Roots Of Woody Plants Research Articles

Does succulence in woody plants delay desiccation, and is stored water used to maintain physiological function during drought conditions?

Succulence is a trait that describes water storage in plant organs and tissues regardless of life form. Plants use the stored water to maintain physiological function and delay desiccation. However, it is unclear whether succulence in leaves, stems and roots of woody plants delays desiccation, whether it provides 'utilizable water' to maintain physiological function, or buffers changes in water status in drying soils through capacitance. We conducted a pot dry-down experiment with nine shrub species to determine whether woody plants with greater leaf, stem, or root succulence have greater shoot utilizable water or capacitance. We also investigated whether greater succulence delays desiccation, represented by cumulative VPD, until evapotranspiration ceased or until utilizable water was exhausted. Greater leaf and stem succulence were strongly related to greater shoot utilizable water and capacitance. However, desiccation time was not delayed in plants with greater total shoot succulence, utilizable water, or capacitance. Instead, woody plants with greater root succulence had longer desiccation times. This suggests that woody plants use aboveground succulence to maintain physiological function and water status during drought, whereas root succulence extends desiccation time. Our study improves the mechanistic understanding of how woody plants use stored water to survive in dryland ecosystems.

Divergent responses of woody plant leaf and root non-structural carbohydrates to nitrogen addition in China: Seasonal variations and ecological implications

Plant non-structural carbohydrates (NSCs), which largely comprise starch and soluble sugars, are essential energy reserves to support plant growth and physiological functions. While it is known that increasing global deposition of nitrogen (N) affects plant concentration of NSCs, quantification of seasonal responses and drivers of woody species leaf and root NSCs to N addition at larger spatial scales remains lacking. Here, we systematically analyzed data from 53 field experiments distributed across China, comprising 1202 observations, to test for effects of N addition on woody plant leaf and root NSCs across and within growing and non-growing seasons. We found (1) no overall effects of N addition on the concentrations of leaf and root NSCs, soluble sugars or starch during the growing season or the non-growing season for leaves. However, N addition decreased root NSC and starch concentrations by 13.8 % and 39.0 %, respectively, and increased soluble sugars concentration by 15.0 % during the non-growing season. (2) Shifts in leaf NSC concentration under N addition were driven by responses by soluble sugars in both seasons, while shifts in root NSC were driven by soluble sugars in the non-growing season and starch and soluble sugars in the growing season. (3) Relationships between N, carbon, and phosphorus stoichiometry with leaf and root NSCs indicated effects of N addition on woody plant NSCs allocation through impacts on plant photosynthesis, respiration, and growth. (4) Effects of N addition on leaf and root NSCs varied with plant functional types, where effects were more pronounced in roots than in leaves during the non-growing season. Overall, our results reveal divergent responses of woody plant leaf and root NSCs to N addition within non-growing season and highlight the role of ecological stoichiometry and plant functional types in woody plant allocation patterns of NSCs in response to ongoing N deposition under global change.

Fast, Easy, and Comprehensive Techniques for Microscopic Observations of Fungal and Oomycete Organisms Inside the Roots of Herbaceous and Woody Plants.

The roots of herbaceous and woody plants growing in soil are complex structures that are affected by both natural and artificial fungal colonization to various extents. To obtain comprehensive information about the overall distribution of fungi or oomycetes inside a plant root system, rapid, effective, and reliable screening methods are required. To observe both fine roots, i.e., a common site for penetration of fungi and oomycetes, and mature roots, different techniques are required to overcome visual barriers, such as root browning or tissue thickening. In our protocol, we propose using fast, cost-effective, and non-harmful methods to localize fungal or oomycete structures inside plant roots. Root staining with a fluorescent dye provides a quick initial indication of the presence of fungal structures on the root surfaces. The protocol is followed by clearing and staining steps, resulting in a deeper insight into the root tissue positioning, abundance, and characteristic morphological/reproductive features of fungal or oomycete organisms. If required, the stained samples can be prepared by using freeze-drying for further observations, including advanced microscopic techniques. Key features • The protocol enhances tissue-clearing techniques employing KOH or NaOH and is applicable to a broad range of roots from different plant species. • Hydroxides are mixed with hydrogen peroxide to obtain an efficient bleaching solution, which effectively clears roots without causing significant tissue damage. • The protocol could also be used for staining of fungi or oomycetes localized both on the root surface or inside the root tissues. • Simple combination of non-fluorescent methyl blue and fluorescent solophenyl flavine dyes allows the observation of fungal organisms in both brightfield and fluorescence microscopy.

