield in WDR remain unclear. In this study, Hanyou 73 (WDR) and Hyou 518 (rice) were used as materials. Three kinds of nitrogen fertilizer application rate (NFAR) were set in the pot experiment, including no NFAR (nitrogen as urea applied at 0 g/pot), medium NFAR (nitrogen as urea applied at 15.6 g/pot), and high NFAR (nitrogen as urea applied at 31.2 g/pot). Two irrigation regimes, continuous flooding cultivation and water stress, were set under each NFAR. The relationships between root and shoot morphophysiology and grain yield in WDR were explored. The results demonstrated the following: 1) under the same irrigation regime, the grain yield of two varieties increased with the increase of NFAR. Under the same NFAR, the reduction of irrigation amount significantly reduced the grain yield in Hyou 518 (7.1%-15.1%) but had no substantial influence on the grain yield in Hanyou 73. 2) Under the same irrigation regime, increasing the NFAR could improve the root morphophysiology (root dry weight, root oxidation activity, root bleeding rate, root total absorbing surface area, root active absorbing surface area, and zeatin + zeatin riboside contents in roots) and aboveground physiological indexes (leaf photosynthetic rate, non-structural carbohydrate accumulation in stems, and nitrate reductase activity in leaves) in two varieties. Under the same NFAR, increasing the irrigation amount could significantly increase the above indexes in Hyou 518 (except root dry weight) but has little effect on Hanyou 73. 3) Analysis of correlations revealed that the grain yield of Hyou 518 and Hanyou 73 was basically positively correlated with aboveground physiology and root morphophysiology, respectively. The grain yield could be maintained by water stress under medium NFAR in WDR. The improvement of root morphophysiology is a major factor for high yield under the irrigation regime and NFAR treatments in WDR.

Fungi diversity in roots of Guarianthe skinneri in urban condition: velamen versus cortex

Objective: To Identify the endophytic fungal community of the G. skinneri root in urban populations, showing differences in composition between velamen and cortex to better understand the fungus-root interaction in these orchids.
 Design/Methodology/Approach: We collected tissues from velamen and root from five specimens of G. skinneri growing on urban trees in Tapachuala, Chiapas. We extracted DNA, PCR amplified the ITS marker, sequenced on the Illumina platform followed by diversity analyses and taxonomic assignment.
 Results: We detected 845 OTUs that were assigned to the Fungi kingdom. Velamen and cortex share 403 OTUs, 402 were found exclusively in velamen and 40 in cortex. Besides orchid mycorrhiza forming fungi, we detected other species (e.g Alternaria sp., Beauveria sp., Fusarium sp., Glomus sp. and Tricoderma sp.) that could be involved in root physiology during development and defense against pathogens and predators
 Study Limitations/Implications: Metagenomic studies provide substantial amounts of data that go beyond conventional studies. However, the information generated is still limited regarding the role of each endophyte.
 Findings/Conclusions: Despite these limitations, our work fills a knowledge gap because we detected endophytes that were previously unknown for G. skinneri, leading to new research questions about root-endophyte relationships.

Soil amendments with nanoparticles control cucumber wilt caused by Fusarium oxysporium

Management of Fusarium wilt, a destructive plant disease, mainly relies on chemicals, but research on novel and eco-friendly methods is needed due to the hazardous effects of chemical pesticides. This study explored the soil application of zinc oxide nanoparticles (ZnONPs) to manage Fusarium wilt disease in cucumber plants. The antifungal activity of ZnONPs against in-vitro growth of Fusarium oxysporum was tested through food poisoning test on the potato dextrose agar medium. The in-vivo potential of NPs for managing Fusarium wilt was checked in pot experiment. In-vitro results confirmed the concentration-dependent in-vitro antifungal activity. The NPs application at 500 µg/ml and 600 µg/ml concentrations showed phytotoxicity and significantly inhibited seed germination and growth of cucumber plants. However, NPs at 300 µg/ml significantly suppressed the pathogenic effects of F. oxysporum on cucumber plants without any phytotoxic effect. The pathogen-inoculated cucumber plants grown in soil amended with NPs showed significantly enhanced growth, lower disease severity, and improved root physiology compared to untreated plants. The plants under NPs treatment showed higher chlorophyll and nitrogen content while decreased membrane permeability and malondialdehyde content. Along with direct antifungal activity, the application of NPs caused an increased expression of defense-related genes and higher activities of defense-related enzymes. These findings verified the efficiency of ZnONPs for suppressing Fusarium wilt disease in cucumber crops, thereby promoting a non-chemical and environmentally friendly approach to controlling Fusarium wilt disease.

