Root Diameter Research Articles

Effects of soil physical ameliorants on the growth and root morphology of Prunus yedoensis and Ginkgo biloba seedlings in compacted soils

ABSTRACT Soil compaction is prevalent in forest ecosystems, it alters the physical structure of the soil and impedes tree growth. Although ameliorants are known to enhance soil properties and positively influence tree growth, studies remain limited on the effects of potential factors on root development in compacted soils after amelioration. This study aimed to examine the effects of the physical ameliorant treatments BIOC (compaction + biochar) and ORGF (compaction + organic fertilizer) on the soil properties, growth, and root development of Prunus yedoensis and Ginkgo biloba seedlings in compacted soils. We found that ameliorant treatments improved physicochemical soil conditions, such as bulk density, porosity, permeability, pH, total carbon, and total nitrogen, which in turn influence seedling growth. Specifically, in P. yedoensis, the relative growth rate of height was significantly higher in BIOC (46.19 ± 3.47%) compared to the control (29.58 ± 3.22%). The ameliorants did not significantly affect root morphological traits; however, we found that the total fine root length was positively correlated with shoot biomass in G. biloba (R = 0.97), but not in P. yedoensis. Root length tended to increase in BIOC, with measurements of 288.12 ± 68.97 m for P. yedoensis and 65.96 ± 25.08 m for G. biloba, while the mean fine root diameter tended to decrease in ORGF (1.25 ± 0.04 mm) and BIOC (1.37 ± 0.08 mm) for G. biloba. We conclude that biochar and organic fertilizer positively affect both soil properties and plant growth, highlighting that enhanced root development through ameliorants can improve plant growth in compacted soil.

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.

Effects of different karst fissures and rainfall distribution on the biomass, mineral nutrient elements, antioxidant substances, and photosynthesis of two coniferous seedlings

BackgroundStudying the physiological growth status of Pinus yunnanensis Franch and Pinus elliottii Engelm. seedlings under different karst fissure thicknesses and rainfall distributions is of great significance for the management, vegetation restoration, and tree species selection in karst rocky desertification areas. In this study, we used a two-factor block experiment and set different rainfall durations, namely reduced rainfall duration (I3d), natural rainfall duration (I6d), and extended rainfall duration (I9d); Different karst small habitats, i.e., stone-free soil (S0), less stone and more soil (S1/4), and half stone and half soil (S1/2), are simulated at these three levels. Analyze the changes in physiological growth and photosynthetic characteristics in two coniferous seedlings under different treatments with different karst thicknesses.ResultsThe results showed that with the increase of karst thickness, the growth volumes of height and diameter of P. yunnanensis seedlings, the biomass of various organs, and the accumulation of K+, Ca2+, Na+, and Mg2+ showed a significant change pattern of first increasing and then decreasing (P < 0.05); P. elliottii seedlings show a gradually decreasing trend (except for Ca2+). The biomass accumulation of each organ in two coniferous seedlings showed that leaves > stems > roots. The K+, Ca2+, and Mg2+ content in various organs of P. yunnanensis seedlings showed that leaves > roots > stems, while Na+ shows the order of roots > leaves > stems. The accumulation of mineral elements in various organs of P. elliottii seedlings is manifested as roots > stems > leaves and the accumulation of mineral elements in both coniferous seedlings is manifested as Ca2+ > Mg2+ > K+ > Na+. Root length, root volume, root surface area, root diameter, SOD, POD, SP, photosynthetic pigment content, fluorescence parameters, and gas exchange parameters of P. yunnanensis seedlings gradually increase with the increase of karst thickness (except for the 9-day rainfall duration), while those of P. elliottii seedlings gradually decrease. The light saturation point of P. yunnanensis seedlings is highest under the I6dS1/2 treatment, while that of P. elliottii is highest under the I3dS0 treatment.ConclusionsIn summary, prolonging rainfall duration has an inhibitory effect on the growth of two types of coniferous seedlings. Increasing karst thickness inhibits the growth of P. elliottii seedlings, and to some extent, promotes the growth and development of P. yunnanensis seedlings. I6dS1/4 and I3dS0 treatments have the best growth effects on P. yunnanensis and P. elliottii seedlings. Therefore, we give priority to P. yunnanensis as the tree species for vegetation restoration or rocky desertification management in karst areas. Our study reveals the role of limestone-filled different karst fissures in mitigating the effects of drought as “containers” for plant growth. These findings help us understand the response of plants to drought stress and provide valuable insights for vegetation restoration in karst environments affected by global climate change. Therefore, further experiments with various karst fissure sizes are necessary to test the universality of the reactions of various plants under different karst fissures.