Vegetation at the former open-pit Ningyo-toge mine, 36 years after closure treatment: Impact of soil cover on woody plant establishment and dominance of the perennial herb Miscanthus sinensis

Soil cover is a prevailing method used at mine sites to ensure the safety of hazardous materials and restore ecological functions when the base materials are unfavorable for plant growth. The former open-pit Ningyo-toge Mine was backfilled with overburden and neutralized smelting residues and covered with soil in 1987. After 36 years, the vegetation remained dominated by the perennial herb Miscanthus sinensis, and woody plant establishment did not progress successfully. This study investigated the factors that inhibited woody plant establishment at the site. The soil profile survey revealed that the soil cover formed Bg horizons (pseudogley soil) with cloudy mottling, representative of poorly drained soil. In the Bg horizon, woody plant roots of Pinus densiflora and Weigela hortensis exhibited growth inhibition. Elemental analysis revealed that in the Bg horizon the roots of P. densiflora and W. hortensis accumulated high Fe concentrations exceeding 10,000 mg/kg DW at critical levels. Our results suggested that woody plant roots in the Bg horizon may have suffered from chronic oxygen deficiency accompanied by excessive Fe stress in the soil cover. Topsoil water content (<50 mm) and microtopographic features were not critical factors disrupting woody plant establishment because some individuals were growing in areas with high soil water content, exceeding 60%. Considering that woody plant roots were developed primarily in the shallow A horizon, A horizon formation by M. sinensis is a key step in initiating woody plant establishment by improving the soil structure and physiochemical characteristics of the soil cover, such as carbon content, exchangeable nutrients, and air-filled porosity. For successful mine pollution control and vegetation recovery, implementing an appropriate topsoil system, such as native forest soil, loosely graded and minor infiltration layer above the overburden would be necessary.

Texture Inspection using the Voice Based Biometric Authentication in the Quantum Computation

Texture inspection has remained an important substance throughout the whole history because with the advances of the mobile graphics and many hardware, high-quality image processing for the basic wood texture in the Wolfram mathematical. We also used wood in the building material and household furniture to find out the type of wood that can be used as a specific material and to help in the development of the different wood texture in the android studio. Cedar is a fibrous and a porous structural tissue found in the roots of trees and other woody plants. The colour of the wood has been depend on the reflection of the most important component of the wood grain may be the process of refining or protection of the wooden surface in the production of the manufacturing cost 5 and 30%. Various Woods textures having the appearance of the wood that require the wood joints for the great variation between sapwood and heartwood.

Fine-root morphology of woody and herbaceous plants responds differently to altered precipitation: A meta-analysis

The growth of plant roots and their acquisition of resources are significantly impacted by changes in precipitation patterns. Although numerous studies have examined the impact of precipitation on fine root systems, the rooting strategies of woody and herbaceous plants under different precipitation patterns remain to be comparatively evaluated. Accordingly, in the current study, we conducted a meta-analysis of 64 peer-reviewed articles to explore the response of 17 biomass and fine-root traits of woody and herbaceous plants to precipitation changes. Our findings demonstrate that woody and herbaceous plants have developed different root strategies to cope with altered precipitation. Specifically, when precipitation increased, the fine roots of woody plants had a larger surface area and significantly increased shallow root growth. In contrast, the fine-root morphological traits of herbaceous plants showed a stronger response to increased precipitation, in which fine-root length, volume, and tissue density increased. This may result in more effective use of available water by herbaceous than woody plants. When precipitation decreased, woody plants displayed more active fine-root morphological alterations, presenting a conservative fine-root phenotype of resource acquisition, with lower specific root length and higher fine-root tissue density. Moreover, woody plants transfer absorptive fine-root structures to deep soil layers, whereas herbaceous plants are less drought-tolerant. Furthermore, woody plants may allocate biomass more optimally than herbaceous plants in precipitation-reduction scenarios. Increased precipitation may boost soil carbon sequestration and stability in woody plant-dominated forest ecosystems under future climate change scenarios, while drought may considerably reduce soil carbon storage in grassland ecosystems. In more arid environments, where woody and herbaceous plants coexist, drought may lead to the expansion of woody plants and subsequent predominance of woody plants vegetation change. our findings will fill knowledge gaps in the literature regarding the effects of precipitation changes on the fine-root dynamics of various functional plants and will improve predictions of the vegetation dynamics of forests, grasslands, and other ecosystems vegetation dynamics under changing precipitation patterns.

