Root Diameter Research Articles

Study on the Morphology and Mechanical Properties of Cynodon dactylon in the Riparian Zone Slopes of a Large Reservoir

The stability of riverbank slopes is crucial in watershed ecology. The morphology and tensile strength properties of plant roots play a significant role in slope stability, which is of great importance for the ecological stability of riverbanks. The Jinsha and Yalong River basins are the largest hydropower bases in China and are in the ecologically fragile areas of the dry and hot river valleys, yet fewer studies are available on these basins. Further studies on the growth morphology and root mechanical properties of plant roots in the riparian zone at different elevations have not been reported. Therefore, we selected the dominant species of Cynodon dactylon root as the research subject, analyzed the root morphology, and conducted indoor single-root tensile tests to study its root structure and mechanical properties at various elevations. The results showed that the root morphology of Cynodon dactylon was positively correlated with elevation. Compared to low elevations (L and M), the root length increased by 57.3% and 21.47%, the root diameter increased by 24.85% and 13.92%, the root surface area increased by 93.5% and 67.37%, and the total root volume increased by 119.91% and 107.36%. As the elevation gradient increased, the flooding time decreased, leading to more developed plant roots for Cynodon dactylon. The Young’s modulus ranged from 148.43 to 454.18 MPa for Ertan Cynodon dactylon roots and 131.31 to 355.53 MPa for Guanyingyan Cynodon dactylon roots. The maximum tensile strength, ultimate tensile strength, ultimate elongation, and Young’s modulus of the plant root of the Cynodon dactylon showed a power function relationship with the diameter. The maximum tensile strength increased as the diameter increased, while the remaining properties decreased following a power function relationship. The maximum tensile strength, ultimate tensile strength, and Young’s modulus of Cynodon dactylon were positively correlated with elevation, while the ultimate elongation was negatively correlated with elevation. The results elucidate the influence of elevation on the root morphology and mechanical properties of dominant riparian species. This provides a theoretical basis for managing and protecting riparian slopes in ecologically fragile areas.

Mycorrhizal Symbiosis Enhances P Uptake and Indole-3-Acetic Acid Accumulation to Improve Root Morphology in Different Citrus Genotypes

Arbuscular mycorrhizal fungi (AMF) are known to enhance plant growth via stimulation of root system development. However, the extent of their effects and underlying mechanisms across different citrus genotypes remain to be fully elucidated. This study investigates the impact of Funneliformis mosseae (F. mosseae) inoculation on plant growth performance, root morphology, phosphorus (P), and indole-3-acetic acid (IAA) concentrations, as well as the expression of related synthesis and transporter genes in three citrus genotypes: red tangerine (Citrus tangerine ex. Tanaka), kumquat (Fortunella margarita L. Swingle), and fragrant citrus (Citrus junos Sieb. ex. Tanaka). Following 12 weeks of inoculation, significant improvements were observed in plant height, shoot and root biomass, total root length, average root diameter, second-order lateral root development, root hair density, and root hair length across all genotypes. Additionally, F. mosseae inoculation significantly increased root P and IAA concentrations in the three citrus genotypes. Notably, phosphatase activity was enhanced in F. margarita but reduced in C. tangerine and C. junos following inoculation. Gene expression analysis revealed a universal upregulation of the P transporter gene PT5, whereas expressions of the auxin synthesis gene YUC2, transporter gene LAX2, and phosphatase gene PAP1 were commonly downregulated. Specific to genotypes, expressions of YUC5, LAX5, PIN2, PIN3, PIN6, and expansin genes EXPA2 and EXPA4 were significantly upregulated in C. tangerine but downregulated in F. margarita and C. junos. Principal component analysis and correlation assessments highlighted a strong positive association between P concentration, P and auxin synthesis, and transporter gene expressions with most root morphology traits, except for root average diameter. Conversely, IAA content and phosphatase activities were negatively correlated with these root traits. These findings suggest that F. mosseae colonization notably enhances plant growth and root system architecture in citrus genotypes via modifications in P transport and IAA accumulation, indicating a complex interplay between mycorrhizal symbiosis and host plant physiology.

