Intermediate Root Research Articles

Analysis of Root Angulation of Maxillary Central Incisor Using Cone Beam Computed Tomography (CBCT)

Background: Variance in anatomical morphology is influenced by the axial inclination of the tooth. When looking at the axial tilt of the crown, it's common to assume that it follows the same axis as the root. This study aims to use Cone Beam Computed Tomography (CBCT) to determine the root angulation correlation in maxillary central incisors. Methods: This cross-sectional observational research was performed at Dow University of Health Sciences (DUHS). The CBCT scans of patients who matched the inclusion criteria were done by skilled radiography technicians and primary investigators on ROTOGRAPH EVO 3D. For statistical analysis, one-way ANOVA was utilized to examine the Root Angulation (RA) with different root positions. p-value <0.05 was considered significant. Results: This study examined n=152 CBCT images. Mean age was 27.2 + 5.9 years, with 32(42.1%) men and 44(44.1%) females. Buccal subtype I was most prevalent (59, 38.8%) in maxillary central incisors, while buccal subtype III was least common (5, 3.3%). The root angulations varied significantly between root location classifications (p=0.007). These were intermediate root location (14.9 2.6 degrees) and buccal subtype III (14.28 2.25 degrees). The palatal root type had the least angle (3.73 1.5 degrees). Conclusion: The buccal root position was shown to be the most common root location. Buccal subtype I was by far the most common. Buccal subtype III and middle root location had the maximum root angle. The palatal root position had the smallest angle.

Variations of azygos vein: a cadaveric study with clinical relevance.

The azygos vein can be formed as a single root, two roots, and three roots, namely lateral, intermediate and the medial roots respectively. The hemiazygos vein and the accessory hemiazygos vein are the tributaries of azygos vein rather than its left side equivalents. Its variations, especially in young persons without any relevant risk factors, may result in thromboembolic illness. This study aimed to describe the morphological and morphometric variations of azygos system of veins. The present study was conducted on thirty formalin fixed adult human cadavers by dissecting azygos vein from formation to termination and variations were noted. The azygos vein was formed by a single root in 56.7%, by two roots: the lateral root and intermediate root in 36.7% cases and by the lateral root and medial root in 6.6%. The vertebral level of termination of azygos vein was seen at the level of T4 vertebrae in 70% cases, at the level of T3 vertebrae in 20% of cases and at the level of T5 vertebrae in 10% cases. The course of azygos vein was varying in 13.3%. These morphological variations can be useful while performing mediastinal surgery, mediastinoscopy, surgery of the deformations of the vertebral column, neurovascular surgeries of the retroperitoneal organs, disc herniation and fracture of thoracic vertebrae.

Soil compaction effects on arbuscular mycorrhizal symbiosis in wheat depend on host plant variety

Background and aimsSupporting arbuscular mycorrhizal (AM) nutrient acquisition in crops may reduce the need for fertilizer inputs, leading to more cost effective and sustainable crop production. In wheat, AM fungal responsiveness and benefits of symbiosis vary among varieties. This study explored the role of soil compaction in this variation.MethodsWe examined in a field experiment how soil compaction affects AM fungal colonization and biomass in five spring wheat varieties, and how these varieties differ in their AM-mediated phosphorus (P) uptake. We also studied soil properties, and AM fungal community composition in roots and soil.ResultsSoil compaction increased AM fungal colonization in the variety Alderon, characterized by root traits that indicate inefficient P uptake. Wheat P concentration and P:N ratio in Alderon and Diskett increased with increased root AM fungal colonization and biomass. In Diskett, which is the most cultivated spring wheat variety in Sweden and has intermediate root traits, total P content per m2 also increased with root AM fungal colonization and biomass.ConclusionsSome wheat varieties, potentially those characterized by P inefficient root traits, such as Alderon, may depend more on AM-mediated P uptake in compacted than in non-compacted soil. Increased P uptake with increased AM fungal colonization in Diskett suggests that efficient root and AM-mediated nutrient uptake can occur simultaneously in a modern variety. Breeding varieties that use roots and AM symbiosis as complementary strategies for nutrient uptake could improve nutrient uptake efficiency and help farmers achieve stable yields in varying conditions.