The influence of anthropogenic trampling of gray forest soils on their physical properties

Abstract The purpose of the study was to determine quantitative and relative indicators that significantly affect the physical properties of gray forest soils within the park ecological trail, to show changes in the compacted soil during natural recovery. Physical properties were determined in 3-fold repetition with the help of three-dimensional cylinders, followed by the calculation of their density and porosity. Population of physiologically active roots of the upper 0.5-meter layer of gray forest soils was determined by the monolith method in 5-fold repetition. It was found out that under the influence of anthropogenic trampling, the greatest degradation changes of the studied physical indicators are manifested in the upper 10-centimeter layer of gray forest soils. An increase in the density by 32.1–38.0% and solids content of the soil by 14.1–22.8%, as well as a decrease in the volume of pores by 32.0–44.3% was recorded and mass of physiologically active roots of woody plants by 84.6–91.2%. The natural restoration of soil occurs most intensively in the upper 5-cm layer. At the same time, over a 15-year period, the following changes were observed – a decrease in density by 19.5%, the content of solid particles by 9.9%, an increase in the content of pores by 39.1% and physiologically active roots woody plants by 330.0%. Quantitative and relative indicators of their physical properties obtained for anthropogenically compacted gray forest soils explain the changes in the mass of physiologically active roots of deciduous woody plants that grow in the centers with anthropogenically compacted soils.

Isolation of cadmium-resistance and siderophore-producing endophytic bacteria and their potential use for soil cadmium remediation

Endophyte-assisted phytoremediation is an emerging technique for soil heavy metals (HMs) remediation and has become a research focus in the world because of the benefits of endophytes on plant growth and uptake of HMs. In this study, multifunctional endophytic bacteria strains were isolated and screened, and the feasibility of these strains for soil cadmium (Cd) remediation was investigated by soil incubation experiments and pot experiments. All endophytic bacteria were isolated from the roots of woody plants grown on Cd-contaminated soil. Seven endophytic bacteria strains had capacities to tolerate Cd toxicity and produce siderophores, and sequence analysis of the 16S rRNA gene classified these strains as belonging to the genera Burkholderia, Pseudomonas, Pantoea, and Herbaspirillum. All strains were able to produce hydroxamate siderophores (32.40%–91.49%) and had three or more plant growth promoting properties such as phosphorus solubilization, nitrogen fixation, indole acetic acid and 1-aminocyclopropane-1-carboxylate deaminase production. They were all strongly resistant to Cd2+ toxicity, with the minimum inhibitory concentration in LB medium ranging from 1.5 mM to 9.0 mM. Except for strain Burkholderia contaminans JLS17, other strains showed decreasing removal rates within continuously elevated Cd2+ concentration of 10–100 mg L−1. Compared with the uninoculated treatment, the inoculation of strains B.contaminans JLS17, Pseudomonas lurida JLS32, and Pantoea endophytica JLS50 effectively increased the concentration of acid-soluble Cd and decreased the concentration of reducible, oxidizable, and residual Cd in the soils of different Cd contamination levels. In pot experiments, inoculation of strains JLS17 and YTG72 significantly (p < 0.05) promoted the growth of above-ground parts and root system of slash pine (Pinus elliottii) under Cd stress. This study provides a valuable biological resource for endophyte-assisted phytoremediation and a theoretical basis for the application of endophytic bacteria for remediation of Cd-contaminated soil.

Overexpression of the HcPT1.1 transporter in Hebeloma cylindrosporum alters the phosphorus accumulation of Pinus pinaster and the distribution of HcPT2 in ectomycorrhizae.