Nitrogen Addition Promotes the Accumulation of Soil Particulate Organic Carbon in a Subtropical Forest

Nitrogen (N) deposition rates of terrestrial ecosystems have gradually declined but are still high in some areas. Previous studies have reported that N addition elicits diverse impacts on soil organic carbon (SOC) pools. SOC can be divided into different functional fractions, namely, particulate organic carbon (POC) and mineral-associated organic carbon (MAOC). The responses of these fractions to N addition should be elucidated to better understand the changes in SOC pools. Here, we conducted a N addition experiment (0, 40, and 80 kg N ha−1 yr−1) in a subtropical Castanopsis fabri forest to simulate N deposition. The surface (0−10 cm) SOC fractions, aboveground litter product, fine root (diameter < 2 mm) biomass, soil exchangeable cation content, and soil enzyme activity under different N addition treatments were measured. The results showed the following: (1) N addition showed a positive effect on POC and SOC contents but did not significantly affect MAOC content; (2) POC content was negatively correlated with pH and soil enzyme activity and positively correlated with aboveground litter product, suggesting that POC accumulation was influenced by aboveground litter input and microbial decomposition; (3) a close negative relationship was observed between exchangeable Al3+ and Ca2+ or K+ contents, indicating that there is likely to be a trade-off between the mineral sorption and desorption, thus resulting in an insignificant reaction of MAOC to N addition. Overall, the accumulation of SOC under short-term N addition was found to be primarily driven by POC, and the response of different SOC functional fractions to N addition was inconsistent. By incorporating these nuances into ecosystem models, it is possible to predict SOC dynamics more accurately in response to global change.

Radiographic assessment of dental post and core placement at different educational levels in an undergraduate student clinic: a 4-year retrospective study.

Dental post and core is one of the common procedures performed after endodontic treatment. The aim of this study was to radiographically assess the quality of post and core procedures performed by dental students at different education levels in addition to determining the most critical errors encountered during their clinical practice. A retrospective cross-sectional study design was conducted in the College of Dentistry, Imam Abdulrahman Bin Faisal University. A total of 550 periapical radiographs (PAs) of cemented posts were retrieved from the records of patients treated by dental students. Parameters and guidelines for assessing the quality of post treatment have been determined and statistically analyzed. A P value <0.05 was considered statistically significant. The study included 502 students and most of them were females (66.5%). Data were obtained from 502 patients (62% females) with fiber posts used in 98.2% of the cases. About 50% of the posts were inserted in premolars, 62.9% in the upper arch, and 66.7% were restored with crowns as a final restoration. Regarding the quality of posts, 98.4% showed good preparation quality and 98% showed good radiographic quality. The post diameter was equal to 1/3 of the root diameter in 31.9% of the cases; post length was equal to 2/3 of root length in 5% of the cases and equal to or more than crown height in all cases (100%). Length of the remaining gutta percha (GP) was between 3-5 mm in 38.8%, and there was no gap between the post and remaining GP in 95.6% of the cases. There were no statistically significant differences between dental students at different clinical educational levels regarding the quality of post placement. The quality of post and core procedures performed by students showed acceptable radiographic quality and were within the recommended standards.

Above‐ and belowground strategies of tropical montane tree species are coordinated and driven by small‐scale nitrogen availability

Abstract The question whether the strategies of above‐ and belowground plant organs are coordinated as predicted by the plant economics spectrum theory is still under debate. We aim to determine the leading dimensions of tree trait variation for above‐ and belowground functional traits, and test whether they represent spectra of adaptation along a soil fertility gradient in tropical Andean forests. We measured leaf, stem and fine root functional traits, and individual‐level soil nutrient availability for 433 trees from 52 species at three elevations between 1000 and 3000 m a.s.l. We found close coordination between above– and belowground functional traits related to the trade‐off between resource acquisition and conservation, whereas root diameter and specific root length formed an independent axis of covarying traits. The position of a tree species along the acquisition–conservation axis of the trait space was closely associated with local soil nitrogen, but not phosphorus, availability. Our results imply that above‐ and belowground plant functional traits determine at which edaphic microhabitats coexisting tree species can grow, which is potentially crucial for understanding community assembly in species‐rich tropical montane forests. Read the free Plain Language Summary for this article on the Journal blog.