Cytokinin application improving growth, sugar content, polyphenol and flavonoid content in Yacon tuberous roots

Yacon is a tuberous crop that accumulates sugar in large quantities and has many valuable secondary compounds in medicine such as phenolic compounds and flavonoids. The objective of this study was to increase the size and content of sugars, polyphenols and flavonoids during the early growth of tubers. Therefore, early tuber stimulation and tuber size are important as they determine yield over time. Cell restructuring along with growth expansion as well as control of tuber reserves also takes place. This study investigated anatomy structure changes, fresh weight, dry weight, respiratory intensity and sugar content in different Yacon root types. A spray of N-benzyl adenine (BA) (0–25 ppm) is applied in the initial stage. Determining agronomic, physiological, and, biochemical indicators after 4 weeks of treatment, the sugar content of tubers determines the yield of tubers after 16 weeks of treatment. The results showed that Yacon crops at the stages of 5 to 9 weeks develop fibrous roots, thin fibrous roots and pre-tuberous roots at week 13, intermediate storage roots at week 17 and mature storage roots at week 17. BA 20 ppm application on Yacon crop week 13 increased the number of storage roots, fresh weight, dry weight tuber diameter, total sugar content, fructan content, total phenolic and flavonoid remarkably compared to controls, but reducing sugar content is lower than treating BA at 15 ppm. BA 20 ppm application on Yacon crop week 13 increased the parameters of sugar growth and accumulation, tuber yeild on a plant increased 2 times, dry weight increased 1.65 times, sugar content, total sugar 1.12 times, reducing sugar 3.01 times, fructan 1.36 times, total phenolic and flavonoid 1.36 and 1.26 times after 25 weeks of treatment.

Phenotypic variation of root-system architecture under high P and low P conditions in potato (Solanum tuberosum L.)

BackgroundPhosphorus (P) is an essential macronutrient required for plant metabolism and growth. Its acquisition by plants depends on the availability of dissolved P in the rhizosphere and on the characteristics of P uptake mechanisms such as root-system architecture (RSA). Compared to other crops, potato (Solanum tuberosum L.) has a relatively poor P acquisition efficiency. This is mainly due to its shallow and sparsely branched root system, resulting in a rather limited exploitable soil volume. Information about potato genotypes with RSA traits suitable to improve adaptation to nutrient scarcity is quite rare. Aim of this study is to assess phenotypic variation of RSA in a potato diversity set and its reactions to P deficiency.ResultsOnly one out of 22 RSA-traits showed a significant increase under low-P conditions. This indicates an overall negative effect of P scarcity on potato root growth. Differences among genotypes, however, were statistically significant for 21 traits, revealing a high variability in potato RSA. Using a principal component analysis (PCA), we were able to classify genotypes into three groups with regard to their root-system size. Genotypes with both small and large root systems reacted to low-P conditions by in- or decreasing their relative root-system size to medium, whereas genotypes with an intermediate root system size showed little to no changes.ConclusionsWe observed a huge variation in both the potato root system itself and its adaptation to P deficiency. This may enable the selection of potato genotypes with an improved root-zone exploitation. Eventually, these could be utilized to develop new cultivars adapted to low-P environments with better resource-use efficiencies.

Definition of the Region of Interest for the Assessment of Alveolar Bone Repair Using Micro-computed Tomography.