Ectomycorrhizal (ECM) fungi are associated with the roots of woody plants in temperate and boreal forests and help them to acquire water and nutrients, particularly phosphorus (P). However, the molecular mechanisms responsible for the transfer of P from the fungus to the plant in ectomycorrhizae are still poorly understood. In the model association between the ECM fungus Hebeloma cylindrosporum and its host plant Pinus pinaster, we have shown that the fungus, which possesses three H+:Pi symporters (HcPT1.1, HcPT1.2 and HcPT2), expresses mainly HcPT1.1 and HcPT2 in the extraradical and intraradical hyphae of ectomycorrhizae to transport P from the soil to colonized roots. The present study focuses on the role of the HcPT1.1 protein in plant P nutrition, in function of P availability. We artificially overexpressed this P transporter by fungal Agrotransformation and investigated the effect of the different lines, wild-type and transformed ones, on plant P accumulation, the distribution of HcPT1.1 and HcPT2 proteins in ectomycorrhizae by immunolocalization, and 32P efflux in an experimental system mimicking intraradical hyphae. Surprisingly, we showed that plants interacting with transgenic fungal lines overexpressing HcPT1.1 did not accumulate more P in their shoots than plants colonized with the control ones. Although the overexpression of HcPT1.1 did not affect the expression levels of the other two P transporters in pure cultures, it induced a strong reduction in HcPT2 proteins in ectomycorrhizae, particularly in intraradical hyphae, but still improved the P status of host plant shoots compared with non-mycorrhizal plants. Finally, 32P efflux from hyphae was higher in lines overexpressing HcPT1.1 than in the control ones. These results suggest that a tight regulation and/or a functional redundancy between the H+:Pi symporters of H. cylindrosporum might exist to ensure a sustainable P delivery to P. pinaster roots.

Proteomic reconfigurations underlying physiological alterations in poplar roots in acclimation to changing nitrogen availability

Although the roots of woody plants are essential for nitrogen (N) uptake and assimilation, proteomic regulation underlying these processes is unclear in acclimation to changing N availability. Here, we carried out physiological and proteomic assays in Populus × canescens sapling roots treated with one of low, normal and high levels of NH4NO3. N deficiency induced lower concentrations of NH4+, total N, amino acids, inhibited enzymatic activities of nitrate reductase and glutamate synthase, decreased levels of abscisic acid and salicylic acid in poplar roots, and high N had the opposite effects. There were 552 and 247 significantly differentially abundant proteins (DAPs) in low and high vs normal N-supplied poplar roots, respectively. Notably, the abundances of a few poplar proteins, including nitrite reductase 1, glutamate synthase 1, and glutamate dehydrogenase 1, corresponded well to N-induced physiological changes in poplar roots. Functional characterization of N-responsive poplar ammonium transporter 2;1 and glutamate dehydrogenase 2 suggests both play pivotal roles in N uptake and assimilation in response to altering N levels. These results suggest that the growth, N uptake and assimilation, and phytohormonal levels are inhibited by N deficiency, but stimulated by high N, and the proteomic reconfigurations occur underlying these physiological alterations in poplars in acclimation to changing N availability.

Effects of surface and mixed application of sewage sludge on Neolamarckia cadamba root growth

The utilization of sewage sludge in forests is an important way of recycling. However, the effect of sewage sludge application on woody plant root growth has been rarely reported. The effects of surface application and mixed application of sewage sludge (mass ratio in 10%) on the dynamics in root morphology of a fast-growing tree species (Neolamarckia cadamba), soil pH, electric conductivity, and heavy metal content of roots in different soil layers were analyzed by a rhizobox experiment. The relationship between root length and soil pH value, electric conducti-vity, and root heavy metal content were further analyzed. Results showed that mixed application of sewage sludge inhibited root length, root surface area, and root volume. After 120 and 240 days of mixed application, total root length in the 0-20 cm soil layer was 76.9% and 67.4% of that of no sewage sludge application, respectively. Surface application of sewage sludge did not affect root length and root surface area but increased root volume. The mixed application of sewage sludge significantly increased soil pH, electric conductivity, and root heavy metal content. Root Cd contents in 0-20 cm and 20-40 cm soil layers with the mixed application of sewage sludge were 11.5 and 10.0 times as that of no sewage sludge application, respectively. Soil electric conductivity had a significant nega-tive correlation with root length in 0-20 cm soil layer among different treatments. Root Cd content had a significant negative correlation with root length in both the surface and the mixed applications of sewage sludge. These results indicated that mixed application of sewage sludge could inhibit N. cadamba root growth mainly by increasing soil electric conductivity and root Cd content, while the surface application of sewage sludge did not affect root growth.