Imaging tree root systems using ground penetrating radar (GPR) data in Brazil

Trees sequester carbon dioxide from the atmosphere through photosynthesis, storing it in branches, stems, and roots, where the belowground carbon fraction, approximately ¼ of the total amount, exhibits significant interspecies root biomass variability. Estimating the amount of carbon stored in tree roots of different species is key to understanding an important aspect of climate change and exploring how natural forests, urban tree planting policies, and reforestation projects might help to address it. In this context, one of the most prominent Non-Destructive Testing methods capable of estimating the diameter and length of roots at different depths is ground penetrating radar (GPR). It has been widely used for geological, archaeological, and geotechnical studies due to its accuracy in locating buried material in different contexts, although standards for the correct management of datasets related to belowground root systems are still been developed. This paper reports a GPR signal processing flow to estimate the root diameter of three species of tropical forest trees, and to demonstrate the method’s viability, a dataset was collected in a study area with a 900 MHz shielded antenna. A multi-stage data processing flow is then presented, including raw data, file format conversion, zero-time adjustment, background removal, signal gain, Stolt FK migration, and time-to-depth conversion with hyperbolic adjustment velocity. The resulting data were converted from true amplitude data to a trace envelope. High amplitudes on the envelope section, with lateral continuity in parallel sections, were interpreted as roots. However, the interpretation of outcomes encounters notable complexities, primarily attributable to the intricate nature of subsurface root architectures, the soil matrix characterized by significant clay content, and the co-occurrence of buried materials proximate to the arboreal subjects. Consequently, amplitudes discerned within ground penetrating radar (GPR) 2D sections necessitate cautious interpretation, as they are not immediately indicative of subsurface roots. To overcome this difficulty, this study used direct measurements of the roots in the field, to confirm the GPR data. Despite these complexities, the study demonstrates GPR’s efficacy, particularly in the uppermost soil layer-a pivotal carbon reservoir with a 96% correlation (R2) between GPR-derived coarse-root diameter estimates and field measurements.

Root traits and biomass production of drought‐resistant and drought‐sensitive arabica coffee varieties growing under contrasting watering regimes

AbstractDrought is a major factor affecting coffee production, and different genotypes exhibit varying degrees of resistance to drought stress. We examined root traits and biomasses of drought‐resistant (74110, Angafa, Bultum, Chala, and Gawe) and drought‐sensitive (75227, Koti, Melko CH2, Menasibu, and Mokah) Coffea arabica varieties at seedling stage under contrasting watering regimes (water stressed and well watered) for 30 days followed by 15 days of recovery to identify the association between drought resistance and root traits and dry matter partitioning, and the impact of drought stress on growth performance of arabica coffee varieties. We used a split‐plot design with three blocks, where watering regime was the whole‐plot factor and variety was the subplot factor. During water‐stress and recovery periods, the interaction effect between watering regime and variety significantly affected root traits and dry matter partitioning, while the watering‐regime main effect affected biomass. We observed a higher (1) tap root diameter (0.34 cm), lateral root number (80.7), and root volume (4.7 cm−3) for 74110; (2) lateral root number (79.3), specific root length (24.8 cm g−1), and root‐mass ratio (0.41 g g−1) for Bultum; and (3) root length density (3.3–5.2 cm cm−3), root angle (42.6°–47.8°), root‐mass ratio (0.40–0.42 g g−1), and root‐shoot ratio (0.67–0.72 g g−1) for Angafa, Chala, and Gawe under water‐stressed condition. During both study periods, biomasses were much lower under water‐stressed than under well‐watered condition. The findings show the association between drought resistance and root traits and dry matter partitioning, and the impact of drought stress on growth performance of young arabica coffee.