The objective of this study was to evaluate the influence of the extraction socket (distal or lingual root) and the type of region of interest (ROI) definition (manual or predefined) on the assessment of alveolar repair following tooth extraction using micro-computed tomography (micro-CT). The software package used for scanning, reconstruction, reorientation, and analysis of images (NRecon®, DataViewer®, CT-Analyzer®) was acquired through Bruker < https://www.bruker.com > . The sample comprised the micro-CT volumes of seven Wistar rat mandibles, in which the right first molar was extracted. The reconstructed images were analyzed using the extraction sockets, i.e., the distal and intermediate lingual root and the method of ROI definition: manual (MA), central round (CR), and peripheral round (PR). The bone volume fraction (BV/TV) values obtained were analyzed by two-way ANOVA with Tukey's post hoc test (α = 5%). The distal extraction socket resulted in significantly lower BV/TV values than the intermediate lingual socket for MA (P = 0.001), CR (P < 0.001), and PR (P < 0.001). Regarding the ROI, when evaluating the distal extraction socket, the BV/TV was significantly higher (P < 0.001) for MA than for CR and PR, with a lower BV/TV for CR. However, no significant difference was observed for MA (P = 0.855), CR (P = 0.769), or PR (P = 0.453) in the intermediate lingual extraction socket. The bone neoformation outcome (BV/TV) for alveolar bone repair after tooth extraction is significantly influenced by the ROI and the extraction socket. Using the predefined method with a standardized ROI in the central region of the distal extraction socket resulted in the assessment of bone volume, demonstrating the most critical region of the bone neoformation process.

Objective Phenotyping of Root System Architecture Using Image Augmentation and Machine Learning in Alfalfa (Medicago sativa L.).

Active breeding programs specifically for root system architecture (RSA) phenotypes remain rare; however, breeding for branch and taproot types in the perennial crop alfalfa is ongoing. Phenotyping in this and other crops for active RSA breeding has mostly used visual scoring of specific traits or subjective classification into different root types. While image-based methods have been developed, translation to applied breeding is limited. This research is aimed at developing and comparing image-based RSA phenotyping methods using machine and deep learning algorithms for objective classification of 617 root images from mature alfalfa plants collected from the field to support the ongoing breeding efforts. Our results show that unsupervised machine learning tends to incorrectly classify roots into a normal distribution with most lines predicted as the intermediate root type. Encouragingly, random forest and TensorFlow-based neural networks can classify the root types into branch-type, taproot-type, and an intermediate taproot-branch type with 86% accuracy. With image augmentation, the prediction accuracy was improved to 97%. Coupling the predicted root type with its prediction probability will give breeders a confidence level for better decisions to advance the best and exclude the worst lines from their breeding program. This machine and deep learning approach enables accurate classification of the RSA phenotypes for genomic breeding of climate-resilient alfalfa.

Simulating rhizodeposition patterns around growing and exuding root systems

Abstract In this study, we developed a novel model approach to compute the spatio-temporal distribution patterns of rhizodeposits around growing root systems in three dimensions. This model approach allows us to study the evolution of rhizodeposition patterns around complex three-dimensional root systems. Root systems were generated using the root architecture model CPlantBox. The concentration of rhizodeposits at a given location in the soil domain was computed analytically. To simulate the spread of rhizodeposits in the soil, we considered rhizodeposit release from the roots, rhizodeposit diffusion into the soil, rhizodeposit sorption to soil particles and rhizodeposit degradation by microorganisms. To demonstrate the capabilities of our new model approach, we performed simulations for the two example rhizodeposits mucilage and citrate and the example root system Vicia faba. The rhizodeposition model was parameterized using values from the literature. Our simulations showed that the rhizosphere soil volume with rhizodeposit concentrations above a defined threshold value (i.e. the rhizodeposit hotspot volume) exhibited a maximum at intermediate root growth rates. Root branching allowed the rhizospheres of individual roots to overlap, resulting in a greater volume of rhizodeposit hotspots. This was particularly important in the case of citrate, where overlap of rhizodeposition zones accounted for more than half of the total rhizodeposit hotspot volumes. Coupling a root architecture model with a rhizodeposition model allowed us to get a better understanding of the influence of root architecture as well as rhizodeposit properties on the evolution of the spatio-temporal distribution patterns of rhizodeposits around growing root systems.

Intragenic complementation at the Lotus japonicus CELLULOSE SYNTHASE-LIKE D1 locus rescues root hair defects.