Effects of grazing exclusion on soil infiltrability and preferential flow in savannah livestock grazing systems

AbstractAlthough the establishment of grazing exclosures is often considered an important strategy of reducing soil degradation, their effect on hydrological functions is still poorly understood, particularly in dry‐hot savanna systems with heavy livestock grazing. In addition, the different roles played by the herb roots and the niche differentiation of woody plant roots induced by the grazing and exclosure in soil hydrological functions are still unclear. This study aimed to evaluate the effect of exclosure management on hydrological functions and services and assess the role of different functional vegetation types in improving these functions and services. The experiments were conducted in the continuous grazing areas and exclosure areas in a savanna ecosystem in Yuanjiang, southwest China. The root biomass of herb and woody plants, soil physical properties, water infiltration, and preferential water flow were measured in each study site. The results showed a significant improvement in soil physical properties with more termite holes, lower soil bulk density, and higher total and non‐capillary soil porosity in exclosure areas compared with grazing ones. As a result, the initial and average water infiltration, and preferential flow significantly increased by 132.76%, 185.31%, and 30.29%, respectively, in exclosure areas compared with the grazing ones. The results also showed that the exclosure significantly improved the soil surface water content by increasing the root biomass of herb and woody plants in the shallow soil layers. Herb plants probably improved water infiltration and insulated evaporation, while woody plants improved lateral preferential water flow paths and accelerated the water exchange between vertical and horizontal soil layers, thereby improving the water availability for different plants. This study demonstrated that the exclosure‐induced restoration and niche differentiation of herb and woody plants, coupled with improved soil structure in exclosures, could promote hydrological function and services and improve water management in savanna systems. Therefore, the grazing exclosures could be expanded periodically and cautiously to prevent soil degradation in the present savanna systems.

Roots of invasive woody plants produce more diverse flavonoids than non-invasive taxa, a global analysis

Roots of invasive woody plants produce more diverse flavonoids than non-invasive taxa, a global analysis

X-ray computed tomography, electron microscopy, and energy-dispersive X-ray spectroscopy of severed Zelkova serrata roots (Japanese elm tree)

X-ray computed tomography (XCT), field emission scanning electron microscopy (FESEM), and energy-dispersive X-ray spectroscopy (EDS) were evaluated for imaging and element identification of woody plant roots. Lateral roots of Japanese zelkova (Zelkova serrata) were severed in spring and maintained in soil for six months. The lateral roots were observed using XCT without maceration and sectioning. The general wood characteristics were discernible to reveal the bark and xylem structures in contrast-inverted tomograms. Virtual sections showed a newly formed ring of woundwood encircling the severed lateral roots. FESEM exhibited secondary xylem structures in which tyloses, fungal hyphae, and aggregates were present. While silicon was dispersed in and around the fungal hyphae, calcium was localized as distinct aggregates using EDS. These results suggest that the combined use of XCT, FESEM, and EDS has merit into the morphological assessment of tree health care, providing virtual sections, high-resolution images, and element composition from an entire woodblock.

Transcriptome Profiling Reveals Differential Gene Expression of Secreted Proteases and Highly Specific Gene Repertoires Involved in Lactarius-Pinus Symbioses.

Ectomycorrhizal fungi establish a mutualistic symbiosis in roots of most woody plants. The molecular underpinning of ectomycorrhizal development was only explored in a few lineages. Here, we characterized the symbiotic transcriptomes of several milkcap species (Lactarius, Russulales) in association with different pine hosts. A time-course study of changes in gene expression during the development of L. deliciosus–Pinus taeda symbiosis identified 6 to 594 differentially expressed fungal genes at various developmental stages. Up- or down-regulated genes are involved in signaling pathways, nutrient transport, cell wall modifications, and plant defenses. A high number of genes coding for secreted proteases, especially sedolisins, were induced during root colonization. In contrast, only a few genes encoding mycorrhiza-induced small secreted proteins were identified. This feature was confirmed in several other Lactarius species in association with various pines. Further comparison among all these species revealed that each Lactarius species encodes a highly specific symbiotic gene repertoire, a feature possibly related to their host-specificity. This study provides insights on the genetic basis of symbiosis in an ectomycorrhizal order, the Russulales, which was not investigated so far.