Proline Accumulation and Drought Tolerance in Green Gram (Vigna radiata L.)

Green gram (Vigna radiata L.), a key legume crop in Asia, contributes to sustainable agriculture by fixing atmospheric nitrogen and providing valuable nutrients. Despite its importance, productivity is hindered by various factors including drought, affecting key physiological and biochemical processes, leading to reduced yields. This study aimed to identify drought-tolerant green gram genotypes by evaluating 50 accessions for root, shoot and biochemical parameters under controlled moisture stress. An increase in root length and diameter under stress was observed, which aids in nutrient uptake and osmoregulation. Conversely, shoot length and dry weight decreased due to moisture limitations, with genotypes like VBN 3 and PLM 38 showing resilience by maintaining higher dry weights. Biochemical analysis revealed that proline accumulation, which correlates positively with drought tolerance, increased in most genotypes, particularly in IC 395518 and ML 1415. This suggests its role in maintaining cell turgor and mitigating stress effects. Chlorophyll content decreased under stress, while total phenolic content increased in some genotypes, further indicating drought tolerance. Correlation and path analysis revealed strong positive relationships between root traits and proline content, emphasizing their importance in drought tolerance. The study concludes that genotypes with robust root systems and higher proline accumulation are more capable of withstanding drought, highlighting the need for breeding programs targeting these traits for improved green gram productivity under changing climates.

Structural echocardiographic parameters in male and female Asian athletes: a systematic review and meta-analysis

Abstract Introduction Following repetitive structured and intense physical training, elite athletes’ hearts undergo physiological cardiac remodelling, including increased left ventricular (LV) size and LV wall thickness. These changes may mimic those seen in pathological cardiac conditions such as dilated and hypertrophic cardiomyopathy, posing a challenge for accurate diagnosis. Reference ranges for common echocardiographic parameters in elite Caucasian and Black athletes have been reported, facilitating differentiation between physiological and pathological changes in these demographics. However, there remains a paucity of data for Asian athletes despite their increasing representation in global sport. Methods We searched MEDLINE via PubMed, Embase, and the Cochrane Database for relevant studies from inception till 20th November 2023. We included observational studies that reported relevant echocardiographic parameters in elite Asian athletes. Studies that did not report gender-specific cardiac imaging parameters were excluded. After study selection and data extraction, random-effects meta-analysis of means was performed to obtain the weighted mean and 95% confidence intervals (CI) of common echocardiographic parameters stratified by gender. Results Our final search yielded 10 studies comprising a total of 1,111 elite athletes (996 male, 115 female; 53% Japanese, 21% uncategorised, 14% South-East Asian). Athletes participating in skill and power disciplines were excluded from analysis post-hoc due to a paucity of data and extreme data ranges. In male athletes, mean LV wall thickness was 9.4 mm (95% CI 8.5-10.3, I2 = 98.9%), mean LV end diastolic diameter was 54.7 mm (95% CI 52.5-57.0, I2 = 98.6%), mean LV mass indexed to body surface area was 97.5 g/m2 (95% CI 90.5-104.5, I2 = 97.5%) and mean aortic root diameter was 31.9 mm (95% CI 29.2-34.7, I2 = 99.5%). In female athletes, mean LV wall thickness was 7.9 mm (95% CI 7.5-8.4, I2 = 85.4%), mean LV end diastolic diameter was 47.1 mm (95% CI 45.8-48.3, I2 = 77.3%), mean LV mass indexed to body surface area was 79.5 g/m2 (95% CI 69.2-89.7, I2 = 92.8%) and mean aortic root diameter was 27.5 mm (95% CI 26.9-28.1). Conclusion This meta-analysis describes commonly reported echocardiographic parameters in elite Asian athletes from endurance and mixed sport disciplines. The absolute values of all reported parameters appear to fall far below reported limits for non-Asian athletes, highlighting substantial ethnic and regional variation in cardiac remodelling in elite athletes. While our results facilitate preliminary referencing of expected normal ranges in this demographic group, further studies are necessary to fully define the cardiac characteristics of Asian athletes.