Root hair cells form the primary interface of plants with the soil environment, playing key roles in nutrient uptake and plant defense. In legumes, they are typically the first cells to become infected by nitrogen-fixing soil bacteria during root nodule symbiosis. Here, we report a role for the CELLULOSE SYNTHASE-LIKE D1 (CSLD1) gene in root hair development in the legume species Lotus japonicus. CSLD1 belongs to the cellulose synthase protein family that includes cellulose synthases and cellulose synthase-like proteins, the latter thought to be involved in the biosynthesis of hemicellulose. We describe 11 Ljcsld1 mutant alleles that impose either short (Ljcsld1-1) or variable (Ljcsld1-2 to 11) root hair length phenotypes. Examination of Ljcsld1-1 and one variable-length root hair mutant, Ljcsld1-6, revealed increased root hair cell wall thickness, which in Ljcsld1-1 was significantly more pronounced and also associated with a strong defect in root nodule symbiosis. Lotus japonicus plants heterozygous for Ljcsld1-1 exhibited intermediate root hair lengths, suggesting incomplete dominance. Intragenic complementation was observed between alleles with mutations in different CSLD1 domains, suggesting CSLD1 function is modular and that the protein may operate as a homodimer or multimer during root hair development.

Synergy between a shallow root system with a DRO1 homologue and localized P application improves P uptake of lowland rice

Improved phosphorus (P) use efficiency for crop production is needed, given the depletion of phosphorus ore deposits, and increasing ecological concerns about its excessive use. Root system architecture (RSA) is important in efficiently capturing immobile P in soils, while agronomically, localized P application near the roots is a potential approach to address this issue. However, the interaction between genetic traits of RSA and localized P application has been little understood. Near-isogenic lines (NILs) and their parent of rice (qsor1-NIL, Dro1-NIL, and IR64, with shallow, deep, and intermediate root growth angles (RGA), respectively) were grown in flooded pots after placing P near the roots at transplanting (P-dipping). The experiment identified that the P-dipping created an available P hotspot at the plant base of the soil surface layer where the qsor1-NIL had the greatest root biomass and root surface area despite no genotyipic differences in total values, whereby the qsor1-NIL had significantly greater biomass and P uptake than the other genotypes in the P-dipping. The superior surface root development of qsor1-NIL could have facilitated P uptakes from the P hotspot, implying that P-use efficiency in crop production can be further increased by combining genetic traits of RSA and localized P application.

Bacillus subtilis changes the root architecture of soybean grown on nutrient-poor substrate

The potential of Bacillus subtilis in promoting soybean growth under conditions of low availability of nutrients was assessed in a pot experiment. The experiment was carried out in a completely randomized design with five treatments, as follow: (T1) Bradyrhizobium japonicum; (T2) B. japonicum + non-inoculated organic fertilizer; (T3) B. japonicum + inoculated organic fertilizer; (T4) B. japonicum + B. subtilis; and (T5) B. japonicum + NPK. All inoculated treatments were applied directly to the soybean seeds. Soybean was grown in a controlled growth chamber and, on the 40th day, plants were collected and evaluated. B. subtilis increased root dry weight, root:shoot ratio, number of nodules, and specific nodulation, while chemical fertilization increased the shoot biomass and leaf area. The presence of B. subtilis in the substrate was confirmed by the highest number of colonies found in the inoculated treatment. B. subtilis contributed to higher chlorophyll content and it was similar to treatment with chemical fertilization. The roots length, surface, and volume increased with the chemical fertilization and with B. subtilis. Also, B. subtilis modified the partitioning of assimilates in soybean with an increase in root biomass and changes in root architecture due to the increase in the surface of intermediate roots. This study reinforces that co-inoculation of soybean with Bradyrhizobium and B. subtilis is an efficient strategy to improve plant growth due to their beneficial effects in root architecture, which can contribute to higher uptake of water and nutrients.

Contrasting effects of nitrogen addition on rhizosphere soil CO2, N2O, and CH4 emissions of fine roots with different diameters from Pinus tabulaeformis forest using laboratory incubation.