Absorptive and transport roots differ in terms of their impacts on rhizosphere soil carbon storage and stability in alpine forests

The fine roots of woody plants can be classified as absorptive roots and transport roots based on their distinct morphological, physiological, and functional traits. The potential ecological consequences of roots with different functional classifications on soil biogeochemical processes have been widely recognized. However, the magnitude of rhizosphere soil C stocks and the associated C stabilization mechanisms driven by these two root functional modules remain unknown. We quantified the soil organic C (SOC) contents and the C fractions in the rhizospheres of absorptive and transport roots in mineral soil in a spruce (Picea asperata Mast.) plantation and further estimated the rhizosphere SOC stocks of the two root functional modules by establishing a numerical model based on the extent of the rhizosphere. We also determined the characteristics of the SOC chemistry and metal-organic complexation in the rhizosphere to distinguish how the two root functional modules differentially impact rhizosphere SOC stability. The SOC content of the rhizosphere of absorptive roots was 15.7% higher than that of the rhizosphere of transport roots. This result can be mainly attributed to the higher stability of SOC (i.e., chemical recalcitrance and metal-organic bond) in the rhizosphere of absorptive roots. The numerical model analysis showed that the rhizosphere SOC pool of absorptive roots (0.27–2.7 kg C/m2) was twice as large as that of transport roots (0.18–1.36 kg C/m2). The contribution of the rhizosphere SOC stock of absorptive roots (63.5%) to the total rhizosphere SOC accrual was much higher than that of the rhizosphere SOC stock of transport roots (36.5%) in the scenario with a 1-mm extent. The rhizosphere soil C stock of absorptive roots plays a predominant role in the total rhizosphere soil C stock in alpine coniferous forests. Our findings highlight the importance of integrating function-based fine root classifications with rhizosphere soil C storage into land surface models of C cycling, which would be instrumental for accurately predicting soil C dynamics in alpine coniferous forest ecosystems.

Anatomical patterns of condensed tannin in fine roots of tree species from a cool-temperate forest

Condensed tannin (CT) is an important compound in plant biological structural defence and for tolerance of herbivory and environmental stress. However, little is known of the role and location of CT within the fine roots of woody plants. To understand the role of CT in fine roots across diverse species of woody dicot, we evaluated the localization of CT that accumulated in root tissue, and examined its relationships with the stele and cortex tissue in cross-sections of roots in 20 tree species forming different microbial symbiotic groups (ectomycorrhiza and arbuscular mycorrhiza). In a cool-temperate forest in Japan, cross-sections of sampled roots in different branching order classes, namely, first order, second to third order, fourth order, and higher than fourth order (higher order), were measured in terms of the length-based ratios of stele diameter and cortex thickness to root diameter. All root samples were then stained with ρ-dimethylaminocinnamaldehyde solution and we determined the ratio of localized CT accumulation area to the root cross-section area (CT ratio). Stele ratio tended to increase with increasing root order, whereas cortex ratio either remained unchanged or decreased with increasing order in all species. The CT ratio was significantly positively correlated to the stele ratio and negatively correlated to the cortex ratio in second- to fourth-order roots across species during the shift from primary to secondary root growth. Ectomycorrhiza-associated species mostly had a higher stele ratio and lower cortex ratio than arbuscular mycorrhiza-associated species across root orders. Compared with arbuscular mycorrhiza species, there was greater accumulation of CT in response to changes in the root order of ectomycorrhiza species. Different development patterns of the stele, cortex and CT accumulation along the transition from root tip to secondary roots could be distinguished between different mycorrhizal associations. The CT in tissues in different mycorrhizal associations could help with root protection in specific branching orders during shifts in stele and cortex development before and during cork layer formation.

Biochar improves soil physical characteristics and strengthens root architecture in Muscadine grape (Vitis rotundifolia L.)