Sex differences in aortic prognosis in Marfan patients, a retrospective longitudinal study from the REPAG registry

Abstract Introduction Previous studies(1-4) have suggested a more favourable aortic outcome among women with Marfan syndrome (MFS), although the precise underlying mechanism remains not completely understood. In this retrospective longitudinal study, we aim to evaluate sex differences in aortic events in a large cohort of Marfan patients seen in 11 tertiary centres in Spain. Methods Patients with diagnosis of Marfan syndrome (MFS) were included. Data on aortic events (AE) including elective aortic surgeries, acute aortic syndrome or death were incorporated. Survival free of the combined endpoint of death or first aortic event (elective aortic surgery or acute aortic syndrome) was compared between male and female by the Kaplan-Meier curves, log-rank test and subsequent Cox regression analysis. Results A total of 442 patients with MFS where included, 48.2% female and 56.2% index cases. Although systemic score and proband proportion was not different between both sexes, the diagnosis was earlier in males (p=0.01) (Table). Furthermore, among adult patients, males exhibited greater height, weight, and body surface area (BSA). Absolute aortic root diameter at baseline was greater in males, but not BSA-indexed diameters or z-scores. Combined endpoint of death or aortic event was observed in 192 patients (120 male, 72 female, p=&amp;lt;0.00001). Female sex had better survival free of the combined endpoint in a multivariable Cox analysis (HR 0.41 95% CI=0.30–0.55) with a mean survival free of the combined endpoint of 41.3yrs in male and 61.4 years in females (p&amp;lt;0.0001) (Figure).Although a higher proportion of elective aortic interventions as first event was observed in males (66.7% vs 52.8%), the proportion of type A dissections was similar between both sexes (26.7 vs 26.4%) with increased frequency of type B dissections in females as first aortic event (4.2 vs 15.3%) (p=0.026) Conclusions Male patients with MFS present higher aortic root diameters but similar BSA-indexed and zscores than females. Survival free of first aortic event or death is reduced in male with MFS, with greater frequency of elective aortic intervention. Although this last is driven by absolute aortic diameter, no increase on type A dissection was observed in women. These findings might suggest a potentially less aggressive manifestation of proximal aortic disease in women with MFS.Table:Comparison male and female Marfan

Anatomical classification of patent foramen ovale before percutaneous closure

Abstract Introduction Anatomical characteristics of patent foramen ovale (PFO) vary a lot, potentially impacting the embolic risk, selection of the device and the final sealing results of the closure procedure. Objective To categorize the different PFO anatomies and evaluate the consequence on the type of device used and the incidence of residual shunt. Methods 624 consecutive patients who underwent PFO percutaneous closure with transoesophageal echocardiography (TEE) guidance were retrospectively reviewed. Four types of PFO were identified once a rigid wire was in place using per-procedural TEE. This new classification was based on the PFO sheathed tunnel’s length and width, presence of concomitant atrial septal aneurysm (ASA) or additional defect (ASD), width of the septum secundum (SS) and aortic enlargement (Figure 1). Type I, or "single PFO" was defined by the absence of ASA or ASD, a tunnel width ≤ 4mm, SS’s width ≤ 10mm and no aortic enlargement (i.e., aortic root diameter &amp;lt;21mm/m², distorted anatomy or scoliosis). Type II or "dominant septal aneurysm" was defined by the presence of an ASA, with a distinction between subtype IIa (long PFO tunnel with length ≥10mm) and subtype IIb (short PFO tunnel with length &amp;lt;10mm). Type III or "modified PFO" was defined by SS’s width &amp;gt; 10 mm, aortic enlargement, or severe scoliosis, and type IV or "multi perforated" was defined by the presence of a concomitant ASD or a multifenestrated septal wall. In case of concomitant criteria, the predominant order was IV, then IIb, then III. For each category, the presence of residual shunt was evaluated after Valsalva manoeuvres with contrast echocardiogram 6 months after the procedure. Results Our population had a median age of 51 [41-59] years and included 43.8% women. The type II PFO was the most frequently encountered, with 42% of the patients (Table 1). A total of 44 (7.1%) patients presented multiple types concomitantly (mostly type II and III). PFO occluders were the most implanted devices overall, particularly with type I and IIb, while ASD occluder were more frequently used with types IV and IIb. Cribriform/Uni™ devices were more frequently used with type IV. Large devices (i.e., left disc’s diameter &amp;gt;25 mm) were predominantly used with type III and IV, but scarcely employed with type I and II. Within type II anatomies, large devices were significantly more frequently used with type IIb. Fluoroscopy duration was significantly higher with type IV. At 6 months ultrasound evaluation, large right-to-left residual shunt was significantly more frequent with type IV anatomy and with patients presenting multiple types concomitantly (18/34 - 40.9%). No significant differences were observed regarding clinical outcomes during follow-up. Conclusion Based on specific anatomical characteristics, four types of PFO may be identified, presenting with increasing procedural complexity, and requesting specific closure devices.