Changes in preferential flow caused by root effects in black locust plantations of different stand ages in the semi-arid region of the Loess Plateau

Preferential flow significantly influences regional water cycles, and affecting surface and subsurface runoff processes. By comparing soil infiltration characteristics across various forest ages, it can be evaluated how artificial black locust forests on the Loess Plateau contribute to the resilience of soil and water conservation. In this study, we analyzed the spatial distribution characteristics of roots of black locust plants using field investigations and statistical analyses and determined the effects of the root characteristics on the preferential flow in the semi-arid of the Loess Plateau, China. The results showed that the root biomass, root length density, and root volume ratio of young forests were significantly lower than those of middle-aged and mature forests (P < 0.05), and root characteristic parameters varied significantly among different root diameters and soil layers.. The average volume of decayed root channels in mature forests, accounting for approximately 0.16 % in a unit volume of soil, was 3.1 times that of young forests and 4.9 times that of middle-aged forests. Preferential flow increased with forest age in artificial black locust forests. 2–5 mm, 30–40 mm and > 50 mm roots promoted preferential flow to varying degrees, while roots of 5–15 mm inhibited the preferential flow. < 2 mm, 10–30 mm and 40–50 mm roots has no effect on preferential flow (P > 0.05). The size and density of decayed root channels significantly improve soil preferential flow, and the differences among forest ages are linked to the network created by rotten roots. These findings indicate that living roots of different diameters and decayed roots contribute to soil preferential flow to varying extents. The results provided a conceptual basis for understanding the potential impact of vegetation roots on surface runoff during the vegetation restoration ecosystems process in the Loess Plateau.

Unraveling root and rhizosphere traits in temperate maize landraces and modern cultivars: Implications for soil resource acquisition and drought adaptation.

A holistic understanding of plant strategies to acquire soil resources is pivotal in achieving sustainable food security. However, we lack knowledge about variety-specific root and rhizosphere traits for resource acquisition, their plasticity and adaptation to drought. We conducted a greenhouse experiment to phenotype root and rhizosphere traits (mean root diameter [Root D], specific root length [SRL], root tissue density, root nitrogen content, specific rhizosheath mass [SRM], arbuscular mycorrhizal fungi [AMF] colonization) of 16 landraces and 22 modern cultivars of temperate maize (Zea mays L.). Our results demonstrate that landraces and modern cultivars diverge in their root and rhizosphere traits. Although landraces follow a 'do-it-yourself' strategy with high SRLs, modern cultivars exhibit an 'outsourcing' strategy with increased mean Root Ds and a tendency towards increased root colonization by AMF. We further identified that SRM indicates an 'outsourcing' strategy. Additionally, landraces were more drought-responsive compared to modern cultivars based on multitrait response indices. We suggest that breeding leads to distinct resource acquisition strategies between temperate maize varieties. Future breeding efforts should increasingly target root and rhizosphere economics, with SRM serving as a valuable proxy for identifying varieties employing an outsourcing resource acquisition strategy.

The effect of spraying with marine algae extract and adding Humax on growth traits of the roots of two varieties of pomegranate seed-lings

The study was conducted for the period from 20/3 to 20/9/2023 to study the Effect of spraying marine algae extract and adding Humax on the growth traits of the roots of two varieties of pomegranate seedlings. The experiment was implemented relying on the completely randomized block design (RCBD) as a factorial experiment of three factors: the first was pomegranate varieties (Wonderful and Slimi), the second was marine algae extract with three concentrations (0, 1.5, and 3 ml L-1), and the third was Humax with three concentrations (0, 0.25, and 0.50 g L-1), comprising three replicates of each. On September 20 2023 measurements were taken and the results were analyzed according to the statistical design used, and the averages were compared according to the selection of the least significant difference and at the level of probability 0.05, and the most important results reached: The variety Wonderful was significantly superior to the Slimi variety in most root traits studied except the root diameter trait. The treatment of the marine algae extract at a concentration of 3ml L-1 showed significant superiority for all root traits studied, The Humax treatment at a concentration of 0.50 g L-1 showed significant superiority for all the root traits studied. The binary interaction between the varieties and the marine algae extract significantly affected all studied traits, as the variety Wonderful, when treated with 3ml L-1 increased in most root traits, while cultivar Slimi recoded highest average in the root diameter. The binary interaction between the varieties and Humax was significantly effective; when treating the variety Wonderful with 0.50 g L-1 of Humax increased all root traits significantly. The binary interaction between marine algae extract and Humax significantly affected all root traits. Treating seedlings with 3ml L-1 of marine algae extract and 0.50g L-1 of Humax.