BackgroundBiochar is widely assumed as an effective soil amendment. It improves soil structure and fertility, thereby enhancing crop growth and development. There is still a knowledge gap in research on the beneficial impact of biochar on root growth and root architecture in perennial woody plants. Therefore, in our 14-week greenhouse study, pinewood-based biochar was applied as soil amendment for muscadine grape cultivation to investigate its effects on soil physical properties and crop root growth. Muscadine grape cv. Alachua was grown on Ultisols soil mixed with five rates of biochar on weight basis. Soil mixture properties and root attributes were determined.ResultsThe soil bulk density decreased 40% and the total porosity increased 50% by adding 20% biochar into pure sandy soil. The soil water-holding capacity (WHC) of 20% biochar amendment soil was 1.9 times as pure as sandy soil. In addition, the incorporation of biochar did not only ameliorate soil acidity at the beginning but also increased soil pH buffering capacity, providing suitable soil pH a few months after application. Moreover, biochar induced woody plant finer roots development and significantly promoted root length, number of root forks, and crossings, while decreasing root average diameter.ConclusionsPinewood biochar significantly improved soil physical properties by moderating soil thermal properties, buffering soil pH, improving soil WHC, decreasing soil bulk density, and increasing soil porosity. In addition, biochar also strengthened the root architecture by improving root length, number of root forks, and crossings. Furthermore, roots from the amended treatment had longer root length with less average diameter than unamended roots, indicating that biochar may stimulate muscadine fine root development. The incorporation of biochar in soil enhanced woody plant root growth and development improved soil structure in sandy soils. It could potentially be a good strategy to tackle water loss, particularly in sandy soils.

Global Distribution of the Reniform Nematode Genus Rotylenchulus with the Synonymy of Rotylenchulus macrosoma with Rotylenchulus borealis.

Reniform nematodes of the genus Rotylenchulus are semi-endoparasites of numerous herbaceous and woody plant roots that occur largely in regions with temperate, subtropical, and tropical climates. In this study, we compared 12 populations of Rotylenchulus borealis and 16 populations of Rotylenchulus macrosoma, including paratypes deposited in nematode collections, confirming that morphological characters between both nematode species do not support their separation. In addition, analysis of molecular markers using nuclear ribosomal DNA (28S, ITS1) and mitochondrial DNA (coxI) genes, as well as phylogenetic approaches, confirmed the synonymy of R. macrosoma with R. borealis. This study also demonstrated that R. borealis (= macrosoma) from Israel has two distinct rRNA gene types in the genome, specifically the two types of D2-D3 (A and B). We provide a global geographical distribution of the genus Rotylenchulus. The two major pathogenic species (Rotylenchulus reniformis and Rotylenchulus parvus) showed their close relationship with warmer areas with high annual mean temperature, maximum temperature of the warmest month, and minimum temperature of the coldest month. The present study confirms the extraordinary morphological and molecular diversity of R. borealis in Europe, Africa, and the Middle East and comprises a paradigmatic example of remarkable flexibility of ecological requirements within reniform nematodes.

Mid-Holocene soil water and vegetation in the Xi’an area of the southern Chinese Loess Plateau

This paper investigates mid-Holocene palaeo-vegetation and soil water in the Xi’an area of the southern Chinese Loess Plateau (CLP). A well-dated (8.5–6.0 ka BP and 5.0–3.1 ka BP) loess-palaeosol (unit S0) was logged, sampled and analyzed at four sites in the Xi'an area of the southern CLP, from which we report soil micromorphological (type and occurrence of root pores), particle size and geochemical data (CaCO3 and Sr concentration) to: (i) infer changes in soil water content, (ii) infer the limits of gravity water and the types of hydrologic cycle, and (iii) reconstruct the palaeovegetation. Numerous woody plant root holes were identified (2–4 mm diameter) within the illuvial horizon underlying palaeosol S0, the morphology of which is consistent with those produced by woody plants. The clay-rich argillic horizon of palaeosol S0 was found to contain high concentrations of kaolinite, which in concert with the geochemical indices, indicates that soil gravity water attained a depth of 2.2–2.8 m, whilst soil water content was ~20–25%. This implies that pedogenic processes at this site were more intense during the mid- compared to late Holocene loessic soils elsewhere on the CLP, and ultimately attests to relatively wet climatic conditions (e.g. up to 800 mm yr−1 rainfall), the hydrologic cycle type of precipitation-soil water-groundwater, and the vegetation of deciduous broad-leaved forest. We propose that combined analyses of root-channel morphology and mobile element geochemistry can be used to infer changes in palaeo-hydrology and ultimately, the strength of the Asian Summer Monsoon.