Nitrogen (N) addition has variable effects on chemical composition, function, and turnover of roots with different diameters. However, it is unclear whether N addition has variable effects on greenhouse gas (GHG) emission in rhizosphere soil. We performed N addition (0-9gNm-2 y-1) experiment in a Pinus tabulaeformis forest and a lab-incubation experiment to determine the effects of N addition on carbon dioxide (CO2), nitrous oxide (N2O), and methane (CH4) emissions in rhizosphere soils of roots with different diameters (very fine roots: <0.5mm, intermediate fine roots: 0.5-1.0mm, largest fine roots: 1.0-2.0mm). Nitrogen addition significantly promoted CO2 emission and CH4 uptake, with maximum values (CO2, 623.15mg C kg soil-1; CH4, 1794.49μg C kg soil-1) in the 6 or 9gNm-2 y-1 treatments (P<0.05). Nitrous oxide emissions were inhibited, with the greatest inhibitory effect in the 9gNm-2 y-1 treatment (48.63μgNkg soil-1). Total phosphorus (TP) content significantly decreased and increased in rhizosphere soil and non-rhizosphere soil after N addition, respectively, while organic carbon (OC), total N (TN), ammonium (NH4+), and nitrate (NO3-) contents in rhizosphere soil increased. A greater change in chemical properties occurred in rhizosphere soil of largest fine roots than very fine roots. Carbon dioxide and nitrous oxide emissions in rhizosphere soil among root sizes exhibited similar responses to N addition. While CH4 uptake was more responsive to N addition in rhizosphere soil with very fine roots than with largest fine roots. Basically, OC, TN, NO3-, and NH4+ were key soil components driving GHG emissions; NO3- promoted CH4 uptake and N2O emissions, NH4+ inhibited CO2 emissions. GHG response to N addition varied greatly, particularly in rhizosphere soil with different root sizes mainly related to its chemical properties.

Transcriptome analysis of apple rootstocks with different stem-root gravitropic setpoint angles

ABSTRACT Our objective was to study the differentially expressed genes (DEGs) of apple (Malus. sp.) rootstock with different gravitropic setpoint angles (GSAs), during the formation of stem-root GSAs. The annual shoots of eight years hybrid seedlings of Malus pumila‘Ralls’ and M. sp. were used as experimental materials, and softwood cutting was carried out in mid-May. Different strains of adventitious root GSA were screened and shoot cuttings were carried out again the following year. The cuttings were randomly selected at 24 day after cutting, and then the transcriptome analysis was carried out. The results show that: (1) according to the difference of stem-root GSA of cutting seedlings, the seedlings of apple rootstock were divided into 3 groups: deep root type (SC), intermediate root type (ZC) and shallow root type (QC). (2) Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis revealed that 2613 genes from shallow- and deep-rooted rootstock, 2091 from deep- and intermediate-rooted rootstock, and 3114 from intermediate- and shallow-rooted rootstock, were annotated into 125 pathways. Among these pathways, plant hormone signal transduction, biosynthesis of secondary metabolites, and phenylpropanoid biosynthesis pathways were significantly enriched (P < 0.01).

Root angle modifications by the DRO1 homolog improve rice yields in saline paddy fields

The root system architecture (RSA) of crops can affect their production, particularly in abiotic stress conditions, such as with drought, waterlogging, and salinity. Salinity is a growing problem worldwide that negatively impacts on crop productivity, and it is believed that yields could be improved if RSAs that enabled plants to avoid saline conditions were identified. Here, we have demonstrated, through the cloning and characterization of qSOR1 (quantitative trait locus for SOIL SURFACE ROOTING 1), that a shallower root growth angle (RGA) could enhance rice yields in saline paddies. qSOR1 is negatively regulated by auxin, predominantly expressed in root columella cells, and involved in the gravitropic responses of roots. qSOR1 was found to be a homolog of DRO1 (DEEPER ROOTING 1), which is known to control RGA. CRISPR-Cas9 assays revealed that other DRO1 homologs were also involved in RGA. Introgression lines with combinations of gain-of-function and loss-of-function alleles in qSOR1 and DRO1 demonstrated four different RSAs (ultra-shallow, shallow, intermediate, and deep rooting), suggesting that natural alleles of the DRO1 homologs could be utilized to control RSA variations in rice. In saline paddies, near-isogenic lines carrying the qSOR1 loss-of-function allele had soil-surface roots (SOR) that enabled rice to avoid the reducing stresses of saline soils, resulting in increased yields compared to the parental cultivars without SOR. Our findings suggest that DRO1 homologs are valuable targets for RSA breeding and could lead to improved rice production in environments characterized by abiotic stress.