Soil Physical Properties, Root Distribution, and “Ponkan” Tangerine Yield Across Different Rootstocks in a Deep Tillage Ultisol

Deep soil tillage and proper rootstock selection mitigate the root development limitations in Ultisol’s Bt horizon, enhancing the citrus yield potential. This study evaluates the root spatial distribution of three Ponkan tangerine rootstocks in Ultisol under deep tillage alongside the physical-hydric attributes and plant measurements. The experimental area underwent furrow creation, subsoiling, and hole opening for planting. The treatments included three rootstocks: “Cravo Santa Cruz” (CSC), “Sunki Tropical” (ST), and “Citrandarin Índio” (CI). Under the Ultisol preparation, these rootstocks were compared to a native forest area (FA). Three years post-initial tillage, soil samples were collected at depths of 0–0.05, 0.35–0.40, and 0.45–0.50 m from the pre-established positions. The evaluation encompassed soil dispersive clay, available water, crop water use, plant measurement, and crop yield. The root evaluation utilized the crop profile method and 2D images, with subsequent surface mapping of the root variables, number (NR), and diameter (RD) analyzed via kriging geostatistical analysis. The Ultisol showed significant changes in its physical-hydric attributes regarding structural change and more excellent clay dispersion, with a considerable contribution to the micropore volume. Deep tillage effectively improved the root spatial distribution, especially concerning the number and diameter of roots, and enhanced the water use, reflected in the vegetative growth and yield, with the rootstock CSC standing out.

Short-Term Effects of Incorporation Depth of Straw Combined with Manure During the Fallow Season on Maize Production, Water Efficiency, and Nutrient Utilization in Rainfed Regions

Diminishing soil fertility and crop productivity due to traditional intensive cultivation has prompted the use of straw and manure to improve soil health in Northeast China. However, few comparative studies have explored the influence of varying straw and manure incorporation depths on crop growth. A field experiment in the rainfed black soil regions of Gongzhuling and Keshan assessed the effects of deep (30 cm) and shallow (15 cm) incorporations of straw and manure on soil fertility, maize root growth, and maize productivity. Deep incorporations, via subsoiling tillage (DST) and deep-plow (DDT) tillage, enhanced soil water storage of 30–100 cm soil layer during periods of low rainfall, improved the availability of nutrients (nitrogen, phosphorus, and potassium) and soil organic matter content, especially in deeper soil, compared to shallow incorporation using rotary tillage (SRT). Both DST and DDT induced a larger rooting depth and a higher fine root (diameter class 0–0.5 mm) length density by 31.0% and 28.9%, respectively, accompanied by reduced root turnover. Furthermore, the sub-surface foraging strategies of roots under the DST and DDT treatments boosted the total nitrogen, phosphorus, and potassium uptake (6.5–17.9%) and achieved a higher dry mass accumulation during the later growth period, thus leading to notable improvements in the 100-kernel weight and yield (16.1–19.7%) and enhancing water- and nutrient-use efficiencies by 2.5–20.5%. Overall, compared to shallow incorporation, deep incorporation of straw and manure significantly enhances root growth and spatial distribution of soil water and nutrients, which has great potential for increasing maize yield in rainfed agricultural areas.