Circadian clock genes REV-ERBα regulates the secretion of IL-1β in deciduous tooth pulp stem cells by regulating autophagy in the process of physiological root resorption of deciduous teeth

Physiological root resorption is a common occurrence during the development of deciduous teeth in children. Previous research has shown that the regulation of the inflammatory microenvironment through autophagy in DDPSCs is a significant factor in this process. However, it remains unclear why there are variations in the autophagic status of DDPSCs at different stages of physiological root resorption. To address this gap in knowledge, this study examines the relationship between the circadian clock of DDPSCs, the autophagic status, and the periodicity of masticatory behavior. Samples were collected from deciduous teeth at various stages of physiological root resorption, and DDPSCs were isolated and cultured for analysis. The results indicate that the circadian rhythm of important autophagy genes, such as Beclin-1 and LC3, and the clock gene REV-ERBα in DDPSCs, disappears under mechanical stress. Additionally, the study found that REV-ERBα can regulate Beclin-1 and LC3. Evidence suggests that mechanical stress is a trigger for the regulation of autophagy via REV-ERBα. Overall, this study highlights the importance of mechanical stress in regulating autophagy of DDPSCs via REV-ERBα, which affects the formation of the inflammatory microenvironment and plays a critical role in physiological root resorption in deciduous teeth.

Suberin deficiency and its effect on the transport physiology of young poplar roots.

The precise functions of suberized apoplastic barriers in root water and nutrient transport physiology have not fully been elucidated. While lots of research has been performed with mutants of Arabidopsis, little to no data are available for mutants of agricultural crop or tree species. By employing a combined set of physiological, histochemical, analytical, and transport physiological methods as well as RNA-sequencing, this study investigated the implications of remarkable CRISPR/Cas9-induced suberization defects in young roots of the economically important gray poplar. While barely affecting overall plant development, contrary to literature-based expectations significant root suberin reductions of up to 80-95% in four independent mutants were shown to not evidently affect the root hydraulic conductivity during non-stress conditions. In addition, subliminal iron deficiency symptoms and increased translocation of a photosynthesis inhibitor as well as NaCl highlight the involvement of suberin in nutrient transport physiology. The multifaceted nature of the root hydraulic conductivity does not allow drawing simplified conclusions such as that the suberin amount must always be correlated with the water transport properties of roots. However, the decreased masking of plasma membrane surface area could facilitate the uptake but also leakage of beneficial and harmful solutes.

Observing root growth and signalling responses to stress gradients and pathogens using the bi-directional dual-flow RootChip.

Plants respond to environmental stressors with adaptive changes in growth and development. Central to these responses is the role of calcium (Ca2+) as a key secondary messenger. Here, the bi-directional dual-flow RootChip (bi-dfRC) microfluidic platform was used to study defence signalling and root growth. By introducing salinity as sodium chloride (NaCl) treatment via a multiplexed media delivery system (MMDS), dynamic gradients were created, mimicking natural environmental fluctuations. Signal analysis in Arabidopsis thaliana plants showed that the Ca2+ burst indicated by the G-CaMP3 was concentration dependent. A Ca2+ burst initiated in response to salinity increase, specifically within the stele tissue, for 30 seconds. The signal then intensified in epidermal cells directly in contact with the stressor, spreading directionally towards the root tip, over 5 minutes. Inhibition of propidium iodide (PI) stain transport through the xylem was observed following salinity increase, contrasting with flow observed under control conditions. The interaction of Phytophthora capsici zoospores with A. thaliana roots was also studied. An immediate directional Ca2+ signal was observed during early pathogen recognition, while a gradual, non-directional increase was observed in Orp1_roGFP fluorescent H2O2 levels, over 30 min. By adjusting the dimensions of the bi-dfRC, plants with varying root architectures were subjected to growth analysis. Growth reduction was observed in A. thaliana and Nicotiana benthamiana roots when exposed to salinity induced by 100 mM NaCl, while Solanum lycopersicum exhibited growth increase over 90 minutes at the same NaCl concentration. Furthermore, novel insights into force sensing in roots were gained through the engineering of displaceable pillars into the bi-dfRC channel. These findings highlight the vital role of controlling fluid flow in microfluidic channels in advancing our understanding of root physiology under stress conditions.