Root system architecture in genetically diverse populations of grain sorghum compared with shallow and steeply rooted monocultures

AbstractThe genetic uniformity of monocultures extends belowground to the genetic controls over the architectural configuration of the root system. We hypothesized this may encourage inefficiency in resource acquisition compared with crops with diversity in root system architecture among plants. Here, we report on an evaluation of root systems in grain sorghum [Sorghum bicolor (L.) Moench] populations phenotyped by crown root angle as “shallow” and “steep” rooted, and diverse mixtures (shallow, intermediate, and steep), at four N rates (0, 20, 100, and 200 kg N ha−1) in a sandy soil with a plow layer. Differences in the spatial distribution of root mass among architecturally contrasting populations were confirmed by direct measures in the field, which has not been previously reported in sorghum. This confirmation, plus confirmation of differences in root N distribution with soil depth, indicate that soil C and N dynamics would differ among sorghum populations differing in root system architecture. Patterns in root length density (RLD) by N rate indicated N‐based limitation on root proliferation at low N levels and a N‐induced suppression of proliferation at high N levels. There was no strong evidence that diverse architectural mixtures would result in tangible improvements in resource acquisition, as they generally had intermediate root mass and did not differ in RLD relative to architecturally contrasting monocultures. The similarity of RLD across rooting architectural types was one of several observed indicators of root growth plasticity, which could be a mechanism to alleviate physical constraints of the plants’ inherent first‐order rooting structure in taking up soil resources.

Experimental evaluation of the potential of arbuscular mycorrhiza to modify nutrient leaching in three arable soils located on one slope

Arbuscular mycorrhizal fungi (AMF) were previously shown to decrease nutrient losses by leaching from grassland soils, but no information is available for arable soils. Therefore, the objective of our study was to evaluate the potential of arbuscular mycorrhiza to modify nitrogen and phosphorus cycling including nitrate and phosphate leaching in arable soils. To this end, we established a pot experiment with maize (Zea mays L.) grown in three soils sampled along a sloping field and differing in phosphorus availability and texture. The plants were either inoculated with the native microbial community of the soil, with a pot-cultured AMF isolate, or grown without AMF.Phosphate and nitrate leaching varied among the three soils according to phosphorus availability and plant growth, both being highest in the soil with the highest sand and phosphorus contents. Nitrate leaching was significantly increased by the soils' native microbial communities, which induced higher net nitrification rates as compared to the treatments inoculated with the pot-cultured microbial communities. Mycorrhiza was formed in all three soils after AMF inoculation, with low to intermediate root colonization levels. However, it had no effect on plant growth or nutrient uptake in any of the three soils, which was consistent with a significant nitrogen deficiency of the maize plants. The absence of mycorrhizal effects on nitrate and phosphate leaching is discussed within this context, and the potential of arbuscular mycorrhiza to reduce nutrient leaching from arable soils is concluded low.

Effect of nitrogen addition on the decomposition and release of compounds from fine roots with different diameters: the importance of initial substrate chemistry

Initial substrate chemical characteristics are the most important factor in the regulation of fine root decomposition. However, it remains unclear how nitrogen (N) deposition changes the decomposition process by affecting initial substrate chemical characteristics with different fine root diameter sizes. We compared the root decomposition processes across three diameter sizes (very fine roots, 0.05), but low N addition enhanced the correlation coefficients between initial chemical indexes and decomposition rates. (3) Low N addition increased the release rates of C and cellulose in the very fine roots but not intermediate fine and largest fine roots, while the medium and high N addition decreased the release rates of N, P, cellulose and lignin in the very fine and intermediate fine roots by affecting the initial C, N, P, starch, cellulose and lignin concentrations. (4) Release of compounds from large diameter fine roots is less responsive to N addition than that from the small ones. The initial substrate chemistry plays an important role during the N addition affecting fine root decomposition and release of chemical compounds. Our results suggest that N deposition may change the biogeochemical processes of forest ecosystems by affecting the release of compounds from fine roots.