Association mapping unravels the genetic basis for drought related traits in different developmental stages of barley

Drought stress significantly reduces crop yields at all stages of plant development. Barley, known for its abiotic-stress adaptation among cereals was used to examine the genetic basis of drought tolerance. A population of 164 spring barley lines was subjected to polyethylene glycol (PEG) induced drought stress during germination and seedling development. Six traits were measured, including germination percentage and rate, seedling length and weight, and root-to-shoot ratios. Seedling area, volume, and root and shoot diameter was acquired with a flatbed scanner. This population was also subjected to short-term drought during the heading stage in the greenhouse. Root and shoot weight and grain yield data were collected from well watered and droughted plants. Significant variation within traits were observed and several of them exhibited strong correlations with each other. In this population, two genotypes had 100% germination under PEG-induced drought and drought tolerance throughout the heading stage of plant development. A genome-wide association scan (GWAS) revealed 64 significant marker-trait associations across all seven barley chromosomes. Candidate genes related to abiotic stress and germination were identified within a 0.5Mbp interval around these SNPs. In silico analysis indicated a high frequency of differential expression of the candidate genes in response to stress. This study enabled identification of barley lines useful for drought tolerance breeding and pinpointed candidate genes for enhancing drought resiliency in barley.

Study on Shear Strength of Soil–Root Systems of Different Vegetation Types

The root systems of vegetation significantly contribute to enhancing slope stability. The shear strength of soil–root systems is a crucial parameter for assessing slope stability. This study focuses on six types of vegetation in the Yellow River Basin of China (woodland: Populus przewalskii and Broussonetia papyrifera; shrubland: Periploca sepium and Ziziphus jujuba; grassland: Artemisia hedinii and Setaria viridis), employing in situ shear tests and the Wu–Waldron model (Wu model) to investigate the shear strength of soil–root systems. The results show that the shear stress–displacement curves for P. przewalskii, B. papyrifera, and Z. jujuba are higher and steeper, with clear inflection points. The tensile strength of the roots from the six vegetation types decreases as the root diameter increases. According to the Wu model, the additional root cohesion is ranked as follows: A. hedinii &gt; B. papyrifera &gt; P. przewalskii &gt; Z. jujuba &gt; P. sepium &gt; S. viridis. Based on the in situ shear tests, the shear strength increments are ranked as follows: Z. jujuba &gt; B. papyrifera &gt; P. przewalskii &gt; A. hedinii &gt; P. sepium &gt; S. viridis. Overall, the additional root cohesion obtained by the Wu model in each soil layer is greater than the shear strength increment measured from the in situ shear tests. In the 0–30 cm soil layers, the soil–root systems of Z. jujuba, B. papyrifera, P. przewalskii, and A. hedinii exhibit a better shear strength, whereas P. sepium and S. viridis perform poorly. A principal component analysis reveals that the shear strength of the soil–root systems of different vegetation types is primarily influenced by the soil moisture content and root mass density. Z. jujuba, B. papyrifera, P. przewalskii, and A. hedinii are recommended for ecological restoration projects in the Yellow River Basin of China.

Mitigation strategy of saline stress in Fragaria vesca using natural and synthetic brassinosteroids as biostimulants.

Bassinosteroids (BRs) can induce plant defence responses and promote plant growth. In this work, we evaluated the effect of a natural (EP24) and a synthetic (BB16) brassinosteroid on strawberry (Fragaria vesca ) plants exposed to saline stress. Treated plants showed higher shoot dry weight and root growth compared to untreated control plants. In BR-treated plants, crown diameters increased 66% and 40%, leaf area 148% and 112%, relative water content in leaves 84% and 61%, and SPAD values 24% and 26%, in response to BB16 and EP24, respectively. A marked stomatal closure, increased leaflet lignification, and a decrease in cortex thickness, root diameter and stele radius were also observed in treated plants. Treatments also reduces stress-induced damage, as plants showed a 34% decrease in malondialdehyde content and a lower proline content compared to control plants. A 22% and 15% increase in ascorbate peroxidase and total phenolic compound activities was observed in response to BB16, and a 24% increase in total flavonoid compound in response to both BRs, under stress conditions. These results allow us to propose the use of BRs as an environmentally safe crop management strategy to overcome salinity situations that severely affect crop yield.

Relationship between root system-soil C:N:P and soil microbial diversity at different evolutionary stages of Caragana tibetica scrub in arid desert grassland, Northern China.