Phenotypic variability in the US upland cotton core set for root traits and water use efficiency at the late reproductive stage

AbstractTo incorporate root traits that improve water use efficiency (WUE) in cotton (Gossypium hirsutum L.) variety development, harnessing the genetic variability for root traits is essential. The objectives of this study were to characterize the US upland cotton core set for root traits and WUE and determine the traits associated with WUE. The core set includes 23 of the 381 accessions of the cotton diversity panel and represents 74% of the allelic diversity in US upland cotton. Plants were grown in polyvinyl chloride columns (125‐cm height, 15‐cm diameter) in a greenhouse in 2021–2022 and 2022–2023. Half of the columns contained a synthetic hardpan (1 cm thickness, 300 PSI penetration resistance) at a depth of 25 cm. Plants were harvested when &gt;50% of the population opened bolls. Based on 16 root‐ and shoot‐traits, water use, and WUE, Deltapine 14, Station Miller, and Southland M1 were the best performers, and Toole, Paymaster HS200, Western Stormproof, CD3HCABCUH‐1‐89, and PD 2164 were the poor performers irrespective of the presence or absence of hardpan stress to root growth. The WUE of the core set genotypes was positively correlated with very fine root (diameter &lt;0.25 mm) length, surface area, and volume and total root weight (correlation coefficient ≥0.45). These traits serve as beneficial root traits for developing new varieties with enhanced WUE. The identified genotypes and traits will be valuable for developing the next generation of water‐use‐efficient cotton varieties with a broad genetic base through advanced breeding techniques involving genomic tools and genetic diversity.

Effects of natural and chemical rooting stimulants on some root traits of two varieties of pomegranate (Punica granatum L.) cuttings

The experiment ran from the middle of February until the start of November 2023 under the plant canopy of the Department of Horticulture and Landscape, College of Agriculture, University of Kerbala. The study employed a Randomized Complete Block Design (R.C.B.D.) as a factorial experiment, with two pomegranate varieties (Yamani and Bashkan) as the first factor and various combinations of natural and chemical rootings as the second factor. These included extracts of moringa leaves (M0, M1) and licorice roots (L0, L1) at concentrations of 0 and 15 g L-1 each, as well as indole butyric acid at a concentration of 0 and 10 mg L-1 (B0, B1). The majority of the root features of the resultant seedlings demonstrated that, overall, the Bashkan variety outperformed the Yamani variety; however, this superiority varied when combined with other rooting combinations. Between the rooting stimulant combinations utilized in the study, the cuttings' dipping results differed. When it came to the quantity, size, and fresh and dry weight of the root system, indole butyric acid in combination with B1M0L0 performed better. It resulted in 250.000 root seedlings-1, 2.270 cm3, 20,680 g, and 6,650 g, respectively. In contrast, the B0M0L1 licorice root treatment demonstrated superior root length, reaching 38,100 cm. Both the percentage of rooting and the average root diameter were the largest in the combination including both extracts, B0M1L1, reaching 5.170% and 1.603 mm, respectively. Given that natural extracts have outperformed chemical radicals in the majority of the rooting qualities under study—such as licorice root extract and moringa leaf extract—it is possible to conclude from the aforementioned results on their suitability for usage as an alternative.

Predicting Marfan Syndrome in Children With Congenital Ectopia Lentis: Development and Validation of a Nomogram.

To derive an effective nomogram for predicting Marfan syndrome (MFS) in children with congenital ectopia lentis (CEL) using regularly collected data. Diagnostic standards (Ghent nosology) and genetic test were applied in all patients with CEL to determine the presence or absence of MFS. Three potential MFS predictors were tested and chosen to build a prediction model using logistic regression. The predictive performance of the nomogram was validated internally through time-dependent receiver operating characteristic curves, calibration curves, and decision curve analysis. Eyes from 103 patients under 20 years old and with CEL were enrolled in this study. Z score of body mass index (odds ratio [OR] = 0.659; 95% confidence interval [CI], 0.453-0.958), corneal curvature radius (OR = 3.397; 95% CI, 1.829-6.307), and aortic root diameter (OR = 2.342; 95% CI, 1.403-3.911) were identified as predictors of MFS. The combination of the above predictors shows good predictive ability, as indicated by area under the curve of 0.889 (95% CI, 0.826-0.953). The calibration curves showed good agreement between the prediction of the nomogram and the actual observations. In addition, decision curve analysis showed that the nomogram was clinically useful and had better discriminatory power in identifying patients with MFS. For better individual prediction, an online MFS calculator was created. The nomogram provides accurate and individualized prediction of MFS in children with CEL who cannot be identified with the Ghent criteria, enabling clinicians to personalize treatment plans and improve MFS outcomes. The prediction model may help clinicians identify MFS in its early stages, which could reduce the likelihood of developing severe symptoms and improve MFS outcomes.