Anatomy of the Tarsal Canal and Sinus in Relation to the Subtalar Joint Capsule.

Anatomical knowledge of the tarsal canal and sinus is still unclear owing to the complexity of the ligamentous structures within them, particularly the relationship with the capsules of the subtalar joints. The aim of this study was to examine the anatomical relationship between the fibrous tissues of the tarsal canal and sinus and the articular capsules of the subtalar joint. We conducted a descriptive anatomical study of 21 embalmed cadaveric ankles. For a macroscopic overview of the subtalar joint, we removed the talus in 18 ankles and separated the fibrous tissues from the surrounding connective tissues to analyze the layered relationship between the inferior extensor retinaculum (IER) and the subtalar joint capsule. Additionally, we histologically analyzed the tarsal canal and the medial and lateral sides of the tarsal sinus using Masson's trichrome staining in 3 ankles. The medial and intermediate roots of the IER and interosseous talocalcaneal ligament (ITCL) were located in the same layer and were connected to each other, between the capsules of the posterior talocalcaneal and talocalcaneonavicular joints. The intermediate root of the IER and the cervical ligament (CL) had adjacent attachments on the tarsal sinus, and synovial tissues originating from the joint capsules filled the remaining area in the tarsal canal and sinus. We determined that the tarsal canal and sinus tarsi contained 3 layered structures: the anterior capsule of the posterior talocalcaneal joint, including the anterior capsule ligament; the layer of ITCL and IER; and the posterior capsule of the talocalcaneonavicular joint, including the CL. The results of this study may help with the understanding of the pathomechanism of subtalar instability and sinus tarsi syndrome, resulting in better treatment.

Helianthus porteri, a Granite Outcrop Endemic, Does Not Have More Drought Resistant Traits Than Congeners

AbstractHelianthus porteri, a sunflower endemic to drought prone granite outcrops, has been hypothesized to be drought resistant. We compared H. porteri to three Helianthus species (H. annuus, H. agrestis, H. carnosus) from less drought prone habitats for traits associated with drought avoidance and tolerance in greenhouse experiments. Under well-watered conditions, H. porteri had high specific root length suggestive of high capacity for water uptake, but intermediate root mass ratio (RMR) and shallow rooting inconsistent with enhanced capacity for drought avoidance. In response to mild drought, none of the species exhibited osmotic adjustment, and H. porteri had no change in RMR and no greater capacity to increase water-use efficiency, again, inconsistent with greater drought avoidance. In response to cessation of watering, H. porteri wilted at a leaf water potential similar to a wet habitat species, inconsistent with greater drought tolerance. Overall, under the conditions assessed, we found no evidence that H. porteri possesses traits that confer a unique ability to avoid or tolerate drought as compared to congeners.

The response of Phragmites to fluctuating subsurface water levels in constructed stormwater management systems

Area-efficient constructed systems for stormwater management and bioretention may involve large fluctuations in subsurface water levels. Such fluctuations challenge vegetation by forcing roots to explore deeper layers to access water during dry periods. In a controlled experiment, we studied growth patterns and the ability of Phragmites australis roots to track subsurface water level fluctuations of differing amplitude and frequency in substrates with contrasting water-holding capacity. We found that P. australis was able to adjust its rooting pattern to considerable subsurface water level fluctuations (to well below 120cm), but that substrate characteristics can restrict its ability to adjust to larger fluctuations. Fluctuation amplitude was the driving factor for plant growth and biomass allocation responses, while substrate characteristics and fluctuation frequency were less important. When not exposed to large water level fluctuations, P. australis grew larger shoots and only explored intermediate rooting depths. There was a negative relationship between root and rhizome biomass, showing a resource-based trade-off and short-term costs of adjusting rooting patterns to large water level fluctuations. These results indicate that P. australis is suited for systems with considerable subsurface water fluctuations, but constraints on its flexibility need to be investigated.