Scrub root systems play a crucial role in preventing soil erosion and nutrient loss. However, the effects of the root system configuration on soil nutrient dynamics and microbial changes at various evolutionary stages remain poorly understood. In this study, we investigated the relationship between soil physical and chemical properties and the diversity of bacteria and fungi throughout the evolutionary stages of the scrub root systems. This was achieved through a combination of whole-root excavation and root tracing techniques. The results indicated that root diameter was the main factor contributing to the continuous increase in carbon (C): phosphorus (P) and nitrogen (N): P ratios as the scrub sand pile developed. The soil organic carbon (SOC), total soil nitrogen (TN), and total soil phosphorus (TP) contents in the soil in the four evolutionary stages were the highest during the developmental stage, but the change in TP content was not statistically significant (P > 0.05). Partial least squares path modeling and redundancy analysis (RDA) indicated that root system stoichiometric C and N contents were positively correlated with microbial diversity (R2 = 0.85). There was no correlation between the evolutionary stage and soil nutrient TN, whereas soil nutrient TN was negatively correlated with microbial diversity (R2 = -0.92). These findings elucidate the relationship between the evolutionary stage of root chemical measurement characteristics, soil elements and microorganisms, and their subsequent effects on root elemental composition and microbial diversity. This study enhances the current understanding of plant-soil interactions in desert steppe ecosystems.

Root traits of soybeans exposed to polyethylene films, polypropylene fragments, and biosolids

Biosolid use imports microplastics into the rhizosphere where they may interfere with root-soil-microbial interactions and cause morphological adaptations in crop root systems. Few studies have examined the response of crop roots to microplastics at documented soil concentrations, and many studies collect root traits using destructive techniques. Hence, there is little information on when and how microplastics effect the physical structure of root systems. Using the rhizobox method, soybeans (Glycine max) were grown in soil amended with biosolid microplastic mimics (polyethylene film or polypropylene fragments at 2,000 and 15,000 particles/kg dry soil) or biosolids and imaged weekly until maturity (11 weeks) using a custom scanner system. Plant biomass increased in the polyethylene treatments and decreased in the high concentration polypropylene treatment. Relative to the Control, polyethylene treatments had larger root length, reduced root diameters, reached maturity faster, had deeper root systems, and had a greater number of lateral roots. In contrast, polypropylene treatments had a mixed response, with high concentrations eliciting a lower root length, fewer laterals, and a more vertical root orientation. Segmented linear regression revealed that root growth in the Control and Biosolid treatments continued through the course of the experiment, while the microplastic treatments reached maturity up to two weeks earlier. Imagery revealed that microplastics elicited deeper rooting depth within the first week and differences in all root traits were evident by the development of the first trifoliate leaflets. Microplastic effects on root traits at early life stages suggest soil physiological drivers, while increased branching frequency and lower lateral elongation are suggestive of changes in soil nitrogen availability. The minimal difference in root traits in the biosolid treatment may be attributable to differences in microplastic properties or counteractive effects by other biosolid constituents.

Soil density specification ranges to optimise plant water use and root growth for phytocapping and urban greening projects

Soil density or compaction is one of the key variables that need to be specified for designed soil profiles as part of urban greening. Examples include land rehabilitation (mining), waste containment (phytocapping), stormwater infrastructure (bioretention basins) and green infrastructure (green roofs and street trees). This study investigates the impact of a range of specified soil densities on plant water use and root development. Native Australian plant species selected for the study include: the C4 and C3 grasses, Themeda triandra and Microlaena stipoides respectively; the Eucalyptus trees, E. camaldulensis and E. cladocalyx; and the nitrogen-fixing pioneer trees, Acacia mearnsii and Allocasuarina verticillata. The plants were established at four soil density (compaction) levels: 72, 77, 82, and 87 % MDD (maximum dry density) in tall cylinders with weekly plant water use measurement over 8 months. Root growth was analysed using WinRhizo image analysis. The experimental results were used to create generalisable models for root length density (RLD), root diameter and plant water use. The models for RLD and plant water use were parabolic in nature, revealing clear optimum ranges that could be used to guide soil density specification. Root diameter provided additional insight into the allocation of resources to root thickening above a threshold soil density of 87 % MDD, indicating plant allocation of resources towards penetrating highly compacted soils. There were correlations between plant water use and RLD that were moderate and significant, particularly for grasses. Notably, T. triandra had the greatest mean RLD, thickest roots and plant water use at 16.8cm/cm3, 0.18 mm and 10mm/week, respectively. Findings demonstrate that RLD and plant water use can be optimised together within practically achievable soil density specification ranges that are sensitive to the pitfalls of both excessively low and excessively high soil densities. Recommended soil density specification ranges include: 75–82 % MDD with plant performance within 5 % of optimum (considered excellent), 74–84 % MDD with plant performance within 10 % of optimum (considered good) and 73–85 % MDD with plant performance within 15 % of optimum (considered fair). Within these ranges, plant water use and root growth performance is well balanced with practical achievement of the soil density ranges. Due to the use of %MDD, the modelled results can be usefully generalised for any soil type. Implementation of these specifications for urban greening and phytocap projects will optimise plant growth, transpiration and hydrological function while maintaining root networks essential for establishing and maintaining resilient living infrastructure.