Identification of Novel QTL for Seedling Root Architectural Traits in the D Genome of Natural and Resynthetic Allohexaploid Wheat

Root architectural traits at the seedling stage have been demonstrated to be crucial for the efficient uptake of nutrients and drought tolerance in wheat. To dissect the genetic basis of these traits from the D genome, 182 recombinant inbred lines (RILs) derived from the common wheat TAA10 crossed with resynthesized allohexaploid wheat XX329 possessed similar AABB genomes were used for QTL mapping of five root traits in hydroponic-cultured seedlings, including lateral root number (LRN), seminal root number (SRN), root hair length (RHL), root diameter (RD), and total root volume (TRV). A total of seven QTLs were identified for the five root traits, with six possible novel QTLs for LRN, RHL, RD and TRV, accounting for 4.98–12.17% of phenotypic variation. One QTL (QLrn.qau-5D.2), controlling lateral root number, was fine mapped an approximate 5.0-Mb interval harboring 80 annotated genes, including five auxin-related genes. We further validated that QLrn.qau-5D.2 in NILTAA10 significantly enhanced yield-related traits, such as plant height, spike length, spike compactness, tiller number per plant and grain yield per plant, as comparison with NILXX329. Collectively, these results provide vital insights for fine-mapping QTLs associated with LRN, SRN, RHL, RD and TRV and facilitate the root morphologic designs for enhancing yield performance.

Effect of axillary bud number on stem cuttings of sweet potato cv. 'Blesbok' productivity using sack gardening technology

Increasing urbanisation and the rise in global food prices, which results in severe hunger and micronutrient deficiencies, necessitates the identification of innovative, but affordable vegetable growing-based strategies, that can increase access to food by utilising the limited space available in rural and urban areas. Therefore, sack gardening technology could be a solution to both the lack of arable land and water scarcity in urban and rural areas. The objective of the study was to determine whether axillary bud number will have an effect on the agronomic parameters of sweet potato cv. 'Blesbok' produced using the sack gardening technology. The number of axillary buds per stem cutting, namely, 1 (control), 2, 3, 4, and 5 buds, were arranged in RCBD, with 10 replicates. The number of axillary buds had significant effects on vine length (VL), fresh shoot mass (FSM), number of shoots (NOS) and dry shoot mass (DSM). However, no significant effects were observed on fresh tuberous root mass (FTRM), chlorophyll content (CC), stem diameter (ST), tuberous root diameter (TRL), tuberous root length (TRL), dry tuberous root mass (DTRM) and number of tuberous roots (NTR). Relative to the control VL, FSM and DRM was reduced by 8-37, 30-55 and 26-55%, in stem cuttings having 2, 3, 4 and 5 buds, respectively, whereas the NS was increased by 8-17%. The quadratic relationship models were explained by 95, 92, 96 and 98% in VL, NOS, FSM and DSM, respectively. In conclusion, stem cuttings containing 1 and 2 axillary buds showed better growth parameters when grown under sack gardening technology.