Analysis of exogenous lactic acid bacteria on growth and development of different herbaceous peony varieties and rhizosphere soil nutrients

There are replanting problems in the production of herbaceous peony. If ramet seedlings are replanted in the original planting hole, they weaken year-by-year until their death, which reduces the land utilisation rate and increases the production costs. In this study, exogenous lactic acid bacteria (LAB, the main component is Lactobacillus plantarum) were applied to improve the planting soil of herbaceous peony for the first time to alleviate the replanting problems, to reduce the production costs, and to provide a new way to promote the of the herbaceous peony industry. In this study, herbaceous peony main cultivars varieties ‘Dafugui’ ‘Hongxiuqiu’ and ‘Zifengyu’ were selected, and experiments were conducted using exogenous LAB. Morphological, rhizosphere soil, and root physiology indexes were measured by sampling at the end of the high-growth periods of herbaceous peony. The results showed that after LAB treatment, the plant height, flowering rate, other morphological indexes and root vitality of ‘Hongxiuqiu’ were increased, with a better promoting effect than that of ‘Dafugui’ and ‘Zifengyu’. The ‘Dafugui’ rhizosphere soil nutrient content and enzyme activity were improved, followed by ‘Hongxiuqiu’ and ‘Zifengyu’. The rhizosphere soil free salicylic acid content and root abscisic acid content decreased, whereas the soil bacterial abundance, root antioxidant enzyme activity, proline and paeoniflorin content increased in all varieties. This study found that LAB application can improve soil fertility and enzyme activity, promote the growth and development of herbaceous peony, increase the flowering rate and improve the ornamental value. However, the influence of LAB on different herbaceous peony varieties varied. Therefore, it is necessary to further expand the number of varieties, optimise the application concentration and frequency of LAB application, alleviate the replanting problems in herbaceous peony production, improve the utilisation rate of land, promote excellent varieties of herbaceous peony, and provide a new methods and references.Graphical abstract

Twice-Split Phosphorus Application Alleviates Low Temperature Stress by Improving Root Physiology and Phosphorus Accumulation, Translocation, and Partitioning in Wheat

In the context of global warming, low temperature (LT) disasters in major crops are also becoming more common. LT stress in the Huang-Huai-Hai Plain, the central wheat region in China, caused a massive reduction in wheat yields. A step towards ensuring wheat yield stability and food security, this study investigated the effects of optimizing phosphorus application on the root physiology, dry matter phosphorus accumulation, translocation, and partitioning of wheat under LT stress, using the representative cultivar Yannong 19 as the test material. The treatments included conventional phosphorus application (R1) and twice-split phosphorus application (R2), followed by −4 °C LT treatment and normal temperature (NT) treatment during the anther interval stage. Analysis of the root physiology (enzymatic activities and acid phosphatase, contents of malondialdehyde, soluble sugar, and soluble protein), phosphorus and dry matter accumulation, translocation, partitioning, and agronomic and yield-related components was carried during this research study. The results showed that the wheat root activity was significantly reduced and the antioxidant enzyme activities were increased to mitigate the damage of LT stress. Moreover, LT treatments damaged root function. The root activity and antioxidant properties were significantly lower than those of the NT treatment at the flowering stage. The dry matter and phosphorus accumulations were reduced by 30.6~33.6% and 15.1~21.3% at the flowering and maturity stages, resulting in final yield losses of 10.3~13.0%. In contrast, root activity increased by 16.1~27.2% in the twice-split phosphorus application treatments, and the root antioxidant characteristics were higher. As a result, dry matter and phosphorus accumulation increased after twice-split phosphorus application and their translocation to the grains was more; the final yield increased by 5.5~7.3%. Overall, the twice-split phosphorus application enhanced the physiological function of the root system and promoted the accumulation of nutrients and their transport to the grain, and alleviated the yield loss of wheat caused by LT stress.