Effect of Organic and Inorganic Fertilizers on Growth, Yield and Quality of Radish (Raphanus sativus L.) cv. Pusa Himani

In this report, we compared the integrated effect of FYM, vermicompost, poultry manure with inorganic fertilizers incorporated with PSB for yield in radish cv. Pusa Himani in response of morphological, yield as well as quality attributes. As per data analysis T6 [NPK (75%) + vermicompost (25% of N) + PSB] significantly enhanced the highest plant height, leaf length, number of leaves per plant, fresh weight of shoot and dry weight of shoot at 20 DAS, 40 DAS and at harvest, respectively. Similarly, at harvest maximum root length, maximum root diameter, maximum average weight of root, maximum yield per hectare, minimum days to harvest and quality parameters i.e. T.S.S., ascorbic acid, chlorophyll content of leaves, net return and B-C ratio in comparison to all concentration with all integrated nutrient combination. So, we may conclude that [NPK (75%) + vermicompost (25% of N) + PSB] increase yield by stimulating source activity as well improves utilization of PGR (plant growth regulators).

Effects of cinnamic acid on the root growth of cucumber (cucumis sativus l.) and figleaf ground (cucurbita ficifolia bouché) seedlings

Effect of cinnamic acid (CA) on growth and endogenous hormone content in the roots of cucumber and figleaf gourd seedlings were studied and explained the reason why figleaf gourd was better in resisting CA stress than cucumber using their seedlings as experimental materials. The effect of CA at different concentrations (0, 0.05, 0.10, 0.15, 0.20 and 0.25 mmol/l) was analysed on primary root elongation, total root elongation, average diameter of total roots, total root volume, and total root tips as well as the effects of 0 and 0.25 mmol/l CA on root growth, root density, root hair growth rate, indole acetic acid (IAA) content and ethylene (ET) production rate. The results showed that CA stress decreased the primary root elongation, total root elongation, total root tips, Grade III root and root hair growth rates of both plants. The inhibiting effect of CA was stronger on cucumber than figleaf gourd. Besides, CA stress increased their average diameters of total roots and root hair densities. The increase in the average diameter of total roots of cucumber was larger than that of figleaf gourd while its increase in root hair density was far lower. Apart from that, 0.25 mmol/l CA stress increased the IAA contents and ET production rates in both kinds of roots. The increase in IAA content in cucumber root was 16% higher than in figleaf gourd. However, the increase in the ET production rate of cucumber root was 51% lower than figleaf gourd root. In conclusion, higher concentration IAA could inhibit root growth. Under CA stress, the increase in the IAA content in figleaf gourd root was lower than that in cucumber root, indicating that CA exerted a weaker inhibiting influence on figleaf gourd. Besides, higher ET production rate contributed to the increase in root hair density. Under CA stress, figleaf gourd root had a higher ET production rate than cucumber root, thus having more root hairs. Bangladesh J. Bot. 53(3): 703-710, 2024 (September) Special

Role of total polyphenol content in seed germination characteristics of spring barley varieties amidst climate change