Effect and Mechanism of Root Characteristics of Different Rice Varieties on Methane Emissions

Methane (CH4), which is an important component of the greenhouse gases from paddy ecosystems, is a major contributor to climate change. CH4 emissions from paddy ecosystems are closely related to the rice root system; however, how the rice root system affects CH4 emissions remains unclear. We conducted a field experiment in 2023 at the Heping Irrigation District Rice Irrigation Experiment Station in Qing’an County, Heilongjiang Province. The field experiment used five local rice varieties with similar fertility periods to observe rice root morphology and physiology indexes, CH4 emission fluxes, and cumulative CH4 emissions. A structural equation model (SEM) was established to investigate the effects of root characteristics on the CH4 emissions from rice and understand the potential mechanisms of these effects. The results showed that the seasonal patterns of CH4 emission fluxes were similar in different rice varieties, and that, during the tillering to heading–flowering stages, the cumulative CH4 emissions accounted for 89.8–92.6% of the total cumulative CH4 emissions of rice. Significant negative correlations were observed between CH4 emission fluxes and root volume, root dry weight, root oxidation activity (ROA), and root radial oxygen loss (ROL) (r = −0.839, −0.885, −0.401 and −0.934, p &lt; 0.05), while there were significant positive correlations between root diameter; malic acid, citric acid, and succinic acid contents; and CH4 emission fluxes (r = 0.407, 0.753, 0.797, and 0.685, p &lt; 0.05). The SEM showed that CH4 emission fluxes were directly influenced by ROL and organic acid contents, while the other root indicators had indirect effects by modulating ROL and organic acid contents. ROL and root volume had the largest total effect, indicating that ROL and root volume were the most significant root physiological and morphological indicators affecting CH4 emission fluxes. This study provides theoretical support and reference data for achieving sustainable agricultural development in the black soil region of Northeast China.

Variation in root traits and phenotypic plasticity between native and introduced populations of the invasive plant Chromolaena odorata

Understanding intraspecific trait variations, particularly for invasive species that occupy large geographic areas with different resource conditions, can enhance our understanding of plant responses to changes in environmental resources. However, most related studies have focused on aboveground traits, while variations in root traits and responses to changes in resources during biological invasion have not been clarified. To fill this knowledge gap, we compared the root traits of Chromolaena odorata from 10 introduced populations in Southeast Asia and 12 native populations in North and Central America under different soil nutrients. The introduced populations of the invader exhibited greater resource-acquisitive root traits, characterized by reduced fine root diameter but increased proportions of absorbing root length and specific root length, compared to the native populations. Although nutrient addition significantly affected root traits, the introduced populations showed greater phenotypic plasticity in four traits (root / shoot ratio, specific root length, absorbing root length proportion, and branching intensity) than the native populations. Different root trait syndromes were observed between the introduced and native populations. These results indicate that after introduction, C. odorata may shift towards a more soil resource-acquisitive strategy and thus respond more positively to increased soils nutrients, thereby showing better performance in high-resource environments. This study provides a better understanding of how species respond to environment changes and reveals the factors underlying exotic plant invasion success.

Elucidating the genomic regions through genome-wide association study (GWAS) for root traits in cowpea (Vigna unguiculata (L) Walp) mini-core collection

Enhancing the root traits through selection and breeding efforts can significantly improve the acquisition of soil resources, consequently boosting crop production in marginal environments. Cowpea is one of the important legume crops in arid and semi-arid regions, grown mostly in marginal environments under drought conditions. The roots play a crucial role in plant's ability to survive and adapt under such water stressed conditions. The understanding of cowpea genetic architecture related to root system architecture (RSA) remains limited due to difficulties in accurately measuring root traits. In the present study, a set 110 diverse mini-core collection of cowpea from IITA, Nigeria was evaluated for thirteen (13) different root-shoot traits under controlled conditions in the green house. Significant variation was recorded for all the root traits in the mini-core set. Most promising genotype for most of the root traits, viz., root volume, dry root weight, root biomass density and tap root diameter were identified. The correlation analysis revealed significant positive association (p < 0.001) of root weight with shoot weight (0.85), root volume (r = 0.61), and tap root diameter (0.56). In the principal component analysis (PCA), first three principal components explained the variance of 64.31%, with PC1 contributing 44.43%, PC2 10% and PC3 9.88%. All the root-shoot traits contribute positive variation to PC1especially dry root weight and dry shoot weight that had high component loading and in PC2 root shoot ratio had high loading. The root-shoot trait data was used with 6,574 good quality SNP data for discovery of genes/QTLs/marker-trait associations for root traits. The analysis of results of genome wide association study (GWAS) led to the identification of 52 unique SNPs associated significantly (p < 10−4) with thirteen root-shoot traits. Highest number of SNPs was found associated with root weight and chromosome 5 was identified as SNP hotspot for harboring majority of significant SNPs. We further delve candidate genes within 50 kb around the identified SNP that led to the identification of several important candidate genes underlying genomic regions responsible for root-shoot traits in cowpea. The promising cowpea genotypes for root traits and promising MTAs/candidate genes will prove useful in cowpea improvement programs including improvement of drought tolerance in cowpea.