Effects of Truffle Inoculation on Root Physiology and Mycorrhizosphere Microbial Communities of Carya illinoinensis Seedlings

Although they are a valuable edible ectomycorrhizal fungus, truffles (Tuber spp.) nevertheless face significant difficulties in the development of their scale. As a type of high economic value nut-like economic forest tree, the pecan (Carya illinoinensis) serves as a natural host for truffles. However, the technology for mycorrhizal synthesis in pecan has not yet been developed, and it is still unclear how certain microbes affect this process. In this study, we inoculated the pecan root system with a suspension of truffle spores and investigated the growth physiology of pecan seedlings with various infestation levels, as well as changes in the soil’s physicochemical properties and the makeup of the microbial community at the root level. The findings showed that tuber inoculation significantly increased the peroxidase activity of the pecan root system, significantly decreased the pH, and effective phosphorus content of mycorrhizosphere soil, while increasing the nitrate nitrogen content, and significantly increased the abundance and diversity of the mycorrhizosphere soil fungal community. Different groups of fungal and bacterial markers were formed in the mycorrhizosphere of pecan seedlings at different levels of infestation. In the highly infested group, Rozellomycota and lasiosphaeriaceae were the difference marker fungi, and Xanthobacteraceae, Rhizobiaceae as well as Streptococcaceae were the difference marker bacteria. In the low-infestation group, sphaerosporella was differential marker fungi, and Bacillus and Tumebacillus were differential marker bacteria. The fungal marker flora of the control group consisted of Chaetomium and Gilmaniella. Pseudomonas was the marker bacterial community. Additionally, these fungi included Collarina and Rozellomycota, and several bacteria from the genera Pseudomonas, Gemmatimonas, and others showed highly significant relationships with changes in soil pH, effective phosphorus, and nitrate nitrogen. In conclusion, pecan–truffle mycorrhizal seedlings have the potential to create the ideal microbial community structure needed for mycorrhizal growth, and these microorganisms have the potential to significantly alter the pH, effective phosphorus content, and nitrate nitrogen concentration of the mycorrhizosphere soil. Our results contribute to the understanding of how the mycorrhizosphere microbial community evolves when exogenous mycorrhizal fungi infest host plants and can offer some theoretical guidelines for growing pecan–truffle mycorrhizal seedlings.

Potential Mechanism of Optimal Tillage Layer Structure for Improving Maize Yield and Enhancing Root Growth in Northeast China

A field experiment was conducted to evaluate the effect of different tillage structures on soil physical properties, soil chemical properties, maize root morphological and physiological characteristics, and yield. Four tillage structures were designed. Soil tillage plays a prominent role in agricultural sustainability. The different tillage layer structures affected soil physical properties. An enhancement in the optimal tillage layer structure improved soil structure. The MJ tillage layer structure created an improved soil structure by regulating the soil physical properties so that the soil compaction and soil bulk density would be beneficial for crop growth, increase soil water content, and adjust the soil phrase R value and GSSI. Soil nutrients are significantly affected by soil depth, with the exception of available potassium. However, soil nutrients are influenced by different tillage layer structures with soil depth. Soil nutrient responses with depth are different for MJ layer treatment compared with other tillage layer structures. Soil organic matter (SOM) is affected with an increase in depth and is significantly influenced by different tillage layer structures, except at 20–30 cm soil depth. MJ treatment increased by 10–20% compared with other tillage layer structures. In addition, QS treatment enhanced the increased pH value in soil profile compared to others. The root morphology characteristics, including root length, root ProjArea, root SurfArea, root AvgDiam, and root volume, were affected by years, depth, and the tillage layer structures. The MJ tillage layer structure enhanced root growth by improving tillage soil structure and increasing soil air and water compared with other tillage layer treatments. Specifically, the MJ layer structure significantly increased root length and root volume via deep tillage. However, the differences in root physiological properties were not significant among treatments. The root dry weight decreased with an increase in soil depth. Most of the roots were mainly distributed in a 0–40 cm soil layer. The MJ treatment enhanced the increase in root dry weight compared with others by breaking the tillage pan layer. Among the different tillage layer structures, the difference in root dry weight was smaller with an increase in soil depth. Moreover, the MJ treatment significantly improved maize yield compared with others. The yield was increased by 14.2% compared to others under MJ treatment via improvements in the soil environment. In addition, the correlation relationship was different among yield and root morphology traits, root physiology traits, soil nutrients, and soil physical traits. So, our results showed that the MJ tillage layer structure is the best tillage structure for increasing maize yield by enhancing soil nutrients, improving the soil environment and root qualities.