The amount of total polyphenol content (TPC) in the grain could provide insights into the conditions during maturation and might also serve as an indicator of the grain’s ability to germinate in the malting process or as seeds in the field. Varieties with higher natural TPC content might exhibit better germination parameters both in the field and in the malt house. This study investigates the relationship between TPC and seed germination characteristics i.e. seed vigour in four spring barley varieties over two years, considering diverse environmental conditions and exposure to drought conditions. The evaluation of seed germination characteristics in barley, with a focus on the root length and average diameter under drought conditions (−0.5 MPa) and suboptimal temperature (10 °C), was conducted. Drought conditions were induced using polyethylene glycol (PEG 6000). After durations of seven and fourteen days, the germinated seeds from the Petri dishes were scanned and subjected to analysis using WinRHIZO software following the metrics: Len 7, Len 14 (root length after seven and fourteen days in cm) and AvgD 7, AvgD 14 (root diameter after seven and fourteen days in mm). The findings support our initial hypothesis, indicating a variety-specific relationship between seed germination characteristics and increased TPC, where higher germination parameters might be associated with elevated TPC levels in some barley varieties.

Traits associated with the conservation gradient are the strongest predictors of early‐stage fine root decomposition rates

Abstract Fine root traits span two independent axes of variation, the conservation and collaboration axes, which define the root economic space (RES). However, whether early‐stage fine root decomposition rates (quantified as proportion mass loss, i.e. pml) are more strongly related to collaboration or conservation traits remains unclear. We studied 63 tree species in New Zealand's temperate rain forest. We determined the phylogenetic signal in pml and fine root traits, conducted phylogenetic principal component analysis and used phylogenetic generalized least squares to determine which traits are most strongly related to pml. Root decomposition exhibited a high phylogenetic signal and was more strongly related to the conservation than the collaboration axis. Root tissue density (RTD) was negatively correlated and root nitrogen (RN) was positively correlated with pml. Root diameter was positively yet weakly correlated with pml, but specific root length was uncorrelated with pml. The lignin‐to‐N ratio and root cellulose were the strongest predictors of pml. Synthesis: Early‐stage fine root decomposition is most strongly driven by tissue quality traits, such as root nitrogen, tissue density and lignin‐to‐N ratio, which all align with the conservation axis of the root economics space. However, root diameter plays a weak yet undeniable role in early‐stage fine root decomposition. Some thick‐rooted species decomposed faster, possibly due to the higher quality cortical tissue. Thin‐rooted species decomposed slower, possibly because of their higher cellulose concentration that maintains the structural integrity of small diameter roots. Relationships between decomposition and other traits that align with the collaboration gradient deserve further study across the phylogeny of vascular plants.

Sodium alginate-g-polyacrylamide hydrogel for water retention and plant growth promotion in water-deficient soils

Natural polymer-based hydrogels are preferred as soil water retention agents due to their inherent biocompatibility and biodegradability. Generally, these natural polymers are chemically modified by graft polymerization of vinyl monomers to improve their water absorption and retention properties. Among the polysaccharides used to prepare natural hydrogels, those based on sodium alginate (Alg) stand out for their high-water absorption and retention capacity, as well as for their ability to promote plant growth. The main objective of this study was to develop a biodegradable alginate-based hydrogel as a water retainer to promote plant growth under water deficit conditions. The synthesis was achieved by grafting poly(acrylamide) (PAM) onto Alg backbone, using bisacrylamide as chemical crosslinker and different ratios of alginate:acrylamide (Ac). In addition, Eucalyptus nitens seedlings were used as a model plant to evaluate the effect of alginate-g-polyacrylamide (Alg:PAM) hydrogel application to the growing medium on plant survival, growth, and physiological responses under both well-watered and water-deficient soil conditions. The maximum degree of swelling (65 g/g) was obtained for the hydrogel prepared. The pseudo-second order model described the water uptake kinetics of the hydrogel. The degradability of Alg:PAM hydrogel reached up to 85 % in 5 weeks in soil and occurs by breaking the glycosidic bonds of the alginate. The E. nitens seedlings cultivated with different doses of Alg:PAM hydrogel (4:1 Alg:Ac) showed higher values of height and root diameter relative growth, survival and photosynthetic responses in comparison to non-treated plants. The results indicate that Alg:PAM hydrogel (4:1 Alg:Ac) has promising applications in forestry as a water retention and seedling growth promoter under water deficient conditions.