Genetic Divergence of Ashwagandha (Withania somnifera (L.) Dunal) for Growth and Yield Traits

Genetic divergence among 32 Ashwagandha (Withania somnifera (L.) Dunal) accessions of different geographic origins was assessed using Mahalanobis D2 statistics. Observations revealed significant genotypic differences, and accordingly, genotypes were classified into six clusters. Cluster I was the largest, with twenty genotypes, followed by the cluster II, which has eight, and clusters III, IV, V, and VI contained only one most divergent genotype. The maximum divergence was observed between clusters II and III (D2 = 47.90), followed by clusters V and VI (D2 = 43.95), and clusters III and VI (D2 = 42.29). Cluster IV had the least inter-cluster distance (D2 = 22.82) with cluster VI. Clusters III, IV, V, and VI had only one genotype each, and hence, the intra-cluster distance was zero. The genotype of cluster V was unique as it had the highest values for fresh and dry root weight per plant, diameter and length of the main root, number of secondary roots per plant, number of berries per plant, and girth of stem with a high seed yield per plant. Cluster VI was desirable in respect of days to 50 per cent flowering and days to root harvest. Cluster II exhibited the highest value for height of plant and branches per plant. Cluster IV had the highest mean values for the number of seeds per berry. Thus, hybridization among these genotypes can generate desirable transgressive segregants. Aim of Studies: To assess the genetic divergen of Withania somnifera. Place and Duration of Study: Department of Horticulture, College of Agriculture, UAS, GKVK, Bengaluru from 2020-21 to 2021-22. Methodology: The genetic divergence between the genotypes in the population was estimated using formula D2= p (Yit - Yjt) and genetic divergence among 32 Ashwagandha (Withania somnifera (L.) Dunal) accessions of different geographic origins was assessed using Mahalanobis D2 statistics. Observations revealed significant genotypic differences, and accordingly. Results: Observations revealed significant genotypic differences, and accordingly, genotypes were classified into six clusters. Cluster I was the largest, with twenty genotypes, followed by the cluster II, which has eight, and clusters III, IV, V, and VI contained only one most divergent genotype. The maximum divergence was observed between clusters II and III (D2 = 47.90), followed by clusters V and VI (D2 = 43.95), and clusters III and VI (D2 = 42.29). Cluster IV had the least inter-cluster distance (D2 = 22.82) with cluster VI. Clusters III, IV, V, and VI had only one genotype each, and hence, the intra-cluster distance was zero. The genotype of cluster V was unique as it had the highest values for fresh and dry root weight per plant, diameter and length of the main root, number of secondary roots per plant, number of berries per plant, and girth of stem with a high seed yield per plant. Cluster VI was desirable in respect of days to 50 per cent flowering and days to root harvest. Cluster II exhibited the highest value for height of plant and branches per plant. Cluster IV had the highest mean values for the number of seeds per berry Conclusion of finding: Significant genetic divergence and complementarity for most features has been shown by the genotypes of clusters II and III and clusters V and VI. This could lead to significant genetic improvement for particular characters and their selection for new varieties.

Optimizing the evaluation of root system architectural traits in Brassica napus

A semi-hydroponic system was developed to assess canola ( Brassica napus L.) root architectural traits. Four cultivars were grown under controlled conditions in germination paper rolls immersed in half-strength Hoagland’s solution. Eight parameters, including total root length, total root surface area, average root diameter, tip number, total primary root length, total lateral root length, total tertiary root length, and basal link length, were analyzed using the WinRHIZO software after 7, 14, and 21 days. The results suggested that 14 days in the semi-hydroponic system were optimal for accurate root trait assessment, as clear differences were observed while maintaining ease of handling and scanning.